Transcript Planning and Preliminary Engineering Guide With the

PLANNING AND PRELIMINARY
ENGINEERING GUIDE FOR USING
THE HIGHWAY CAPACITY MANUAL
1
NCHRP 7-22 WORKSHOP
AGENDA
The Project
(9:00 AM)
Overview of the Guide
(9:30 AM)
Case Studies
Long Range Regional Plan Update
Freeway Master Plan
Urban Street BRT Project Planning
System Performance Monitoring
Wrap Up
(10:30 AM)
(11:30 AM)
(2:00 PM)
(2:45 PM)
(3:15 PM)
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1. NCHRP 7-22 PROJECT
NCHRP 7-22
To develop a guide to help planners take advantage of the
HCM to improve their results.
Status
4
• Stakeholder workshops held to identify planning needs and
how the HCM might help.
• Initial rough draft guide for stakeholder review (October)
• Revised draft guide for panel review in December.
• Final guide submitted for publication June 2015
THE PEOPLE
• The Research Team
• Kittelson & Associates - Rick Dowling, Paul Ryus
• North Carolina State University - Bastian Schroeder
• University of Idaho - Michael Kyte
• Stantec – Tom Creasey
• The Panel
Dirk Gross (Ohio) (Chair)
Tyrone Scorsone (CSI)
Robert Bryson (Milwaukee)
Brian Dunn (Oregon )
Jessie Jones (Arkansas)
Subrat Mahapatra (Maryland)
Erik Ruehr (VRPA)
Andrew Wolfe (SUNY)
Doug McLeod (Florida)
Jeremy Raw (FHWA)
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The Panel
2. OVERVIEW OF GUIDE
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09:30
CONTENTS
1. Part I - How To Use the Guide
A. Long and Short Range Areawide Planning
B. Project Traffic and Environmental Studies
C. Highway Performance Monitoring
2. Part 2 – Procedures
3. Part 3 – Case Studies
Long Range Regional Transportation Plan Analysis
Freeway Future Conditions Analysis
Analysis of BRT Project on Urban Street
Roadway System Monitoring
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A.
B.
C.
D.
Areawide Planning Analysis Task
Input to Travel Demand Models
Estimation of highway segment capacities, and free-flow
speeds
Traffic Assignment Module within the Travel Demand Model
Volume-Delay functions for the estimation of congested
speeds
Post Processing Travel Demand Model Outputs
Obtain more accurate speed estimates for air quality
analyses
Spotting auto v/c and LOS hot spots (quick screening)
Estimation of delay based on agency policy
Estimation of queuing
Interpretation of results
Travel time reliability analysis
Estimation of multimodal quality of service for autos, trucks,
transit, bicycles, and pedestrians
Corridor Analyses
Part 2
Reference
Part 3
Case
Studies
Section O4
Ex. I.1
Section O5
Ex. 1.2
Section O5
Ex. I.3
Section O5
Section O5
Section O5
Section O5
Section O5
Ex. I.4
Ex. I.5
Ex. I.5
Ex. I.6
Ex. 1.7
Ex. I.8
Ex. 1.9
-
Section O5
Section O6
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PART 1GATEWAY TO THE GUIDE
PART 1GATEWAY TO THE GUIDE
Input to Travel Demand Models (if used)
Estimation of highway capacities, and free-flow speeds
Traffic Assignment Module within the Demand Model (if used)
Volume-Delay functions for congested speeds
Input to Microsimulation Model (if used)
Estimation of free-flow speeds
Microsimulation Model Validation and Error Checking (if used)
Capacity estimates for error checking simulated bottlenecks
Project Impact & Alternatives Analyses
Estimating segment speeds for air quality and noise analyses
Estimating auto intersection utilization (v/c)
Estimation of delay
Estimation of queuing
Interpretation of results
Travel time reliability analysis
Estimation of multimodal quality of service for autos, trucks,
transit, bicycles, and pedestrians
Corridor Analyses
Part 2
Reference
Part 3
Case Studies
Sections O4
Ex. I.1
Section O5
Ex. 1.2
Section O4
Ex. I.1
Section O4
Ex. I.1
Sections E-H
Sections H-K
Sections H-K
Sections H-K
Sections E-K
Sections E-H
Case Studies 2-3
Case Studies 2-3
Case Studies 2-3
Case Studies 2-3
Case Studies 2-3
Case Studies 2-3
Sections E-H Case Studies 2-3
Section O6
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Project Impact & Alternatives Analysis Task
Performance Monitoring Task
Part 2
Reference
Part 3
Case Studies
Estimation of monitoring site capacities, and free-flow speeds
Sections O4
Ex. IV.1
Section O5
Ex. IV.2
Section O5
Ex. IV.3
Section O5
Section O5
Section O5
Section O5
Section O5
Section O5
Ex. IV.4
Ex. IV.5
Ex. IV.5
Ex. IV.5
Ex. IV.5
Ex. IV.5
Section O5
Ex. IV.5
For Volume Only Monitoring Sites
Estimation of speeds
For Travel Time Only Monitoring Segments
Estimation of volumes
Performance Analyses
Quality Assurance/Quality Control
Auto and Truck VMT
Auto and Truck VMT by LOS
Estimation of delay
Estimation of queuing
Travel time reliability analysis
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Estimation of multimodal quality of service for trucks,
transit, bicycles, and pedestrians
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PART 1GATEWAY TO THE GUIDE
PART 2 - PROCEDURES
A.
Default Values
B.
Generalized Service Volume Tables
C.
Working with Traffic Demand Data
D.
Intersection Traffic Control
E.
Guidance for Freeways
F.
Guidance for Multilane Highways
G.
Guidance for Two-Lane Highways
H.
Guidance for Urban Streets
I.
Guidance for Signalized Intersections
J.
Guidance for Stop-Controlled Intersections
Input Data
Facilities
Intersections
Guidance for Roundabouts
L.
Guidance for Interchange Ramp Terminals
M.
Guidance for Off-Street Pathways
N.
Guidance for Corridors
O.
Guidance for Areas and Systems
Other
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K.
PART 2 – SECTION E:
FREEWAY PROCEDURES
• E1. Overview
• E2. Computational Tools
• E3. Data Needs
• E4. Estimating Inputs
• Free flow Speed
• Capacity
• E5. Performance Measures
Speed
Level of Service
Queues
Reliability
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E. GUIDANCE FOR FREEWAYS
A freeway is a separated highway with full control of
access and two or more lanes in each direction dedicated
to the exclusive use of motorized vehicles. Freeways are
composed of various uniform segments that may be
analyzed to determine capacity and level of service (LOS).
Three types of segments are found on freeways:
•
•
•
Freeway merge and diverge segments: Segments
in which two or more traffic streams combine to
form a single traffic stream (merge) or a single traffic stream divides to form two or more
separate traffic streams (diverge).
Freeway weaving segments: Segments in which two or more traffic streams traveling in the
same general direction cross paths along a significant length of freeway without the aid of traffic
control devices (except for guide signs). Weaving segments are formed when a diverge segment
closely follows a merge segment or when a one‐lane off‐ramp closely follows a one‐lane on‐
ramp and the two are connected by a continuous auxiliary lane.
Basic freeway segments: All segments that are not merge, diverge, or weaving segments.
The planning method for freeways focuses on facility level analysis and section level analysis. A section is
defined as extending from gore point to gore point, avoiding the need to subdivide the section into 1500
foot long merge and diverge areas. A section may combine several HCM segments. For example, a
section extending between and on-ramp and an
off-ramp may be composed of 3 HCM segments: a
Exhibit E-1: Freeway Analysis Approaches
merge segment, a basic or weave segment, and a
diverge segment. If the individual segment level
analysis is desired then the procedures in the
HCM are recommended with defaults for certain
inputs. For facility and section level analysis, a
simplified version of the HCM operations analysis
method is presented.
E2. COMPUTATIONAL TOOLS
Two general approaches are available for planning
analyses of Freeways. These are:
Generalized service volume table. Using a
minimum of input data, AADT and number of
lanes, the service volume table provides the
expected LOS on a freeway facility for a given
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FIRST PAGE - INTRO
E1. OVERVIEW
FREEWAY DATA NEEDS
Required to Estimate
FFS
Cap
Spd
LOS
Que
Rel
Segment design
geometry
•
•
•
•
•
•
Percent heavy vehicles
(%)
•
•
•
•
•
Number of directional
lanes
•
•
•
•
•
Peak hour factor
(decimal)
•
•
•
•
•
Driver pop factor
(decimal)
•
•
•
•
•
Segment length (mi)
•
•
•
•
Directional demand
(veh/h)
•
•
•
•
Comments/Defaults
10% (rural), 5% (urban)
Must be provided
0.88 (rural), 0.95 (urban)
1.00
Must be provided
Must be provided
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Input Data (units)
The most accurate method for estimating segment free-flow speeds is to measure it in the field during
low flow (under 800 veh/hr/ln)1. In urban environments, traffic sensors may be available to allow the
estimation of free-flow speeds, however for planning applications this is not usually practical. The HCM
provides an equation for estimating free-flow speeds based on facility geometry.2
𝑭𝑭𝑺 = 𝟕𝟓. 𝟒 − 𝒇𝑳𝑾 − 𝒇𝑳𝑪 − 𝟑. 𝟐𝟐𝑻𝑹𝑫𝟎.𝟖𝟒
Equation E-1
Where:
-
-
-
FFS = free-flow speed (mi/h)
fLW = adjustment for lane width (mi/h)
o (0.0 for 12 foot or greater lanes, 1.9 for 11 foot lanes, 6.6 for 10 foot lanes) (see exhibit
11-8, HCM 2010 for details)
fLC = adjustment for right side lateral clearance (mi/h)
o ranges from zero for 6 foot lateral clearance to 3.0 for one foot lateral clearance on a 2
directional lane freeway (see Exhibit 11-9, HCM 2010 for details).
TRD = total ramp density (ramps/mi)
o Number of on and off-ramps in one direction for 3 miles upstream and 3 miles
downstream, divided by 6 miles.
An alternate approach is to assume the free-flow speed (the average speed of traffic under low flow
conditions) is equal to the posted speed limit plus an adjustment reflecting local driving behavior.
Florida adds 5 mi/h to the posted speed limit.
Estimating Section Capacities
Free flow speed and percent heavy vehicles are used to calculate section capacity using the following
equation:
𝒄𝒊 =
𝟐, 𝟐𝟎𝟎 + 𝟏𝟎 ∗ 𝐦𝐢𝐧 𝟕𝟎, 𝑺𝑭𝑭𝑺 − 𝟓𝟎
𝟏 + %𝑯𝑽/𝟏𝟎𝟎
∗ 𝑪𝑨𝑭
Equation E-2
Where:

Ci = capacity of section “I” (vph/ln)
1
Adapted from Exhibit 11-3, HCM 2010, accounting for likely peak hour factor and heavy vehicle effects.
2
Souce: equation 11-1, HCM 2010.
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TYPICAL PROCEDURES
Estimating Free-Flow Speed
PART 2 – SECTION H:
URBAN STREET PROCEDURES
• H1. Overview
• H2. Computational Tools
• H3. Data Needs
• H4. Segment Performance
• H5. Intersection Perform.
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• H6. Facility Performance
H. GUIDANCE FOR URBAN STREETS
H1. OVERVIEW
There is one caveat to this inclusionary approach for interrupted Exhibit H-1: Urban Street Analysis
flow facilities. The HCM methodology focuses on evaluating the
speed of through traffic for interrupted flow facilities. However,
this is not an appropriate performance measure for evaluating
local street performance. Therefore, the methods described in
this section and the HCM methodology for uninterrupted flow
facilities are not appropriate for the evaluation of local streets.
