Transcript Urban Roadway Congestion - Portland State University

2007 Urban Mobility Report
Principal Speaking Points
Main Points – Congestion Levels
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Congestion is getting worse in areas of all sizes
But, systems are handling much more demand
Congestion levels are related to area population
Operational remedies and public transportation have a
beneficial effect that amounts to about 5 years of growth
• Ops/Public Trans remedies could have 2 to 3 times more
effect if they were more widely deployed.
• Public transportation benefits related to ridership; very
significant in larger areas
Main Points - Strategy Benefits
• Reliability examined in some locations – an emerging
important issue and one that might see more progress
than reducing average congestion levels
• Road growth can reduce congestion
• Operations treatments can also provide benefits but
not to the same level as widened roads
• Public transportation can improve mobility and
reliable travel. Benefit estimates use ridership, but
they do not capture benefits from connecting people
to jobs, schools, etc.
Main Points - Solutions
• Report does not evaluate specific projects or project
types.
• “Solution” is more: capacity, operational treatments,
demand management, land use changes
• The operations treatments “get the most out of the
system that is built” and are proven very cost
effective; they make sense and should be done where
practical and accepted.
• Operations and public transportation benefits are only
estimates using a consistent methodology – local
variations can be significant and you should look at
them to get a complete picture.
• Pricing may have a role where public accepts it.
Main Points - Measures
• Should use multiple measures to evaluate cities &
compare to areas of similar population
• It is more appropriate to use the data at the Urban
Area group level than at the individual area level
• Long-term trends are only available for the
without-strategy set of measures; but they indicate
the general growth of congestion in areas, withstrategy measures are only available in 2000-2005
data
Measure Overview
• Travel Time Index (TTI) – Extra time per minute of
travel; Expressed in ratio to free-flow travel time; 1.3
means a 20 minute trip at the speed limit turns into a
26-minute trip
• Delay per traveler – Extra time added up into annual
amount for peak period travelers; Includes effects of
distance
• Cost – Includes delay and fuel
• Change in measures – Trends are what the measures
and data are best at showing
Study Issues
• There is a Media section on http://mobility.tamu.edu /ums
• Mobility remedy estimates included
– Operational treatments – access management (new), ramp
metering, incident management, signal coordination
– Public transportation & bus/carpool lanes
• Methods are based on ITS Deployment Analysis System
(IDAS) from FHWA and local analysis of projects;
procedures and data described on website
• Associations sponsoring study so that DOT research funds
can be spent on less proven projects; private funds used for
preparing report and printing.
• Pooled fund project will continue to analyze performance
measures and data.
Urban Mobility Report
Texas Transportation Institute
2007
Urban Mobility Report
•
The 2007 report evaluates mobility levels and
travel conditions on the freeway and principal
arterial street networks in urbanized areas from
1982 to 2005 in 85 urban areas.
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Nine basic measures were used to measure
congestion in the urban areas.
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The following is a comparison of mobility levels
in the Oregon urban areas and the average
mobility levels from four population groups in the
85 areas included in the report.
Population
Urban Area
2005 Pop.
(000)
Urban Area
2005 Pop.
(000)
Very Large Area Average
6,023
Medium Area Average
741
Portland (Lrg)
Large Area Average
1,730
1,666
Small Area Average
Eugene (Sml)
Salem (Sml)
321
240
225
Vlg – included in Very Large Area average
Lrg – included in Large Area average
Med – included in Medium Area average
Sml – Included in Small Area average
2005 Delay per Traveler
Urban Area
Hours
Urban Area
Hours
Very Large Area Average
54
Medium Area Average
28
Portland (Lrg)
Large Area Average
38
37
Small Area Average
Eugene (Sml)
Salem (Sml)
17
14
14
Delay per Traveler: Expresses the extra travel time in a ratio with the number of peak
period travelers in the urban area. This measure estimates the amount of time, on
average, each traveler would spend in congested traffic each year. The measure is shown
with operational treatment effects.
2005 Travel Time Index
Urban Area
Travel Time Index
Urban Area
Travel Time Index
Very Large Area Average
1.38
Medium Area Average
1.16
Portland (Lrg)
Large Area Average
1.29
1.24
Eugene (Sml)
Salem (Sml)
Small Area Average
1.10
1.09
1.09
Travel Time Index: Measure of the amount of extra time it takes to travel during the
peak period due to heavy traffic demand and incidents. The travel rate (in minutes per
mile) in the peak is compared to the off-peak, uncongested speeds. A TTI of 1.20
indicates that it will take 20 percent longer to travel to a destination during the peak than
off-peak. The measure is shown with the effects of operational treatments.
2005 Travel Delay
Urban Area
Person-Hours
of Delay (000)
Very Large Area Average
Large Area Average
Portland (Lrg)
169,278
33,809
33,660
Urban Area
Medium Area Average
Small Area Average
Salem (Sml)
Eugene (Sml)
Person-Hours
of Delay (000)
11,087
3,047
1,773
1,766
Travel Delay: The total hours lost due to delay during the peak travel periods is estimated
from travel speed estimates on the freeways and principal arterial streets. Total delay is
related to the speed and the population. These figures include the benefits from operational
treatments.
2005 Delay Savings
Urban Area
Hours (1000)
Oper. P.T.
Urban Area
Very Large Area Avg
14,779 30,681
Medium Area Avg
426
488
Portland (Lrg)
Large Area Average
2,653
2,143
Small Area Average
Eugene (Sml)
Salem (Sml)
86
72
29
89
174
85
6,676
2,558
Delay Savings: Expresses the amount of
delay reduction that occurs due to
enhancements made to the transportation
system.
Hours (1000)
Oper.
P.T.
Oper.—Includes savings due to ramp
metering, incident management, signal
coordination, and access management.
P.T.—Includes savings due to public
transportation and bus/carpool lanes.
2005 Total Congestion Cost
Urban Area
Annual Cost Due
to Congestion ($mil.)
Very Large Area Average
Large Area Average
Portland (Lrg)
3,205
628
625
Urban Area
Annual Cost Due
to Congestion ($mil.)
Medium Area Average
Small Area Average
Eugene (Sml)
Salem (Sml)
206
56
32
31
Congestion Cost: Is estimated by applying hourly values to the amount of travel time delay
and per-gallon estimates of the amount of fuel wasted in congested travel. The areawide
“congestion tax” may be thought of as one expression of the cost of congestion to residents
of an urban area. These figures include the benefits from operational treatments.
2005 Congestion Cost per Traveler
Urban Area
Cost per Traveler
Very Large Area Avg
1,014
Portland (Lrg)
Large Area Average
704
683
Urban Area
Cost per Traveler
Medium Area Average
512
Small Area Average
Salem (Sml)
Eugene (Sml)
318
257
246
Congestion Cost per Traveler: The cost of congestion is estimated with a value for each
hour of travel time and each gallon of fuel. The value of travel time is based on the value
that people demonstrate by their behavior. Paying tolls, erratic lane changing and traffic
citations are some ways motorists illustrate they value their travel time. Fuel cost is
estimated from state averages. These figures include the effects of operational treatments.
2005 Congestion Cost Savings
Urban Area
Annual Savings ($mill.)
Oper.
P.T.
Urban Area
Annual Savings ($mill.)
Oper.
P.T.
Very Large Area Avg
277
578
Medium Area Average
8
9
Portland (Lrg)
Large Area Average
50
40
124
48
Eugene (Sml)
Small Area Average
Salem (Sml)
1
2
1
3
2
2
Congestion Cost: Is estimated by applying
hourly values to the amount of travel time
delay and per-gallon estimates of the amount
of fuel wasted in congested travel. The
areawide “congestion tax” may be thought of
as one expression of the cost of congestion to
residents of an urban area. Cost savings are
due to implementation of operational and
public transportation strategies in each area.
Oper.—Includes savings due to ramp
metering, incident management, signal
coordination, and access management.
P.T.—Includes savings due to public
transportation and bus/carpool lanes.