The planning methods for urban streets focus on facility level
analysis, segment level analysis, and intersection level analysis.
Facility level performance is estimate by summing the segment
(between intersection) and intersection level performance
results.
H2. COMPUTATIONAL APPROACH
The planning analyses of urban streets proceed in 4 phases. In
phase 1, a screening analysis is performed using service volume
tables to determine if more detailed planning analysis may be
required to identify traffic operations problems on the street. If
so, then the next 3 phases of planning analysis are performed:
Segment Analysis, Intersection Analysis, and finally, Facility
Analysis.
H3. DATA NEEDS
Error! Reference source not found. lists the data needed to
evaluate the full range of performance measures for planninglevel urban street analysis. Individual performance measures
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FIRST PAGE
Any street or roadway with traffic signals, roundabouts,
all-way stops, or two-way stops (interrupting the
through traffic movements) that are spaced no farther
than 2 mi apart can be evaluated using the HCM
methodology for “urban streets.” The street usually is
located in a suburban or urban area with frequent
driveway access to fronting properties, but that is not a
requirement for use of the HCM urban streets analysis
method. All streets and roadways meeting the 2-mile criteria are grouped under the broad category of
“interrupted flow facilities” and may be evaluated using the procedures described here and in Volume 3
of the 2010 HCM.
URBAN STREET DATA NEEDS
Spd
LOS
MMLOS
•
•
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•
•
•
Analysis Period Length (h)
•
•
Segment length (mi)
•
•
Directional demand (veh/h)
•
•
FFS
Posted Speed Limit (mi/h)
Intersection Data
Cross-section, bus stops
Cap
•
•
Que
Rel
Comments/
Defaults
•
required
•
•
required
•
•
0.25 h
•
•
•
required
•
•
•
required
required
•
Seasonal demand data
•
Defaults in appendix
Incident data
•
Defaults in appendix
Local weather history
•
Source in appendix
Workzone probability
•
Defaults in appendix
18
Input Data (units)
Speed - Segment
The average speed over the segment, inclusive of intersection and midblock bottleneck delays is
estimated using the following procedure.
The midblock freH-flow speed can be measured in the field or estimated. It is the average spot speed of
traffic measured at the mid-point of the segment (see Chapter 30, HCM 2010 for details of
measurement method). It can also be estimated using the table and equations provided in Chapter 17,
HCM 2010, which are sensitive to signal spacing, median type, curbs and driveway access points. The
analyst may also estimate the midblock freH-flow speed by applying an adjustment based on local
knowledge of speed limit compliance to the posted speed limit for the segment as follows:
𝐅𝐅𝐒 = 𝑷𝑺𝑳 + 𝑨𝑫𝑱
Equation H-1
Where
FFS = the midblock freH-flow speed (mi/h)
PSL = the posted speed limit (mi/h)
ADJ = Adjustment based on local knowledge (mi/h) – may be positive or negative.
Estimate Intersection delay
The intersection control delay is estimated using the appropriate intersection planning method (see
Section Error! Reference source not found.) for references to the specific sections in this guide.
Estimate Midblock Delay (if any)
Midblock delays are not often present on urban streets; however, If there is a lane drop between
intersections (such as might occur at a narrow bridge, or when lanes are added right before an
intersection and dropped just after the intersection) then the lane drop creates a midblock bottleneck
which may add significant delay when demand is greater than its capacity. The average delay at the
midblock bottleneck can be approximated using the equation below. A more precise estimate, taking
into account the effects of queue storage, can be made using the method describe in Error! Reference
source not found..
Equation H-2
𝑑=
𝑇
𝑣
𝑚𝑎𝑥 0,
−1
2
𝑐
Where
d = average delay due to bottleneck (s/veh).
T = analysis period duration (s) (default = 900 secs)
v = volume (veh/h)
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TYPICAL PROCEDURE
Measure or Estimate Midblock Free Flow Speed
PART 2 SECTION I –
SIGNALIZED INTERSECTIONS
• I1. Overview
• I2. Computational Tools
• I3. Data Needs & Limits
• I4. Performance Estimation
Screening – Critical Lane Vol.
v/c ratio
Delay
LOS
Queue
Reliability (sensitivity analysis)
Bike/Ped LOS – see Section M
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•
SIGNALIZED INTERSECTION
DATA NEEDS
Required to Estimate
Cap
Del
LOS
MMLOS
Que
Rel
Comments/Defaults
Number of turn lanes
•
•
•
•
•
n/a
required
Other geometry
•
•
•
•
•
Defaults provided
Signal Timing (cycle, g/c)
•
•
•
•
•
Defaults provided
Peak Hour Factor (decimal)
•
•
•
•
0.88 (rural), 0.95 (sub.)
Percent heavy vehicles (%)
•
•
•
•
•
10 (rural), 5 (suburban)
•
•
•
•
required
•
•
•
•
•
•
Turning demands (veh/h)
Other demands (ped, park)
Analysis Period Length (h)
•
0.25 h
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Input Data (units)
PART 2 SECTION O –
AREAWIDE ANALYSES
• O1. Overview
• O2. Computational Tools
• O3. Data Needs
• O4. Estimate Demand Model Inputs
• Free-Flow Speed
• Capacity
• O5. Performance Measures
22
• Auto – V/C, Speed, VHT, Delay, LOS, Density, Queue,
Reliability.
DATA NEEDS –
AREAWIDE ANALYSIS
Required to Estimate
Facility Type
Segment design
geometry
Terrain type
Percent heavy vehicles
(%)
Peak hour factor
(decimal)
Driver pop factor
(decimal)
Number of directional
lanes
Segment length (mi)
Directional demand
(veh/h)
FFS
Cap
Spd
Que
Rel
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
Comments/Defaults
Defaults by area and facility type
Defaults by area and facility type
Must be provided
10% (rural), 5% (urban)
0.88 (rural), 0.95 (urban)
1.00
Must be provided
Must be provided
Output of Travel Model
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Input Data (units)
Facility
Type
Area Type
Downtown
Urban
Freeway
Suburban
Rural
Downtown
Urban
Arterial
Suburban
Rural Multi-Lane
Rural 2-Lane
Downtown
Urban
Collector Suburban
Rural Multi-Lane
Rural 2-Lane
Free-Flow
Speed (mph)
55
60
65
70
25
35
45
55
55
25
30
35
45
45
G/C
HCM PC
Capacity
(veh/ln)
90% PC
Capacity
(veh/ln)
80% PC
Capacity
(veh/ln)
n/a
n/a
n/a
n/a
0.45
0.45
0.41
n/a
n/a
0.41
0.41
0.37
n/a
n/a
2250
2300
2350
2400
860
860
780
2100
1600
780
780
700
1900
1600
2000
2100
2100
2200
800
800
700
1900
1400
700
700
600
1700
1400
1800
1800
1900
1900
700
700
600
1700
1300
600
600
600
1500
1300
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“NO-FAULT”
CAPACITY LOOK UP TABLE
MULTIMODAL LOS
DASHBOARD – FOR SYSTEMS
Facility Type
Freeways
Urban
Non-Freeway
Mode
Auto
Truck
Auto
Truck
Transit
Bicycle
Pedestrian
LOS A-C LOS D LOS E LOS F
7%
24%
38%
31%
4%
20%
38%
38%
16%
34%
34%
16%
5%
22%
38%
34%
10%
29%
38%
24%
12%
31%
37%
21%
31%
38%
24%
7%
Total
100%
100%
100%
100%
100%
100%
100%
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Area Type
COMMENTS SO FAR?
• Outline and Contents of Guide (Part 1, 2, 3)
• What do you like so far?
• What do you dislike?
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• What is missing?
10:30
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3. CASE STUDIES
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CASE STUDY #1 – REGIONAL PLANNING
CASE 1 - LRTP
Fresno COG 2040 Regional Transportation Plan
- 6,000 square miles
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- 1 million population
OBJECTIVES
• Conduct transportation performance and investment
alternatives analysis required to update 2040 LRTP
• Auto, truck, bus, bicycle, and pedestrian analyses to be
performed.
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• Travel Demand Forecasting Model to be Used
EXAMPLE PROBLEMS
•
Example Problems that Develop Demand Model Inputs
•
• Example I.1 – Estimation of Free-Flow Speeds and Capacities
• Example I.2 – HCM Based Volume-Delay Functions
Example Problems Post Processing Demand Model Outputs
Example I.3 – Estimating Speeds for Air Quality & Noise Analysis
Example I.4 – Screening for Auto V/C and LOS Hot Spots
Example I.5 – Predicting Queues & Delay
Example I.6 – Interpretation of Results
Example I.7 – Prediction of Reliability
Example I.8 – Transit, bicycle, and pedestrian LOS screening
Example I.9 – Truck LOS screening
31
•
•
•
•
•
•
•
EXAMPLE I.1 – ESTIMATING FREEFLOW SPEEDS & CAPACITIES
• Objective
• To develop lookup table of free-flow speeds and capacities
for coding the highway network
• Approach
32
• Step 1: Identify facility categorization scheme
• Step 2: Determine free-flow speeds
• Step 3: Determine capacities
PICKING FACILITY TYPES
Facility Type
Freeway
Principal Highway
Minor Highway
Arterial
Area Type
Free-Flow Speed
(mi/h)
Capacity
(veh/ln)
Downtown
Urban
Suburban
Rural
Rural Multi-Lane
Rural Two-Lane
Rural Multi-Lane
Rural Two-Lane
Downtown
Urban
Suburban
Suburban
33
Collector
Downtown
Urban
FOR FREE-FLOW SPEEDS
• Consult Appropriate HCM Chapter for Procedure, or
34
• Use Posted Speed Limit + 5 mph
FOR FREE-FLOW SPEEDS
• Consult Appropriate HCM Chapter for Procedure, or
35
• Use Posted Speed Limit + 5 mph
Facility
Type
Freeway
Arterial
Collector
Area Type
Downtown
Urban
Suburban
Rural
Downtown
Urban
Suburban
Rural Multi-Lane
Rural 2-Lane
Downtown
Urban
Suburban
Rural Multi-Lane
Rural 2-Lane
Free-Flow
Speed
(mph)
55
60
65
70
25
35
45
55
55
25
30
35
45
45
G/C
HCM PC
Capacity
(veh/ln)
90% PC
Capacity
(veh/ln)
80% PC
Capacity
(veh/ln)
n/a
n/a
n/a
n/a
0.45
0.45
0.41
n/a
n/a
0.41
0.41
0.37
n/a
n/a
2250
2300
2350
2400
860
860
780
2100
1600
780
780
700
1900
1600
2000
2100
2100
2200
800
800
700
1900
1400
700
700
600
1700
1400
1800
1800
1900
1900
700
700
600
1700
1300
600
600
600
1500
1300
Arterial/Collector assume 1900 ideal sat flow rate
36
USE “NO-FAULT” CAPACITY
TABLE FROM PART 2 - SECTION O
Facility
Type
Freeway
Arterial
Collector
Area Type
Downtown
Urban
Suburban
Rural
Downtown
Urban
Suburban
Rural Multi-Lane
Rural 2-Lane
Downtown
Urban
Suburban
Rural Multi-Lane
Rural 2-Lane
Free-Flow
Speed
(mph)
55
60
65
70
25
35
45
55
55
25
30
35
45
45
G/C
HCM PC
Capacity
(veh/ln)
90% PC
Capacity
(veh/ln)
80% PC
Capacity
(veh/ln)
n/a
n/a
n/a
n/a
0.45
0.45
0.41
n/a
n/a
0.41
0.41
0.37
n/a
n/a
2250
2300
2350
2400
860
860
780
2100
1600
780
780
700
1900
1600
2000
2100
2100
2200
800
800
700
1900
1400
700
700
600
1700
1400
1800
1800
1900
1900
700
700
600
1700
1300
600
600
600
1500
1300
Arterial/Collector assume 1900 ideal sat flow rate
37
PICK 80% HCM PC CAPACITY
Facility Type
Freeway
Principal Highway
Minor Highway
Arterial
Collector
Area Type
Downtown
Urban
Suburban
Rural
Rural Multi-Lane
Rural Two-Lane
Rural Multi-Lane
Rural Two-Lane
Downtown
Urban
Suburban
Downtown
Urban
Suburban
Free-Flow Speed
(mi/h)
Capacity
(veh/ln)
55
60
65
70
55
55
45
45
25
35
45
25
30
35
1800
1800
1900
1900
1700
1300
1500
1300
700
700
600
600
600
600
38
EXAMPLE RESULT
COMMENTS?
39
Example I.1 – Creation of free-flow speed and capacity lookup tables
EXAMPLE #I.2 – HCM BASED
VOLUME-DELAY FUNCTIONS
• Objective
• To select an HCM based volume-delay function for
demand model
• Approach
• Step 1: Select volume-delay function type
•
BPR and Akcelik
• Step 2: Set parameters
•
•
•
Match Speed at Capacity
Compute Akcelik parameter
Compute BPR parameter
40
• Step 3: Select preferred volume-delay function
AKCELIK
T  T 0  0.25 x  1 

x  1
2
 16 J  L  x 

2
41
Where:
T0 = Free-flow travel time
X = volume/capacity ratio
J = calibration parameter
L = length of the link
BPR
T  T 0 * [1  A * ( x) ]
B
42
Where:
T0 = Free-flow travel time
X = volume/capacity ratio
A = speed at capacity calibration parameter
B = rate of travel time increase calibration parameter
SMOOTH VS ROUGH PIPE
BPR
Akcelik
Everybody
waits their
turn here.
T
Free-Flowing
here
43
Everybody
goes slow
entire length
SPLITTING SMOOTH &
ROUGH PIPES
0.5 T
or T
Problem for DTA,
No Problem for SUE Models
Akcelik
T
T or
2T
No Problem for DTA,
Problem for SUE Models
44
BPR
45
COMPARING SPEEDS
COMPARING SPEEDS
46
Speed at
Capacity
CALIBRATING TO SPEED AT
CAPACITY
BPR
A
Sf
Sc
1
47
Akcelik
1
1 
J  

 S c S f 
2
CALIBRATED CURVES
Area Type
Downtown
Free-Flow
Speed
(mi/h)
55
1800
HCM Speed at
Capacity
(mi/h)
50.0
Capacity
(veh/ln)
BPR “a”
Akcelik “J”
Parameter
Parameter
0.10
3.31E-06
Urban
60
1800
51.1
0.17
8.43E-06
Suburban
65
1900
52.2
0.25
1.42E-05
Rural
70
1900
53.3
0.31
2.00E-05
Principal
Highway
Rural Multi-Lane
55
1700
47.1
0.17
9.30E-06
Rural Two-Lane
55
1300
47.0
0.17
9.58E-06
Minor
Highway
Rural Multi-Lane
45
1500
39.6
0.14
9.18E-06
Rural Two-Lane
45
1300
37.0
0.22
2.31E-05
Downtown
25
700
23.2
0.08
9.63E-06
Urban
35
700
31.6
0.11
9.45E-06
Suburban
45
600
39.6
0.14
9.18E-06
Downtown
25
600
23.2
0.08
9.63E-06
Urban
30
600
27.4
0.09
1.00E-05
Suburban
35
600
31.6
0.11
9.45E-06
Freeway
Arterial
Collector
48
Facility
Type
ALL GET SAME SPEED AT
CAPACITY
49
Speed at
Capacity
50
COMPARING TRAVEL TIMES
COMPARING TO HCM
51
Akcelik vs. HCM
COMMENTS?
52
Example I.2 – Selection of Volume-Delay Functions
EXAMPLE I.3 – SPEEDS FOR
AIR QUALITY ANALYSIS
• Objective:
• to develop a speed-flow equation that accurately reflects
queueing delays for post-processing travel demand model
outputs for air quality analysis purposes.
• Procedure:
Step 1: Identify free-flow speeds and capacities
Step 2: Select appropriate Akcelik parameters for links
Step 3: Compute speed for link
Step 4: Interpretation of Results
53
•
•
•
•
Link ID
Type
v/c
Original Model Speed (mi/h)
A001
Freeway-Urban
1.14
48
A002
Arterial-Urban
0.83
33
A003
Collector-Urban
0.98
26
A004
Freeway-Rural
0.73
67
A005
Highway-Rural
0.44
55
A006
Collector-Rural
0.19
45
54
POST PROCESSING MODEL
SPEEDS
Link ID
Type
v/c
Original Model Speed (mi/h)
A001
Freeway-Urban
1.14
48
A002
Arterial-Urban
0.83
33
A003
Collector-Urban
0.98
26
A004
Freeway-Rural
0.73
67
A005
Highway-Rural
0.44
55
A006
Collector-Rural
0.19
45
55
POST PROCESSING MODEL
SPEEDS
Free
Demand
Speed
(veh/h)
(mi/h)
80% PC
Capacity
(veh/h/ln)
Akcelik
“J”
Segment
Capacity
(veh/h)
v/c
Speed
(mi/h)
60
1800
8.40E-06
7,200
1.14
10.0
1,740
35
700
9.34E-06
2,100
0.83
18.7
CollectorUrban
1,170
30
600
9.34E-06
1,200
0.98
26.2
2.50
FreewayRural
2,790
70
1900
1.99E-05
3,800
0.73
68.7
A005
4.50
HighwayRural
1,490
55
1700
9.34E-06
3,400
0.44
51.5
A006
7.30
CollectorRural
250
45
1300
2.31E-05
1,300
0.19
44.8
Link
ID
Length
(mi)
Type
A001
0.85
FreewayUrban
8,220
A002
0.21
ArterialUrban
A003
1.34
A004
56
POST PROCESSING (2)
RESULTS – NEW SPEEDS
Link ID
Type
v/c
Original Model
Speed (mi/h)
Revised Speed
(mi/h)
A001
Freeway-Urban
1.14
48
10
A002
Arterial-Urban
0.83
33
19
A003
Collector-Urban
0.98
26
26
A004
Freeway-Rural
0.73
67
69
A005
Highway-Rural
0.44
55
52
A006
Collector-Rural
0.19
45
45
57
Short vs long segments
INTERPRETATION
Short vs long segments
Type
v/c
Original Model
Speed (mi/h)
Revised Speed
(mi/h)
A001
Freeway-Urban
1.14
48
10
A002
Arterial-Urban
0.83
33
19
A003
Collector-Urban
0.98
26
26
A004
Freeway-Rural
0.73
67
69
A005
Highway-Rural
0.44
55
52
A006
Collector-Rural
0.19
45
45
58
Long (> 1mile)
Link ID
COMMENTS?
59
Example I.3 – Refining speed estimates for air quality
analysis.
EXAMPLE I.4 – SCREENING
FOR AUTO HOT SPOTS
• Objective:
• To identify auto volume/capacity ratio and level of service
problem spots within the highway system.
• Procedure:
60
• Step 1: Compute v/c for links
• Step 2: Estimate LOS for links
Free-Flow
LOS A-C
Speed (mi/h)
Facility Type
Area Type
LOS D
LOS E
Freeway
Rural
65
0.70
0.85
1.00
Freeway
Urban
65
0.65
0.85
1.00
Multilane Highway
Rural
60
0.65
0.85
1.00
Two Lane Highway
Rural
N.D.
N.D.
N.D.
N.D.
Arterial
Urban
45
0.50
0.90
1.00
Arterial
Urban
25-35
0.30
0.80
1.00
61
AUTO V/C LOS TABLE
Free-Flow
LOS A-C
Speed (mi/h)
Facility Type
Area Type
LOS D
LOS E
Freeway
Rural
65
0.70
0.85
1.00
Freeway
Urban
65
0.65
0.85
1.00
Multilane Highway
Rural
60
0.65
0.85
1.00
Two Lane Highway
Rural
Arterial
Urban
45
0.50
0.90
1.00
Arterial
Urban
25-35
0.30
0.80
1.00
62
V/C LOS LOOKUP TABLE
Type
Demand
(veh/h)
Free
Speed
(mi/h)
Segment
Capacity
(veh/h)
v/c
LOS
0.85
Freeway-Urban
8,220
60
7,200
1.14
F
A002
0.21
Arterial-Urban
1,740
35
2,100
0.83
E
A003
1.34
Collector-Urban
1,170
30
1,200
0.98
E
A004
2.50
Freeway-Rural
2,790
70
3,800
0.73
D
A005
4.50
Highway-Rural
1,490
55
3,400
0.44
A-C
A006
7.30
Collector-Rural
250
45
1,300
0.19
A-C
Link
ID
Length
(mi)
A001
63
EXAMPLE V/C & LOS COMP.
COMMENTS?
64
Example I.4 – V/C and LOS Screening
EXAMPLE I.5 – DENSITY,
QUEUES, DELAY
• Objective:
• To compute and report the density of traffic, hours spent in
queues, and hours delay within the highway system.
• Procedure:
Step 1: Compute Density
Step 2: Compute Vehicle-Hours in Queue
Step 3: Compute Vehicle-Hours of Delay
Step 4: Interpretation of Results
65
•
•
•
•
DENSITY
𝐷 = 1.2 ∗
𝑣
𝑁∗𝑆
Where:
D = density (pc/mi/ln)
v = demand (veh/h)
N = number of lanes
S = speed (mi/h)
PCE = passenger car equivalent
𝑉𝐻𝐷 =
𝑣∗𝐿 𝑣∗𝐿
−
𝑆
𝑆𝑃
Where:
VHD = Vehicle-hours delay
V = demand (veh/h)
L = length of link (mi)
S = speed (mi/h)
SP = agency’s policy minimum acceptable
speed for facility (mi/h)
66
VEH-HRS DELAY
VEH-HRS IN QUEUE
• Sum of vehicle-hours spent on links with
• v/c > 1.00 or
• speed below the speed at capacity.
• Sum of vehicle-hours delay at intersections
• Average delay at intersection (converted into hours)
multiplied by total vehicles entering intersection.
Exclude free right turn volumes
67
•
COMMENTS?
68
Example I.5 – Density, Delay, Queue Calculations
EXAMPLE I.6 – REPORTING
SYSTEM RESULTS
Link
ID
A001
A002
A003
A004
A005
A006
Type
FreewayUrban
ArterialUrban
CollectorUrban
FreewayRural
HighwayRural
CollectorRural
Total
Outputs
L
v
c
FFS CSpd
S
v/c
0.85
8,220
7,200
60
0.21
1,740
2,100
1.34
1,170
2.50
VMT
VHT
VHD
VHQ
51.1
10.0
1.14
6,987
700
563
563
35
31.6
18.7
0.83
365
20
8
0
1,200
30
27.5
26.2
0.98
1,568
60
3
0
2,790
3,800
70
53.3
68.7
0.73
6,975
102
0
0
4.50
1,490
3,400
55
47.1
51.5
0.44
6,705
130
0
0
7.30
250
1,300
45
37.0
44.8
0.19
1,825
24,425
41
1,051
0
574
0
563
69
Inputs
REPORTING SYSTEM LOS
Facility Type
Freeways
Urban
Non-Freeway
Mode
Auto
Truck
Auto
Truck
Transit
Bicycle
Pedestrian
LOS A-C
LOS D
LOS E
LOS F
7%
4%
16%
5%
10%
12%
31%
24%
20%
34%
22%
29%
31%
38%
38%
38%
34%
38%
38%
37%
24%
31%
38%
16%
34%
24%
21%
7%
Total
100%
100%
100%
100%
100%
100%
100%
70
Area Type
COMMENTS?