2005 Wasted Fuel
Urban Area
Total Gallons of
Fuel Wasted (mil.)
Very Large Area Average
Portland (Lrg)
Large Area Average
120
24
23
Urban Area
Total Gallons of
Fuel Wasted (mil.)
Medium Area Average
7
Small Area Average
Eugene (Sml)
Salem (Sml)
2
1
1
Wasted Fuel: The fuel lost due to inefficient operation can be totaled just as the travel
delay is, and the relationship is very similar. Most of the areas have excess fuel
consumption rankings very near to their populations rankings. These figures include the
effects of operational treatments.
2005 Wasted Fuel per Traveler
Urban Area
Gallons per Traveler
Urban Area
Gallons per Traveler
Very Large Area Average
38
Medium Area Average
18
Portland (Lrg)
Large Area Average
27
25
Small Area Average
Eugene (Sml)
Salem (Sml)
10
8
8
Wasted Fuel per Traveler: Expresses the extra fuel consumed due to congestion in a ratio
with peak travelers in the urban area. This is a measure of the effect of slow speeds on the
extra fuel needed each year to travel in congested conditions. These figures include the
effects of operational treatments.
Amount of Capacity Needed Each Year
Urban Area
Lane Miles Needed
Freeway & Prin. Art.
Very Large Area Average
Large Area Average
Portland (Lrg)
301
92
88
Urban Area
Lane Miles Needed
Freeway & Prin. Art.
Medium Area Average
53
Small Area Average
Salem (Sml)
Eugene (Sml)
35
17
8
Amount of Capacity Needed Each Year [to maintain congestion]: The rate of traffic growth
(in percent of additional traffic volume per year) has to equal the rate of freeway and street
expansion (in percent of the system added per year). Comparing the two growth rates, yields
an estimate of the amount of additional road system expansion needed every year to keep a
constant congestion level if traffic continues to grow at the present rate.
Amount of Ridesharing Needed Each Year
Urban Area
Annual Growth in
Trips (million)
Urban Area
Annual Growth in
Trips (million)
Very Large Area Average
356
Medium Average
55
Large Area Average
Portland (Lrg)
109
26
Small Area Average
Salem (Sml)
Eugene (Sml)
31
4
2
Amount of Ridesharing Needed Each Year [to maintain congestion]: The additional
passenger miles of travel are divided by a national average trip length (9 miles) to estimate
number of additional carpool or transit trips that would be needed so that congestion levels
would not increase.
Since You Asked, Here’s Why the Numbers Are Different
Each year the Urban Mobility Report revises procedures and improves the
processes and data used in the estimates. With sponsorship from the
National Cooperative Highway Research Program of the Transportation
Research Board, the methodology was significantly revised in 2006 and
2007 to take advantage of new studies and detailed data sources that have
not been available in previous studies. Some key changes for this year and
their general effects are summarized in Exhibit 2. All of the congestion
statistics in the 2007 Urban Mobility Report have been revised for all years
from 1982 so that true trends can be identified.
• For almost all urban areas that were intensively studied, and for urban
America as a whole, there was more delay, more wasted fuel and higher
congestion cost in 2005 than in 2004. That is the conclusion of this report—
congestion is worse in urban areas of all sizes.
• The revised methodology described below, however, shows that the
estimated speeds on the most congested freeways are better in the 2007
Report than in the 2005 Report. But the year-to-year congestion trends are
still “up.”
• The 2007 report also estimates congestion problems in all urban areas,
instead of only 85 regions. The 352 added regions were mostly small areas
with relatively low congestion levels. Their addition reduces the average
congestion values for each person traveling in the peak period (i.e., a little
more delay and a lot more people), but it also increases the total congestion
estimates (i.e., a lot more people that each have a small amount of delay).
• The benefits from operational treatments and public transportation
likewise appear to decline compared to the 2005 report; the actual numbers
increase if the same methods are used.