71
Example I.6 – Reporting System Results
EXAMPLE I.7 – PREDICTION
OF RELIABILITY
• Objective:
• To identify auto reliability problem spots and causes within
the highway system.
• Procedure:
Step 1: Compute average annual TTI for links
Step 2: Compute average annual TTI for system
Step 3: Compute 95th percentile annual TTI for system
Step 4: Interpretation of results
72
•
•
•
•
Travel Time (min)
73
Number of Trips
TRAVEL TIME RELIABILITY
95th Percentile
Trips
< 45 mph
Travel Time (min)
74
Mean
Free Flow
Number of Trips
CHARACTERIZING
RELIABILITY
𝑇𝑇𝐼95 =
𝑇𝑇95
𝑇𝑇𝐹𝑟𝑒𝑒−𝐹𝑙𝑜𝑤
Travel Time (min)
75
95th Percentile
Mean
Free Flow
Number of Trips
THE TTI STATISTIC
Free Flow
𝑃𝑇45 =
𝑇𝑟𝑖𝑝𝑠<45
𝑇𝑜𝑡𝑎𝑙 𝑇𝑟𝑖𝑝𝑠
Trips
< 45 mph
Length/45
Travel Time (min)
76
Number of Trips
THE PERCENT < 45 MPH
RELIABILITY PREDICTION
• Average Annual TTI
• 𝑻𝑻𝑰𝒎 = 𝟏 + 𝑭𝑭𝑺 ∗ 𝑹𝑫𝑹 + 𝑰𝑫𝑹
• Recurring Delay Rate
• 𝑹𝑫𝑹 =
𝟏
𝑺
−
𝟏
𝑭𝑭𝑺
• Incident Delay Rate
Where:
TTIm = average annual mean travel
time index (unitless)
FFS = free-flow speed (mi/h)
RDR = Recurring delay rate (h/mi)
IDR = Incident Delay Rate (h/mi
S = peak hour speed (mi/h)
N = number of lanes one direction
X = peak hour v/c
77
• 𝑰𝑫𝑹 = 𝟎. 𝟎𝟐𝟎 − 𝑵 − 𝟐 ∗ 𝟎. 𝟎𝟎𝟑 ∗ 𝑿𝟏𝟐
RELIABILITY STATS
𝑻𝑻𝑰𝟗𝟓 = 𝟏 + 𝟑. 𝟔𝟕 ∗ 𝐥𝐧 𝑻𝑻𝑰𝒎
𝑷𝑻𝟒𝟓 = 𝟏 − 𝐞𝐱𝐩 −𝟏. 𝟓𝟏𝟏𝟓 ∗ 𝑻𝑻𝑰𝒎 − 𝟏
• where
• TTI95 = the 95th percentile TTI;
• PT45 = the percent of trips that at speeds less than 45 mph
78
TTI95 is the ratio of the 95th percentile highest travel time
to the free-flow travel time
RELIABILITY STATS (2)
Link ID
Type
A001
Fwy-Urban
116
8.34E-02
6.86E-02
10.13
1,179
1,179
A002
Art-Urban
10
2.49E-02
1.78E-03
1.93
20
20
A003
Coll-Urban
52
4.79E-03
1.48E-02
1.59
83
83
A004
Fwy-Rural
100
2.73E-04
4.91E-04
1.05
105
0
A005
Hiwy-Rural
122
1.23E-03
1.00E-06
1.07
130
0
A006
Coll-Rural
41
8.02E-05
5.12E-11
1.00
41
41
3.53
1,558
RDR
IDR
441
57%
43%
TTIm
VHTm
TTI95
5.63
VHT<45
1,323
85%
79
Total or Ave.
VHT(FFS)
RELIABILITY GOOD?
• Areawide Results
• 95%TTI = 5.63
• % Trips < 45 mph = 85%
• Good, Bad, or Ugly?
Level of
Service
A
B
C
D
E
F
5% Speed
95% TTI
>60 mi/h
55-60
45-55
35-45
25-35
<=25
<1.08
1.08-1.18
1.18-1.44
1.44-1.86
1.86-2.60
>= 2.60
80
Recent TRB Paper
COMMENTS?
81
Example I.7 – Estimating Reliability
EXAMPLE I.8 –TRANSIT, BIKE,
PED LOS
• Objective:
• To screen for multimodal LOS problems in highway system
• Procedure:
• Step 1: Select transit, bike, ped service volume tables
• Step 2: Screen for transit LOS problems
• Step 3: Screen for bicycle LOS problems
• Step 4: Screen for pedestrian LOS problems
• Interpretation of Results
82
• Agency policies vs. LOS
TRANSIT LOS
The most important factor = Frequency of Service
Next most important factor = Speed of Transit
Bus Frequency
LOS A-C
LOS D
LOS E
LOS F
1 bus/hr
N/A
N/A
>35 mph
<30 mph
2 buses/hr
>25 mph
10-25 mph
3-10 mph
<3 mph
3 buses/hr
>11 mph
4-11 mph
<4 mph
N/A
4 buses/hr
>7 mph
2-7 mph
<2 mph
N/A
83
Other factors = pedestrian environment, bus stop amenities
TRANSIT SERV. VOL. TABLE
Buses/h
Speed Limit
(mi/h)
LOS A-C
CBD
6
25
790
Urban
4
35
880
Urban
2
35
10
Suburban
2
45
860
Suburban
1
45
N/A
LOS D
LOS E
890
900
N/A
720
84
Area Type
Maximum Directional Auto Volume for
Target Transit LOS (veh/h/ln)
BICYCLE & PEDESTRIAN LOS
• Depends on:
• Geometric Characteristics
•
Bike lane, sidewalks, buffer strip, etc.
85
• Auto Volume
• Auto Speed
• Percent Trucks
BIKE LOS
Bike
LOS A-C
Bike
LOS D
Bike
LOS E
Bike
LOS A-C
Bike
LOS D
Bike
LOS E
160
700
50
250
v/c>1
150
660
v/c>1
210
v/c>1
v/c>1
330
v/c>1
v/c>1
890
v/c>1
v/c>1
✔
80
350
v/c>1
120
560
v/c>1
330
v/c>1
v/c>1
✔
680
v/c>1
v/c>1
v/c>1
v/c>1
v/c>1
v/c>1
v/c>1
v/c>1
86
Bike
LOS E
25 mph PSL
Bike
LOS D
50% Parking
35 mph PSL
30
✔
✔
45 mph PSL
Bike
LOS A-C
Features
6' Bike lane
Max Auto Volumes (veh/h/ln)
PED LOS
Max Auto Volumes (veh/h/ln)
✔
✔
N/A
10
340
60
390
720
N/A
310
640
360
690
v/c>1
340
670
v/c>1
710
850
v/c>1
410
740
v/c>1
780
v/c>1
v/c>1
670
v/c>1
v/c>1
v/c>1
v/c>1
v/c>1
87
✔
Ped
LOS E
✔
Ped
LOS D
✔
Ped
LOS A-C
✔
✔
Ped
LOS E
✔
Ped
LOS D
✔
25 mph PSL
Ped
LOS A-C
5' Sidewalk
6' Buffer
50% Parkg
6' Bike lane
55 mph PSL
MULTIMODAL LOS ISSUES
• What should be transit, bike, ped LOS when agency policy
is not to provide for those services
• Low density areas
• How to estimate multimodal LOS when auto volumes
make little or no difference?
• Code basic cross-sectional characteristics into demand
model links
•
Presence of bike lanes, parking, buffer strip, sidewalk
88
• Use GIS, color code links by LOS
BIKE SYSTEM
LOS MAP
• These are routes where
agency would like to
provide good Bike LOS.
89
• This is how they rated.
COMMENTS?
90
Example I.8 – Transit, Bike, Ped LOS
EXAMPLE I.9 – TRUCK LOS
• Objective: To identify truck level of service problem
facilities within the highway system.
• Procedure:
Step 1: Select truck LOS table
Step 2: Assign links to truck LOS table entries
Step 3: Tally truck LOS results
Step 4: Interpretation of results
91
•
•
•
•
TRUCK LOS
• Depends on :
•
•
•
•
Peak hour truck speed (recurring congestion)
Probability of on-time arrival (reliability)
Tolls
Truck friendliness index
•
•
Percent of legal loads and vehicles that can use facility
Number of at-grade railroad crossings
• Goods movement functional class of facility
Inter-regional facility
Primary regional facility
Supporting facility (feeds intermodal terminals)
92
•
•
•
FFS = 55-75 mi/h
Freeways and
Rural Highways
TRUCK TTI LOS LOOKUP
Truck TTI
95% TTI
POTA
%Ideal
Class I
Class II Class III
1.05
1.18
99%
90%
A
A
A
1.10
1.35
93%
86%
B
A
A
1.15
1.51
81%
76%
C
B
B
1.20
1.67
69%
63%
D
D
C
1.25
1.82
60%
51%
E
E
D
1.30
1.96
53%
41%
F
F
E
1.35
2.10
48%
34%
F
F
F
1.40
2.23
43%
28%
F
F
F
Truck LOS = function of (on-time arrival, travel time, toll, truck friendliness)
93
Tables also for signalized urban streets (35-55 mph speeds)
TRUCK SPEED TO LOS TABLE
Truck Speed
Class I
InterRegional
Class II
Primary
Route
Class III
Supporting
Route
50 mph
D
D
C
45 mph
F
F
E
FFS = 55 mi/h
28 mph
D
C
C
FFS = 45 mi/h
23 mph
D
D
C
FFS = 35 mi/h
17 mph
E
E
D
94
Signalized Urban
Streets
Freeways and
Rural Highways
Link ID
A001
A002
A003
A004
A005
A006
Type
FreewayUrban
ArterialUrban
CollectorUrban
FreewayRural
HighwayRural
CollectorRural
Truck
Demand
(veh/h)
Mixed
TTI
Truck
Speed
Adj
Truck
TTI
Freight
Class
Truck
LOS
411
6.01
1.1
6.61
I
F
122
1.87
1.1
2.06
II
E
47
1.14
1.1
1.26
III
A
279
1.02
1.1
1.12
I
B
119
1.07
1.1
1.17
I
B
15
1.00
1.1
1.10
II
A
95
TRUCK LOS EXAMPLE COMPS
COMMENTS?
96
Example I.9 – Truck LOS
COMMENTS CASE STUDY 1?
• Case Study #1 – Long Range Regional Plan
• What do you like so far?
• What do you dislike?
97
• What is missing?
11:30
98
CASE STUDY #2 – FREEWAY PROJECT
CASE 2 –
FREEWAY MASTER PLAN
• 4-6 Lane Interurban Freeway
• 70 miles long,
• Passes through 5 urban areas
99
• 7% grade over Cuesta Pass
OBJECTIVE
100
To develop a Corridor Mobility Master Plan to identify current
and future mobility problems in the corridor, and establish
capital project priorities along the corridor.
CASE 2 EXAMPLE PROBLEMS
• Example II.1 – Screening for Service Volume Problems
• Example II.2 – Forecasting V/C Hot Spots
• Example II.3 – Estimation of Speed and Travel Time
• Example II.4 – Prediction of Unacceptable Auto LOS Spots
• Example II.5 – Estimation of Queues
101
• Example II.6 – Prediction of Reliability Problems
EXAMPLE II.1 –SCREENING FOR
SERVICE VOLUME PROBLEMS
• Objective:
• To focus the study on critical auto LOS supersections of
freeway
• Approach:
Step 1: Data requirements
Step 2: Categorize facilities
Step 3: Develop service volume look up table
Step 4: Select focus supersections
102
•
•
•
•
SERVICE VOLUME TABLES
• Maximum traffic volumes that can be accommodated at a
target LOS.
• Auto LOS tables
•
Freeway, Multilane Hwy, Two-Lane Hwy, Urban Street
• Bus, Bicycle, Pedestrian LOS tables
• Truck LOS tables
• They hinge on many underlying assumptions
103
• Use as a Screening & Scoping Tool
KFactor
0.08
0.09
0.10
0.11
DFactor
0.50
0.55
0.60
0.65
0.50
0.55
0.60
0.65
0.50
0.55
0.60
0.65
0.50
0.55
0.60
0.65
Four-Lane Freeways
LOS C
LOS D
LOS E
75,500
94,100
108,900
68,700
85,500
99,000
62,900
78,400
90,800
58,100
72,400
83,800
67,100
83,600
96,800
61,000
76,000
88,000
56,000
69,700
80,700
51,600
64,300
74,500
60,400
75,300
87,100
54,900
68,400
79,200
50,400
62,700
72,600
46,500
57,900
67,000
54,900
68,400
79,200
49,900
62,200
72,000
45,800
57,000
66,000
42,300
52,600
60,900
Six-Lane Freeways
LOS C
LOS D
LOS E
113,300
141,100
163,400
103,000
128,300
148,500
94,400
117,600
136,100
87,200
108,500
125,700
100,700
125,400
145,200
91,600
114,000
132,000
83,900
104,500
121,000
77,500
96,500
111,700
90,600
112,900
130,700
82,400
102,600
118,800
75,500
94,100
108,900
69,700
86,800
100,500
82,400
102,600
118,800
74,900
93,300
108,000
68,700
85,500
99,000
63,400
78,900
91,400
104
FREEWAY SERVICE VOLUME TABLE
Level of Service
Minimum Peak Direction
Volume
Maximum Peak Direction
Volume
LOS A-C
0
1510 veh/h/lan
LOS D
1510 veh/h/ln
1880 veh/h/ln
LOS E
1880 veh/h/ln
2180 veh/h/ln
LOS F
2180 veh/h/ln
infinity
105
FREEWAY SERVICE VOLS
DATA REQUIREMENTS
•
Data
•
• Facility Type (freeway, highway)
• Area type (urban, rural)
• Terrain type (level, rolling, mountain)
• AADT
• K-factor (pk.hr/AADT)
• D-Factor (directional factor)
Split Facility into Supersections
Combinations of sections
With similar AADT, area type, terrain
106
•
•
DETERMINE FACILITY TYPE
• Freeway (access controlled)
107
• Multilane highway
SELECT SERVICE VOL TABLE
• First verify HCM service volume tables apply.
Required Data
K-Factor
D-Factor
%Trucks
%Buses
%RVs
PHF
Ramp Density (/mi.)
fp
Lane Width (ft.)
Lateral Clear (ft.)
FFS (mph)
Terrain
Urban Freeways
0.08 – 0.11
0.50 – 0.65
5%
0%
0%
0.95
3
1.00
12
6
65
Level or Rolling
Default Values
Rural Freeways Urban Highways
0.09 – 0.12
0.08 – 0.12
0.50 – 0.65
0.50 – 0.65
12%
8%
0%
N/A
0%
N/A
0.88
0.93
0.2
N/A
0.85
1.00
12
N/A
6
N/A
65
60
Level or Rolling Level or Rolling
Rural Highways
0.09 – 0.12
0.50 – 0.65
12%
N/A
N/A
0.88
N/A
1.0
N/A
N/A
60
Level or Rolling
108
• Adjust DSV (daily service volume) if necessary.
ADJUST FOR LOCAL
CONDITIONS
Local
DSV = 𝑀𝑆𝐹0 ×
HCM Table
𝑁 × 𝑓𝐻𝑉 × 𝑓𝑝 × 𝑃𝐻𝐹
𝐾0 × 𝐷0
×
𝐾×𝐷
𝑁0 × 𝑓𝐻𝑉,0 × 𝑓𝑝,0 × 𝑃𝐻𝐹0
109
Where:
DSVi = daily service volume (veh/day)
MSFi = maximum service flow (vphpl), HCM Exhibit 11-17 for frwys , Exhibit 14-17 for hwys
N = number of lane in each direction
fHV = adjustment factor for presence of heavy vehicles in traffic stream
fp = adjustment factor for unfamiliar driver populations
PHF = peak-hour factor
K = proportion of daily traffic occurring in the peak hour of the day
D = proportion of traffic in the peak direction during the peak hour of the day
IDENTIFY FOCUS
SUPERSECTIONS
Modified Max AADT (x 1,000)
Area
Type
Terrain
Future
AADT
LOS
C
LOS
D
LOS
E
Future
LOS
A
4-ln Highway
Urban
Level
57,600
59,200
75,700
84,100
A-C
B
4-ln Freeway
Urban
Level
63,500
62,900
78,400
90,800
D
C
4-Ln Freeway
Rural
Level
70,100
50,400
62,800
72,700
E
D
4-Ln Freeway
Urban
Level
55,800
61,000
76,000
88,000
A-C
E
6-Ln Highway
Rural
Mountain
44,500
52,500
67,100
74,500
A-C
F
4-Ln Freeway
Urban
Level
58,700
65,800
82,000
94,900
A-C
G
4-Ln Freeway
Urban
Level
58,800
57,900
72,100
83,500
D
H
4-Ln Freeway
Urban
Level
32,400
65,800
82,000
94,900
A-C
I
4-Ln Highway
Rural
Level
19,500
56,400
72,100
80,100
A-C
110
SuperFacility Type
Section
IDENTIFY FOCUS
SUPERSECTIONS
Modified Max AADT (x 1,000)
Area
Type
Terrain
Future
AADT
LOS
C
LOS
D
LOS
E
Future
LOS
A
4-ln Highway
Urban
Level
57,600
59,200
75,700
84,100
A-C
B
4-ln Freeway
Urban
Level
63,500
62,900
78,400
90,800
D
C
4-Ln Freeway
Rural
Level
70,100
50,400
62,800
72,700
E
D
4-Ln Freeway
Urban
Level
55,800
61,000
76,000
88,000
A-C
E
6-Ln Highway
Rural
Mountain
44,500
52,500
67,100
74,500
A-C
F
4-Ln Freeway
Urban
Level
58,700
65,800
82,000
94,900
A-C
G
4-Ln Freeway
Urban
Level
58,800
57,900
72,100
83,500
D
H
4-Ln Freeway
Urban
Level
32,400
65,800
82,000
94,900
A-C
I
4-Ln Highway
Rural
Level
19,500
56,400
72,100
80,100
A-C
111
SuperFacility Type
Section
RESULT: FOCUS
SUPERSECTIONS
Section ID’s
• Focus SuperSections
• B – North of Arroyo Grande
• C – South of San Luis Obispo
• G – South of Paso Robles
• For Rest of this Case Study
• C – South of San Luis Obispo
SB, PM Peak
112
•
COMMENTS?
113
Example II.1 – Use of Service Volumes to screen and scope
planning analysis
EXAMPLE II.2 – FORECASTING
V/C BOTTLENECKS
• Objective:
• To forecast future auto v/c hot spots on facility.
• Approach:
Step 1: Data requirements
Step 2: Selection of defaults
Step 3: Select study boundaries and time periods
Step 4: Identify segment types
Step 5: Estimate free-flow speeds
Step 6: Estimate capacities
Step 7: Assign section demands
Step 8: Compute v/c ratios
Step 9: Interpretation of Results
114
•
•
•
•
•
•
•
•
•
S Higuera St
Los Osos Valley Rd
SELECTED SUPERSECTION C
SECTIONS 1-3
SB US101
25.911
Section #
Section Type
Length (mi)
Number of Lanes
AADT In
AADT Out
K
% HV and buses
FFS
PHF
C1
Basic
0.05
2
41,700
0.08
5.81
default
default
25.86
24.21
C2
Ramps
1.65
2
8,600 On-ramp
500 Off-ramp
0.08
5.81
default
default
23.97
C3
Basic
0.24
2
0.08
5.81
default
default
Ra
1
6,
4,
0
5
115
PM
def
def
Avila Beach Dr
S Higuera St
San Luis Bay Dr
Los Osos Valley Rd
S Higuera St
SB US101
24.21 PM
Section C3
#
SectionBasic
Type
Length 0.24
(mi)
Number 2of Lanes
AADT In
AADT Out
K
0.08
% HV and
5.81 buses
FFS
default
PHF default
23.97 25.911
25.86
22.46
C1
C4
Basic Ramps
0.05 1.51
2
2
41,7006,100 On-ramp
4,600 Off-ramp
0.08 0.08
5.81 5.81
defaultdefault
defaultdefault
22.09
24.21
C2
C5
C6
Ramps
Basic
Ramps
0.37 1.65
0.81
2
2
2
8,600 On-ramp 1,400 On-ramp
500
Off-ramp 1,400 Off-ramp
0.08 0.08
0.08
5.81
5.81
5.81
default default
default default
default
default
21.28
21.105
23
C3
C7
Basic Basic
0.24 0.18
2
2
0.08 0.08
5.81 5.81
defaultdefault
defaultdefault
116
amp
ramp
SELECTED SUPERSECTION C
SECTIONS 4-7
1. DATA REQUIREMENTS
Peak hour factor (peak 15 minutes to peak hour)
Percent heavy vehicles
Peak (K) factor (peak hour to daily)
Segment Type (basis, weave, merge, diverge)
Segment Length
Lanes
Demand (Mainline in, all ramps)
117
•
•
•
•
•
•
•
DEFAULTS
Default Values
K-Factor
Urban Freeways
0.08 – 0.11
Rural Freeways
0.09 – 0.12
D-Factor
0.50 – 0.65
0.50 – 0.65
5%
0%
0%
0.95
1.00
12
6
12%
0%
0%
0.88
0.85
12
6
%Trucks
%Buses
%RVs
PHF
Fp (Driver Population)
Lane Width (ft.)
Lateral Clearance (ft.)
118
Required Data
SELECT STUDY BOUNDARIES
& TIME PERIODS
• Review historical information on congestion
• Select Peak Period and Direction
119
• Pick Southbound Direction, Weekday PM Peak period.
IDENTIFY SECTION TYPES
• Freeway weave section
•
•
•
Starts with on-ramp
Ends with off-ramp AND
Has auxiliary lane between the two ramps
• Freeway ramp section
•
•
Starts with on-ramp, or ends with off-ramp, or both
But no auxiliary lanes between on and off-ramps
• Freeway basic section
Everything else
Basic
Ramp
Basic
1
2
3
Flow
Ramp
Basic
Ramp
Basic
5
6
7
4
No Weave Sections
120
•
ESTIMATE FREE-FLOW
SPEEDS
Use HCM Method
𝑭𝑭𝑺 = 𝟕𝟓. 𝟒 − 𝒇𝑳𝑾 − 𝒇𝑳𝑪 − 𝟑. 𝟐𝟐𝑻𝑹𝑫𝟎.𝟖𝟒
Or Use Posted Speed Limit
𝑭𝑭𝑺 = 𝑷𝑺𝑳 + 𝟓 𝒎𝒑𝒉
121
Where:
FFS = free-flow speed (mi/h)
fLW = adjustment for lane width (mi/h)
fLC = adjustment for right side lateral clearance (mi/h)
TRD = total ramp density (ramps/mi)
PSL = Posted Speed Limit (mi/h)
ESTIMATE CAPACITIES
𝟐, 𝟐𝟎𝟎 + 𝟏𝟎 ∗ 𝐦𝐢𝐧 𝟕𝟎, 𝑺𝑭𝑭𝑺 − 𝟓𝟎
𝒄𝒊 =
𝟏 + %𝑯𝑽/𝟏𝟎𝟎
∗ 𝑪𝑨𝑭
Section #
Type
Length (mi)
Capacity Adjust Factor
Adj Lane Capacity (vphpl)
Number of Lanes
Section Capacity (vph)
C1
Basic
0.05
1.00
2,221
2
4,442
C2
Ramps
1.65
0.95
2,110
2
4,220
C3
Basic
0.24
1.00
2,221
2
4,442
C4
Ramps
1.51
0.95
2,110
2
4,220
C5
Basic
0.37
1.00
2,221
2
4,442
C6
Ramps
0.81
0.95
2,110
2
4,220
C7
Basic
0.18
1.00
2,221
2
4,442
122
Where:
•Ci = capacity of section “I” (vph/ln)
•SFFS = Free-flow speed (mph)
•%HV = percent of heavy vehicles.