More information on the methodology is included on the website at:
http://mobility.tamu.edu/ums/report/methodology.stm
Exhibit 2. Summary – Changes to the 2007 Urban Mobility Report
Change for 2007 Report
Estimate of congestion in all 437 U.S. urban
areas (individual urban area estimates were
only developed for 85 urban areas)
Minor arterial street congestion estimate
High-occupancy vehicle lane statistics
Improve freeway speed estimate
Improve population estimate in some
regions
Use truck percentages for each road
Use average of daily fuel prices for each
state
Seattle region moved to Very Large
population group
General Effect Compared to Previous Reports
Increase the total delay, fuel and cost of
congestion values. Decrease the average “per
traveler” congestion values.
Increase delay, fuel and cost values.
Better estimate of regional congestion
Reduce delay, fuel and cost values. Also caused
lower benefits for operations treatments & public
transportation service (lower initial delay results
in lower delay benefits).
Better estimate of congestion effects on
individuals
Better estimate than previous 5 percent value for
all regions
Better estimate than previous sample of fuel
prices
All historical population group statistics revised to
include Seattle in the Very Large group
Change Highlights—Additions to Congestion Estimates
• National estimate of congestion and costs – The 352 areas that are not
intensively studied were grouped together and congestion estimates were
developed to describe the congestion problem in the nation’s 437 urban
areas. Adding these urban areas increased the total number of peak-period
travelers included in the analysis from 82.1 million in the 85 urban areas to
110.5 million in the 437 urban areas. This change increases the total delay
but, because the smaller areas are much less congested than the large
regions, it reduces the average hours of delay per traveler.
• Minor arterial congestion – As major roads became congested, minor road
traffic volumes have increased. The estimates of congestion are more
complete with these streets included in the arterial category for the 2007
Urban Mobility Report.
• HOV travel – Buses and carpools traveling in reserved lanes provide one
solution that is successful in many urban corridors. In some cases these
lanes can also be used by single travelers who pay a fee. The person volume
and travel speed statistics from operational evaluations in 70 corridors have
been included in the urban area congestion estimates.
Change Highlights—Changes to Congestion Methodology
• Freeway speed estimate – Data from freeway operation centers have
become available in many travel corridors over the last few years.
While the data are not complete enough to use as a direct measure of
congestion in all 85 areas, it was used to update the estimation
procedures. In general, the very low speeds used in previous studies are
not sustained for an entire peak period in most freeway corridors
(Exhibit 4). The detailed data show that freeways carry more vehicles
at higher speeds than models previously estimated. In addition, traffic
growth in the faster flowing off-peak direction has been greater than
growth in the slower speed peak direction. The average traffic speed for
all lanes, therefore, has not declined as much as previous models
predicted. The congestion estimates for all urban areas are lower
because of this change, but in most cases the trends have not changed
from previous studies.
Change Highlights—Changes to Congestion Methodology, cont.
• Population estimate – Urban area populations are not updated by all state
departments of transportation (DOTs) every year in every region. As better
estimates are prepared by local planners, they are incorporated into the
Urban Mobility Report database, even if data from previous years must be
changed.
• Truck percentages for each road – Freight congestion has become a
separate issue in some communities with its own set of solutions. Truck
travel estimates included in the state and local datasets have improved over
the years and have replaced the previous estimate of 5 percent trucks on all
urban roads.
• Average of daily fuel price – The recent fluctuations in gas prices suggested
a need to include more than a small sample of fuel prices. An average of
daily prices in each study state has been developed.
• Seattle region – Regions are grouped according to population. Seattle’s
population is now above 3 million and its statistics are now included in the
Very Large group. As with similar past changes, the Large and Very Large
averages for each statistic and every year have been recalculated with the
new urban area groupings.
Exhibit 4. Freeway Speed – Volume Relationship
Peak Direction
Speed (mph)
70
The 2007 speeds are no lower than
35 mph for the 3-hour peak period.
60
50
40
Speeds are very close in
moderate congestion levels.
2007 Urban
Mobility Report
2005 Urban
Mobility Report
30
20
10
0
14,000
18,000
22,000
Daily Traffic per Lane
26,000
30,000