•CAF = a capacity adjustment factor that is used to calibrate the basic section capacity given in the HCM to
account for influences of ramps, weaves, or other impacts.
ASSIGN DEMANDS
Compute Section Demands
• If Demand < Capacity
•
•
Sum the mainline in and on-ramp
Subtract off-ramp
• If Demand > Capacity
•
•
•
Do same as before
Reduce demand to capacity
Save up excess demand, add to next time period demand
3,000
3,900
1
2
900
800
3,100
4,100
3,600
3,900
3,100
3
4
5
6
7
1,000
500
300
800
123
Flow
CONSTRAIN DEMANDS
Example for freeway with capacity = 4,000 vph
Flow
Unconstrained
3,900
1
2
900
800
3,100
4,100
3,600
3,900
3,100
3
4
5
6
7
1,000
500
300
800
124
3,000
CONSTRAIN DEMANDS
Example for freeway with capacity = 4,000 vph
Flow
Unconstrained
3,000
3,900
1
2
900
3,100
4,100
3,600
3,900
3,100
3
4
5
6
7
800
1,000
500
300
800
3,000
1
900
3,900
3,100
2
3
800
4,000
100
1,000
4
489
3,511
3,811
3,029
5
6
7
300
782
125
Constrained
COMPUTE D/C AND V/C
• Demand/Capacity ratio
•
Ratio of demand to capacity
• Volume/Capacity Ratio
Ratio of capacity constrained demand to capacity
Section #
Sect. Capacity (Ci)
C1
4,442
Demand (di,1)
D/C Ratio
3,336
0.75
DEMAND (di,2)
D/C Ratio
3,791
0.85
DEMAND (di,3)
D/C Ratio
3,336
0.75
DEMAND (di,4)
D/C Ratio
2,881
0.65
C2
C3
C4
4,220
4,442
4,220
Time Period 1 (16:00-16:15 )
4,024
3,984
4,472
0.95
0.90
1.06
Time Period 2 (16:15-16:30)
4,573
4,175
4,981
1.08
0.94
1.18
Time Period 3 (16:30-16:45)
4,377
4,180
5,429
1.04
0.94
1.29
Time Period 4 (16:45-17:00)
3,632
3,597
5,228
0.86
0.81
1.24
C5
4,442
C6
4,220
C7
4,442
3,852
0.87
3,964
0.94
3,852
0.87
3,802
0.86
3,929
0.93
3,802
0.86
3,852
0.87
3,964
0.94
3,852
0.87
3,902
0.88
3,999
0.95
3,902
0.88
126
•
INTERPRET RESULTS
D/C CONTOUR DIAGRAM
Flow
Contour Diagram
V/C
Period 4
Period 3
D/C
1.50-2.00
1.00-1.50
Period 2
0.50-1.00
0.00-0.50
Period 1
C2
C3
C4
C5
C6
C7
Section
127
C1
COMMENTS?
128
Example Problem II.2 – Auto V/C Bottleneck Identification
EXAMPLE II.3 – ESTIMATION OF
SPEED AND TRAVEL TIME
• Objective:
• To forecast speeds and travel times on freeway.
• Approach:
• Step 1: Estimate delay rates
• Step 2: Compute travel times and speeds
• Step 3: Interpretation of results
Where:
DR = delay rate (secs/mi)
X = volume/capacity ratio
A, B, C, D = parameters
129
𝐷𝑅 = 𝐴𝑥 3 + 𝐵𝑥 2 + 𝐶𝑥 + 𝐷
Section #
FFTravel Rte (s/m)
Length (mi)
C1
55.4
0.05
Delay Rate (s/mi)
Travel Rate (s/m)
Travel Time (sec)
Speed (mph)
1.7
57.0
2.9
62.1
Delay Rate (s/m)
Travel Rate (s/m)
Travel Time (sec)
Speed (mph)
4.8
60.2
3.0
60.0
Delay Rate (s/m)
Travel Rate (s/m)
Travel Time (sec)
Speed (mph)
1.7
57.0
2.9
62.1
C2
C3
C4
55.4
55.4
55.4
1.65
0.24
1.51
Time Period 1 (0-15 minutes)
10.1
6.8
31.3
65.5
62.2
86.6
108.1
14.9
130.8
54.9
58.0
41.6
Time Period 2 (15-30 minutes)
36.3
9.2
67.2
91.6
64.6
122.6
151.2
15.5
185.1
39.3
55.7
29.4
Time Period 3 (30-45 minutes)
23.6
9.3
98.8
79.0
64.7
154.2
130.3
15.5
232.9
45.6
55.7
23.3
C5
55.4
0.37
C6
55.4
0.81
C7
55.4
0.18
5.4
60.8
22.5
59.2
9.2
64.6
52.3
55.8
5.4
60.8
10.9
59.4
4.9
60.3
22.3
59.7
8.7
64.1
51.9
56.2
4.9
60.3
10.9
59.4
5.4
60.8
22.5
59.2
9.2
64.6
52.3
55.8
5.4
60.8
10.9
59.4
130
SPEED RESULTS
SPEED CONTOUR DIAGRAM
Speed Contour Diagram (mph)
Period 4
60.0-70.0
Period 3
50.0-60.0
40.0-50.0
Period 2
30.0-40.0
20.0-30.0
10.0-20.0
C1
C2
C3
C4
Section
C5
C6
C7
0.0-10.0
131
Period 1
COMMENTS
132
Example Problem II.3 – Freeway Speed and Travel Time
Estimation.
EXAMPLE II.4 –UNACCEPTABLE
AUTO LOS HOT SPOTS
Objective:
To predict auto LOS problems
Approach:
Step 1: Estimate density and auto LOS
Step 2: Interpretation of results
133
𝑉𝑜𝑙𝑢𝑚𝑒/𝐿𝑎𝑛𝑒
𝑆𝑝𝑒𝑒𝑑
Density = 1.2*
Level of Service
A
B
C
D
E
F
Freeway Segments
Density (pc/mi/ln)
<= 11
>11-18
>18-26
>26-35
>35-45
>45 or v/c>1.00
COMMENTS?
134
Example Problem II.4 – Freeway Auto LOS Analysis
EXAMPLE II.5 – ESTIMATION
OF QUEUES
• Objective:
• To forecast queuing problems on freeway.
• Approach:
Section Number
Length (mi.)
Number of Lanes
𝐷𝑒𝑚𝑎𝑛𝑑 −𝐶𝑎𝑝𝑎𝑐𝑖𝑡𝑦
)
𝐷𝑒𝑛𝑠𝑖𝑡𝑦
1
2
3
4
5
6
7
0.05
1.65
0.24
1.51
0.37
0.81
0.18
2
2
2
2
2
2
2
4,442
4,220
4,442
Section Capacity (vph)
4,442
4,220
4,442
4,220
Time Period 1 (0-15 minutes)
Demand (vph)
3,336
4,024
3,984
4,472
3,852
3,964
3,852
V/C Ratio
0.75
0.95
0.90
1.06
0.87
0.94
0.87
Density (vpmpl)
26.9
36.6
34.4
50.8
32.5
35.5
32.4
Estimated Queue (mi.)
Actual Queue (mi.)
2.48
0.73
0.24
1.51
135
𝑄𝑢𝑒𝑢𝑒 𝑓𝑡 = 𝑀𝑎𝑥 0,
COMMENTS?
136
Example Problem II.5 – Freeway Queuing Analysis
EXAMPLE II.6 – PREDICTION
OF RELIABILITY PROBLEMS
•
Objective:
•
• To forecast reliability for freeway.
Approach:
Step 1: Data requirements
Step 2: Identify segment types
Step 3: Identify demand variability
Step 4: Identify weather events
Step 5: Identify incidents
Step 6: Identify work zones
Step 7: define reliability analysis scenarios
Step 8: Compute hourly travel times
Step 9: Compute reliability statistics
Step 10: Interpret results
137
•
•
•
•
•
•
•
•
•
•
Data Type
Volume (AADT)
Number of lanes
Length (miles)
K-Factor
D-Factor
Seasonal Adjustment Factor
Work Zone Capacity (vphpl)
Incident Capacity Reduction
Work Zone Avg. Lane Closes
Rainfall Intensity (inches)
Avg. Blocking Incident Duration (minutes)
Avg. Non-blocking Incident Duration (minutes)
Total Number of Blocking Incidents
Total Number of Non-blocking Incidents
Free-flow Speed Reduction for Light-Rain
Free-flow Speed Reduction for Heavy-Rain
Area Type
Analysis Period
Facility Type
Input or
Default Values
Input
Input
Input
Input
Input
Input
1,600
Input
1
Input
Input
Input
Input
Input
6.00%
12.00%
Input
Input
Input
Data Source
Caltrans/Travel Model
Aerial Map
Caltrans/Aerial Map
Caltrans
Caltrans
Caltrans
HCM Exhibit 10-14
HCM Exhibit 10-17
Default
Weather Underground
Caltrans
Caltrans
Caltrans
Caltrans
Default
Default
Local Knowledge
Local Knowledge
HCM
138
DATA FOR RELIABILITY
ANALYSIS
RELIABILITY RESULTS
Computed 95%TTI
Section
Daily
AM (7-9)
PM (4-6)
C1
1.10
1.12
1.14
C2
1.89
1.89
1.75
C3
1.07
1.08
1.14
139
Good, Bad, or Ugly?
RELIABILITY RESULTS(2)
Computed 95%TTI
Section
Daily
AM (7-9)
PM (4-6)
C1
1.10
B
1.12
B
1.14
B
C2
1.89
E
1.89
E
1.75
D
C3
1.07
A
1.08
B
1.14
B
Good, Bad, or Ugly?
Level of
Service
A
B
C
D
E
F
5% Speed
95% TTI
>60 mi/h
55-60
45-55
35-45
25-35
<=25
<1.08
1.08-1.18
1.18-1.44
1.44-1.86
1.86-2.60
>= 2.60
140
Draft FDOT LOS Scale
COMMENTS?
141
Example Problem II.6 – Freeway Reliability Analysis
COMMENTS CASE STUDY 2?
• Case Study #2 – Freeway Master Plan
• What do you like so far?
• What do you dislike?
142
• What is missing?
14:00
143
CASE STUDY #3 – URBAN STREET BRT
CASE 3 –
URBAN STREET BRT PLAN
• 14 mile urban street
144
• BRT to take 2 thru lanes
OBJECTIVE
145
to identify the traffic, transit, pedestrian, and bicycle impacts
of the proposed BRT project.
CASE 3 EXAMPLE PROBLEMS
• Example III.1 – Screening for Service Volume Problems
• Example III.2 – Screening for Auto Choke Points
• Example III.3 – Forecasting V/C Ratios
• Example III.4 – Auto and BRT Speeds/Travel Times
• Example III.5 – Predicting Queues
• Example III.6 – Predicting Reliability Problems
146
• Example III.7 – Transit, Bicycle, Pedestrian LOS
EXAMPLE III.1 –SCREENING FOR
SERVICE VOLUME PROBLEMS
• Objective:
• To focus the study on critical auto LOS supersections of
BRT project
• Approach:
Step 1: Divide BRT route into supersections
Step 2: Obtain AADTs
Step 3: Identify service volumes
Step 4: Identify supersections for further analysis
147
•
•
•
•
DIVIDE BRT ROUTE INTO
SUPERSECTIONS
• Divide route into supersections
• Divide at points where there are significant changes in:
Posted speed limit
Number of through lanes
Median
Demand
148
•
•
•
•
Length
(mi)
AADT
Speed
Limit
(mi/h)
Lanes +
Median
Street
Limits
Telegraph Ave.
Dwight to Woolsey
0.84
16,570
25
4
Telegraph Ave
Woolsey to SR 24
0.80
18,340
30
4
Telegraph Ave
SR 24 to 45th St.
0.60
16,540
30
5
Telegraph Ave
45th St. to Broadway
2.01
16,230
25
5
International Bl.
Lake Merritt to 23rd Ave
1.58
10,220
30
4
International Bl.
23rd Ave to 35th Ave.
0.87
13,370
25
4
International Bl.
35th Ave to High St.
0.51
15,910
25
5
International Bl.
High St. to Hegenberger
1.78
13,560
30
5
International Bl.
Hegenberger to 98th Ave.
1.37
14,830
30
5
International Bl.
98th Ave to Dutton
1.06
11,180
30
5
149
SUPERSECTIONS
SIGNALIZED STREET
SERVICE VOLUME TABLE
K Factor
0.09
0.10
0.11
0.09
0.10
0.11
Four-Lane Streets
D Factor
LOS C
LOS D
LOS E
Posted Speed = 30 mi/h
LOS C
LOS D
LOS E
0.55
0.60
0.55
0.60
0.55
0.60
5,900
5,400
5,300
4,800
4,800
4,400
15,400
19,900
14,100
18,300
13,800
17,900
12,700
16,400
12,600
16,300
11,500
14,900
Posted Speed = 45 mi/h
11,300
10,300
10,100
9,300
9,200
8,400
31,400
28,800
28,200
25,900
25,700
23,500
37,900
34,800
34,100
31,300
31,000
28,400
0.55
0.60
0.55
0.60
0.55
0.60
10,300
9,400
9,300
8,500
8,400
7,700
21,400
19,600
19,300
17,700
17,500
16,100
37,200
34,100
33,500
30,700
30,500
27,900
37,900
34,800
34,100
31,300
31,000
28,400
18,600
17,100
16,800
15,400
15,300
14,000
19,900
18,300
17,900
16,400
16,300
14,900
150
Two-Lane Streets
SERVICE VOLUME TABLES
BACKING
Service Volume Tables are backed by a long list of assumptions:
General assumptions for urban street table:
•
Coordinated, semi-actuated traffic signals;
•
•
no restrictive median; 2-mi facility length; 10% of traffic turns left and
10% turns right at each traffic signal;
•
Peak hour factor = 0.92; and base saturation flow rate = 1,900 pc/h/ln.
•
For 30-mi/h facilities: signal spacing = 1,050 ft and 20 access points/mi.
•
For 45-mi/h facilities: signal spacing = 1,500 ft and 10 access points/mi.
•
(Adapted from Exhibit 10-8, 2010 HCM)
151
•
arrival type 4; 120-s cycle time; protected left-turn phases; 0.45 weighted
average g/C ratio;
Exclusive left-turn lanes with adequate queue storage provided at traffic
signals; no exclusive right-turn lanes provided;
SIGNAL STREET SERV. VOLS
Level of Service
30 mi/h Street
45 mi/h Street
LOS A-C
< 270 veh/h/ln
< 510 veh/h/ln
LOS D
270-760 veh/h/ln
510-890 veh/h/ln
LOS E
760-900 veh/h/ln
890-900 veh/h/ln
LOS F
> 900 veh/h/ln
> 900 veh/h/ln
Entries are Peak Direction, Peak Hour volumes
averaged across through lanes in peak direction
152
A two lane street (one lane each direction) may be able to carry
About 10% more volume before going from LOS E to F.
Before BRT
Street
Limits
After BRT
Lanes
Max LOS
D
Lanes
Max LOS
D
Further
Analysis
?
AADT
Telegraph Ave.
Dwight to Woolsey
16,570
4
28,200
2
13,800
Yes
Telegraph Ave
Woolsey to SR 24
18,340
4
28,200
2
13,800
Yes
Telegraph Ave
SR 24 to 45th St.
16,540
5
28,200
3
13,800
Yes
16,230
5
28,200
3
13,800
Yes
10,220
4
28,200
2
13,800
No
13,370
4
28,200
2
13,800
No
15,910
5
28,200
3
13,800
Yes
13,560
5
28,200
3
13,800
No
14,830
5
28,200
3
13,800
Yes
11,180
5
28,200
3
13,800
No
Telegraph Ave
International Bl.
International Bl.
International Bl.
International Bl.
International Bl.
45th St. to
Broadway
Lake Merritt to 23rd
Ave
23rd Ave to 35th
Ave.
35th Ave to High
St.
High St. to
Hegenberger
Hegenberger to
98th Ave.
International Bl. 98th Ave to Dutton
153
SERVICE VOLUME
SCREENING
FOR FURTHER ANALYSIS
• 6 out of 10 supersections selected for further analysis.
• For rest of case study will focus on one supersection.
Street
Limits
Telegraph SR 24 to
Ave
45th St.
After BRT
Length
(mi)
AADT
Posted Speed
Limit (mi/h)
Lanes
Max
LOS D
Lanes
Max
LOS D
0.60
16,540
30
5
28,200
3
13,800
154
Before BRT
COMMENTS?
155
Example Problem III.1 – Urban Street Screening Analysis
EXAMPLE III.2 – SCREENING
FOR V/C HOT SPOTS
• Objective:
• To identify future auto v/c hot spots for further analysis.
• Approach:
• Step 1: Obtain data
• Step 2: Compute critical lane volumes
• Step 3: Interpretation of results
• V/C hot spots usually at signalized intersections
Can be other major intersections.
156
•
157
DATA
SUM UP CRITICAL LANE VOLS
• Convert all turn moves to equivalent per lane volumes
• Find Maximum North-South street critical lane volume
• NB Left + SB Thru
• SB Left + NB Thru
• Find Maximum East-West street critical lane volume
• EB Left + WB Thru
• WB Left + EB Thru
• Sum up maximum critical lane volumes
• Compare to 1500
158
• If sum of critical lane volumes > 1500, further analysis…
CRITICAL LANE ANALYSIS
NBL+
SBT
SBL +
NBT
Max
N/S
EBL+
WBT
WBL+
EBT
Max
E/W
Critical
Is it
Sum <1500?
Telegraph 45th St
509
715
715
252
290
290
1005
OK
Telegraph 48th St
505
668
668
55
55
55
723
OK
Telegraph 49th St
611
932
932
123
123
123
1055
OK
Telegraph 51st St
636
1018
1018
710
466
709.5
1728
Not OK
Telegraph Claremont
794
582
794
160
136
160
954
OK
Telegraph 55th St
914
920
920
425
425
425
1345
OK
159
E/W
N/S Street Street
INTERPRETATION
• Critical lane analysis overlooks a lot of subtleties.
• Left turn protection is treated same as permitted
• Heavy truck volumes, narrow lanes, parking interference
• Pedestrian crossing constraints ignored.
• It tells you where there may be problems, but not if there
are problems.
• It may miss non-standard problems.
160
• For rest of Case Study will focus on the one intersection
that failed the critical lane check: Telegraph and 51st St.
COMMENTS?
161
Example Problem III.2 – Intersection Screening Analysis
EXAMPLE III.3 –
INTERSECTION V/C
• Objective:
• To forecast intersection volume/capacity ratios.
• Taking into account more factors than critical lane.
• Approach:
Step 1: Required data
Step 2: Determine left turn phasing
Step 3: Convert turns to pce’s
Step 4: Assign volumes to lane groups
Step 5: Calculate critical lane group volumes
Step 6: Compute intersection v/c
162
•
•
•
•
•
•
INTERSECTION V/C INPUT
Med
Protected
Med
Protected
LT
91
1
0.92
0.05
WB
TH
582
2
0.92
0.05
Yes
Med
Protected
RT
111
Med
Protected
163
Volume
Lanes
PHF
% HV
Parking
activity
Ped activity
LT phasing
LT
83
1
0.92
0.05
Signalized Intersection Planning Method, Input Worksheet (Part 1)
Telegraph Avenue and 51st Street
NB
SB
EB
TH
RT
LT
TH
RT
LT
TH
RT
794
59
283
505
22
294
763
80
1
1
1
2
2
0.92
0.92
0.92
0.92
0.92
0.05
0.05
0.05
0.05
0.05
Yes
Yes
Yes
INTERSECTION V/C OUTPUT
Signalized Intersection Planning Method, Calculations (Part 1)
Telegraph Avenue and 51st Street
RT
Check #1
LT<200
Check #2
Not exceed a given Threshold
Check #3
LT phasing
EHVadj
EPHF
ELT
ERT
EP
ELU
vadj
vi (pc/h/ln)
vcEW
vcNS
vc
vc/ci
Intersection
sufficiency
1 LT lane
Protected
1.05
1.09
1.05
1.09
LT
Exceed a given Threshold
909
95
1014
RT
LT
Exceed a given Threshold
105
1.3
1.2
324
324
1.05
1.03
1.05
607
39
347
917
Step 3. Assign volumes to lane groups
646
174
530
Step 4. Calculate critical lane groups
vcNS=1338
WB
TH
1.05
1.09
1.3
1.2
143
RT
LT<200
Not Exceed a given
Threshold
1 LT lane
Protected
1 LT lane
2 LT lanes
Protected
Protected
Step 2. Convert turning movements to passenger car equivalents
1.05
1.05
1.05
1.05
1.05
1.05
1.05
1.05
1.09
1.09
1.09
1.09
1.09
1.09
1.09
1.09
1.3
1.2
95
SB
EB
TH
RT
LT
TH
Step 1. Determine LT phasing
LT>200
LT>200
1.05
1.09
1.3
1.2
104
1.05
699
104
449
198
vcEW =634
1972
Step 5. Intersection volume-to-capacity ratio
1.20 (Use Default ci=1650 pc/h/ln)
Over Capacity
164
LT
NB
TH
COMMENTS?
165
Example Problem III.3 – Intersection V/C Analysis
EXAMPLE III.4 – ESTIMATE
SPEEDS FOR AUTO AND BRT
• Objective:
• To predict auto and BRT speeds
• Approach:
Step 1: Estimate midblock free-flow speeds
Step 2: Estimate intersection delays
Step 3: Check for mid-block delays
Step 4: Compute segment speed
Step 5: Estimate BRT speed
Step 6: Aggregate to facility level
166
•
•
•
•
•
•
ESTIMATE AUTO SPEED
3600 𝐿𝑖
𝑇𝑖 =
+ 𝑑𝑖𝑛𝑡 + 𝑑𝑚𝑏
𝐹𝐹𝑆
3600 𝐿𝑖
𝑆𝑖 =
𝑇𝑖
Auto speed = 7.4 mph
LOS = F
167
Where:
Ti = travel time segment “I”
Li = length of segment
Dint = delay at intersection
Dmb = mid-block delay
Si = average speed segment “I”
ESTIMATE BUS SPEED
𝑇𝑖,𝑏𝑢𝑠
5,280 𝐹𝐹𝑆
=
+ 𝑑𝑖𝑛𝑡,𝑏𝑢𝑠 + 𝑑𝑚𝑏 + 𝑑𝑏𝑠
3,600 𝐿𝑖
where
=
=
=
=
=
=
=
=
base bus travel time for segment i (s),
midblock free-flow speed from Equation H-1 (mi/h),
number of feet per mile,
number of seconds per hour,
Length of segment i (ft),
average bus traffic signal delay not part of dwell time (s),
midblock bottleneck delay (if any) (s), and
total bus stop delay in the segment (s).
Bus Speed = 20.3 mph
At frequency = 4/hr, LOS = A-C
168
Ti,bus
FFS
5,280
3,600
Li
dint,bus
dmb
dbs
COMMENTS?
169
Example Problem III.4 – Auto and Bus Speed Analysis
EXAMPLE III.5 – ESTIMATION
OF QUEUES
• Objective:
• To forecast queuing problems on street.
• Approach:
𝐴𝑣𝑒𝐷𝑒𝑙𝑎𝑦 ∗ 𝐶𝑎𝑝𝑎𝑐𝑖𝑡𝑦
𝑄𝑢𝑒𝑢𝑒 =
3600
Signalized Intersection Planning Method - Queue Calculations
RT
LT
269
52
4
SB
TH
839
28
7
RT
LT
95
57
2
EB
TH
443
46
6
RT
LT
95
57
2
WB
TH
443
46
6
RT
170
Capacity (veh/h)
Ave Delay (s)
Ave Queue (veh)
LT
269
47
4
NB
TH
839
33
8
COMMENTS?
171
Example Problem III.5 – Urban Street Queue Analysis
EXAMPLE III.6 –
PREDICT RELIABILITY
•
Objective:
•
• To forecast reliability for urban street.
Approach:
Step 1: Data requirements
Step 2: Identify segment types
Step 3: Identify demand variability
Step 4: Identify weather events
Step 5: Identify incidents
Step 6: Identify work zones
Step 7: Define reliability analysis scenarios
Step 8: Compute hourly travel times
Step 9: Compute reliability statistics
Step 10: Interpret results
172
•
•
•
•
•
•
•
•
•
•
RELIABILITY RESULTS
Congested with rain and work zone
Congested with rain, incident, work zone
Congested with work zone
Congested with incident and work zone
Congested with rain and incident
Congested with incident
Non-congested with rain and work zone
Non-congested with rain, incident, work zone
Non-congested with rain and incident
Non-congested with work zone
Non-congested with incident and work zone
Non-congested with incident
Non-congested with rain
No Congestion, No Rain, No Incident, No Work Zone
Weekday PM Peak Hours of the Year
Probability
0.18%
0.00%
0.27%
0.00%
0.40%
0.60%
0.01%
0.00%
0.02%
0.03%
0.00%
0.07%
38.27%
60.14%
Speed
(mph)
5.9
5.9
6.0
6.0
6.0
6.2
14.0
14.0
14.2
14.7
14.7
14.9
15.0
15.8
95% TTI = 2.34
173
Different Scenarios During PM Peak Hour
COMMENTS?
174
Example Problem III.6 – Urban Street Reliability Analysis
EXAMPLE III.7 – TRANSIT,
BIKE, PED LOS
• Objective:
• To forecast transit, bike, ped LOS.
• Procedure:
Step 1: Data requirements
Step 2: Compute transit LOS
Step 3: Compute bicycle LOS
Step 4: Compute pedestrian LOS
In Progress
175
•
•
•
•
COMMENTS SO FAR?
• Case Study #3 – BRT Planning
• What do you like so far?
• What do you dislike?
176
• What is missing?
14:45
177
CASE STUDY #4 – SYSTEM MONITORING
CASE 4 – SYSTEM
MONITORING
• State produces annual report on state highway system
performance.
• Over 12,000 center-line miles,
• 28,000 directional segments
• Three different monitoring station types
178
• Some collect AADT only (e.g. HPMS)
• Some collect Hourly speed data only (e.g. INRIX)
• Some collect simultaneous hourly spot speeds and
volumes (loop detectors)
CASE 4 – EXAMPLE
PROBLEMS
For All System Performance Monitoring Sites
• Example IV.1 – Estimate Site Capacities & Free-Flow Speeds
For Volume Only Monitoring Sites
• Example IV.2– Estimate Site Speeds from Volumes
For Travel Time Only Monitoring Sites
• Example IV.3 – Estimate Site Volumes from Speeds
For All Performance Monitoring Systems
179
• Example IV.4 – HCM Assisted QA/Quality Control
• Example IV.5– Computation of Modal Performance Measures
EXAMPLE PROBLEM IV.1 –
SITE CAPACITIES AND FFS
Objective:
• Need monitoring site capacities and free-flow speeds to
compute various performance measures.
Approach:
180
• Use same method as used in areawide studies to develop
capacity and free-flow speed look up tables by facility type
and area type.
Free-Flow Speed
(mph)
Capacity
(veh/ln)
Downtown
55
1800
Urban
60
1800
Suburban
65
1900
Rural
70
1900
Downtown
25
700
Urban
35
700
Suburban
45
600
Rural Multi-Lane
55
1700
Rural 2-Lane
55
1300
Downtown
25
600
Urban
30
600
Suburban
35
600
Rural Multi-Lane
45
1500
Rural 2-Lane
45
1300
Facility Type
Freeway
Arterial
Collector
Area Type
181
CAPACITY AND FFS TABLE
EXAMPLE IV.2 – ESTIMATE
SPEEDS FROM VOLUMES
Objective:
• To estimate speeds for sites that collect only volume data.
Approach:
182
• Use Akcelik equation to compute speed from v/c ratio and
free-flow speed.
INPUT
Length
(mi)
Lanes
AADT
K
D
Facility
Type
Area
Type
Pk Hr
(veh/h)
PkDir
(veh/h)
0.85
8
175,800
0.085
0.55
Freeway
Urban
14,940
8,220
A002
0.21
6
34,500
0.092
0.55
Arterial
Urban
3,170
1,740
A003
1.34
4
22,700
0.094
0.55
Collector
Urban
2,130
1,170
A004
2.50
4
53,400
0.095
0.55
Freeway
Rural
5,070
2,790
A005
4.50
4
28,200
0.096
0.55
Highway
Rural
2,710
1,490
A006
7.30
2
4,600
0.098
0.55
Collector
Rural
450
250
Site ID
183
A001
Length
(mi)
Type
Free Spd
(mi/h)
Cap/Ln
J
Cap
v/c
Spd (mi/h)
A001
0.85
Frwy-Urb
60
1800
8.40E-06
7,200
1.14
10.0
A002
0.21
Art-Urb
35
700
9.34E-06
2,100
0.83
18.7
A003
1.34
Coll-Urb
30
600
9.34E-06
1,200
0.98
26.2
A004
2.50
Frwy-Rural
70
1900
1.99E-05
3,800
0.73
68.7
A005
4.50
Hwy-Rural
55
1700
9.34E-06
3,400
0.44
51.5
A006
7.30
Coll-Rural
45
1300
2.31E-05
1,300
0.19
44.8
Site ID
184
ESTIMATED SPEEDS
COMMENTS?
185
Example Problem IV.2 – Estimating Speeds from Count Data
EXAMPLE IV.3 – ESTIMATE
VOLUMES FROM SPEEDS
Objective:
• To estimate volumes to associate with measured speeds.
Approach:
• Back solve Akcelik equation to determine volumes from
measured speeds.
A
T  T0
0.25H
16 J * L2
B
H2
Where:
x = the link demand/capacity ratio;
A= composite variable defined at left.
B = composite variable defined at left.
T = link travel time (h),
To = link travel time at free-flow link speed (h),
H = the expected duration of the demand (typically one hour) (h);
x = the link demand/capacity ratio;
L= the link length (mi).
J = the calibration parameter
186
A2  2 A
X 
B  2A
Site ID
A001
A002
A003
A004
A005
A006
Length
Lanes
Spd (mi/h)
Facility
Type
Area Type
K
D
0.85
8
10.0
Freeway
Urban
0.085
0.55
0.21
6
18.7
Arterial
Urban
0.092
0.55
1.34
4
26.2
Collector
Urban
0.094
0.55
2.50
4
68.7
Freeway
Rural
0.095
0.55
4.50
4
51.5
Highway
Rural
0.096
0.55
7.30
2
44.8
Collector
Rural
0.098
0.55
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INPUT SPEED MONITOR DATA
ESTIMATED VOLUMES
Type
0.85
0.21
1.34
2.50
4.50
7.30
Frwy-Urb
Arterial-Urb
Collector-Urb
Frwy-Rural
Hiwy-Rural
Collect-Rural
Site ID
A001
A002
A003
A004
A005
A006
Length
0.85
0.21
1.34
2.50
4.50
7.30
Free
Spd
60
35
30
70
55
45
Cap/Ln
J
Cap
A
B
v/c
1800
700
600
1900
1700
1300
8.40E-06
9.34E-06
9.34E-06
1.99E-05
9.34E-06
2.31E-05
7,200
2,100
1,200
3,800
3,400
1,300
0.283724
1.59E-05
0.004776
0.002734
0.001179
0.002341
9.71E-05
6.59E-06
2.68E-04
1.99E-03
3.03E-03
1.97E-02
1.14
0.83
0.98
0.73
0.44
0.19
Type
Freeway-Urban
Arterial-Urban
Collector-Urban
Freeway-Rural
Highway-Rural
Collector-Rural
v/c
1.14
0.83
0.98
0.73
0.44
0.19
Pk Dir
8,220
1,740
1,170
2,790
1,490
250
Pk Hr (2wy)
14,950
3,160
2,130
5,070
2,710
450
AADT
175,900
34,300
22,700
53,400
28,200
4,600
188
Site ID
A001
A002
A003
A004
A005
A006
Length
COMMENTS?
189
Example Problem IV.3 – Estimating Volumes from Speed Data
EXAMPLE IV.4 – HCM
ASSISTED QA/QC
Objective:
To error check monitoring data for aberrations
Approach:
Step 1: compare volumes to capacity
Step 2: compare measured free-flow speeds to HCM
190
Step 3: check consistency of measured speeds and flows
against standard speed-flow curves.
191
BEFORE CALIBRATION
192
AFTER CAPACITY AND SPEED
CALIBRATION
COMMENTS?
193
Example Problem IV.4 – QA/QC of Speed and Volume
Monitoring Data
EXAMPLE IV.5 – MODAL
SYSTEM PERFORMANCE
Objective:
To compute modal system performance measures.
Approach :
Step 1: Compute Auto, truck VMT and PMT
Step 2: Compute % VMT by LOS
Step 3: Compute reliability
Step 4: Compute vehicle-hours of delay
Step 5: Compute vehicle-hours in queue
Step 6: Compute v/c
Step 7: Compute % system miles by bike LOS
194
Step 8: Compute % system miles by pedestrian LOS
COMMENTS CASE STUDY 4?
• Case Study #4 – System Monitoring
• What do you like so far?
• What do you dislike?
195
• What is missing?
15:15
196
4. WRAP UP
WRAP UP
1. What do you like the most about the guide & case
studies?
2. What do you dislike the most about the guide & case
studies?
3. What is missing?
197
4. Will you find it useful? Would you recommend it to
others?
NEXT STEPS
-
Guide goes to highway capacity committee January 2015
-
Draft Final goes to panel March 2015.
-
Publication in one year.
198
Next steps:
OUR THANKS TO OUR HOSTS
-
Tom Creasey [email protected]
-
Rick Dowling [email protected]
199
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