Transcript Pedestrian Safety At Intersections

Pedestrian Safety At Intersections
Assessment of the
Walking Security
Index - WSI
Safety and Traffic Services – 5 February 2003
Presentation Overview
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Background
Purposes of WSI
WSI Formulations
WSI Report – July 1998
WSI Refinements
Staff Concerns
Technical Review
Vulnerable Road Users
Safety & Traffic Services
5 Feb 2003
Background
• Spawned by public concern for pedestrian safety at
right-turn cut-off ramps at signalized intersections
• At most of these intersections few, if any, collisions
involving pedestrians had been reported; nonetheless,
complaints persisted in response to “close calls”
• Resulted in “A Survey of Pedestrian Concerns and
Attitudes at Right-turn Cut-offs” at Laurier/Nicholas
by Professor Barry Wellar and his students as a class
project in 1994-95
• Results were inconclusive
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5 Feb 2003
Safety & Traffic Services
5 Feb 2003
Background
• WSI concept was formulated by Professor Wellar
and evolved as a “spin off” project from the
Laurier / Nicholas “cut-off ramp” Study
• WSI purpose set out in a 1995 TEAP Project was:
“To define an index to objectively measure
pedestrian security at intersections including
comfort and convenience as well as safety
components”
Safety & Traffic Services
5 Feb 2003
What are the purposes of WSI?
• To provide a means of better describing the walking
security experience of pedestrians at signalized
intersections;
• To provide a means of better explaining why
pedestrians’ experiences differ from their
expectations in regard to security;
Source: Walking Security Index Report (p 32) – Wellar, July 1998
Safety & Traffic Services
5 Feb 2003
Purposes of WSI
• To provide a means of better predicting the
consequences for pedestrians’ security that are likely
to occur as a result of intersection infrastructure
modifications and/or changes in the behaviors of
users; and,
• To provide a means of better evaluating the
consequences for pedestrians’ security that are likely
to arise from proposed modifications to signalized
intersections, infrastructures, and/or to the
behaviors of intersection users.
Source: Walking Security Index Report (p 32) – Wellar, July 1998
Safety & Traffic Services
5 Feb 2003
WSI Formulations:
1. Vehicle-Pedestrian Interaction Potential (V-PIP) Index
V-PIP = # of vehicles/hr x # pedestrians/hr
…(1)
Source: Walking Security Index Report – Wellar, July 1998
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5 Feb 2003
Safety & Traffic Services
5 Feb 2003
Safety & Traffic Services
5 Feb 2003
WSI Formulations:
1. Vehicle-Pedestrian Interaction Potential (V-PIP)
Index
V-PIP = # of vehicles/hr x # pedestrians/hr
…(1)
2. Weighted Vehicle-Pedestrian Interaction
Potential (WV-PIP) Index
WV-PIP = # of vehicles²/hr x # of pedestrians/hr …(2)
Source: Walking Security Index Report – Wellar, July 1998
Safety & Traffic Services
5 Feb 2003
WSI Formulations
3. Weighted Passenger Car Equivalent-Pedestrian
Interaction Potential (WPCE-PIP) Index
WPCE-PIP = # of passenger car equivalents²/hr x
# of pedestrians/hr
…(3)
Where:
automobile = 1.0 passenger car equivalent;
heavy vehicle = 1.7 passenger car equivalent; and,
bus = 1.7 passenger car equivalent.
Source: Walking Security Index Report (p 41 - 47) – Wellar, July 1998
Safety & Traffic Services
5 Feb 2003
WSI Formulations
4. Quality of Infrastructure Condition (QIC) Index
18 variables pertaining to intersection construction
or maintenance features
…(4)
• It’s purpose is to provide an assessment of whether
intersection features involving infrastructure
construction and maintenance meet pedestrians’
security expectations.
Source: Walking Security Index Report (p 47, 48) – Wellar, July 1998
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5 Feb 2003
QICI Field Form
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5 Feb 2003
WSI Formulations
5. Intersection Pedestrian Challenge-Features
(IPC-F) Index
IPC-F = NLR x NTLTR x IGR x ISR x DTFR x NCR
…(5)
Where:
NLR = number of lanes rating
NTLTR = number of lanes by type rating
IGR = intersection geometry rating
ISR = intersection slope rating
DTFR = direction(s) of traffic flow rating
NCR = number of channels adjacent to intersection rating
Source: Walking Security Index Report (p 50 - 68) – Wellar, July 1998
Safety & Traffic Services
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Safety & Traffic Services
5 Feb 2003
WSI Formulations
6. Basic Walking Security (BWS) Index
BWS = (WPCE–PIP) x (IPC-F)
…(6)
Where:
BWS = a composite index score that ranks signalized intersections
according to the likelihood that pedestrians’ security expectations
are matched by experiences.
WPCE–PIP = an index score that represents the quality of potential
interactions between pedestrians or vehicles (expressed as passenger
car units) at signalized intersections.
IPC-F = an index score that represents the magnitude of
challenge to pedestrians’ security caused by intersections’ features.
Source: Walking Security Index Report (p 50 - 70) – Wellar, July 1998
Safety & Traffic Services
5 Feb 2003
WSI Formulations
Aggressive Driving Indexes: (AD_)
(ADR) Index:
Red = # of vehicles through on red/hr
total # of vehicles/hr
…(7)
(ADA) Index:
Amber = # of vehicles through on amber/hr
total # of vehicles/hr
…(8)
(ADRA) Index: Red + Amber = # of vehicles through (red+amber)/hr
total # of vehicles/hr
…(9)
Source: Walking Security Index Report (p 75) – Wellar, July 1998
Safety & Traffic Services
5 Feb 2003
WSI Formulations
Aggressive Driving Fail-to-Yield (ADFY) Index
(ADFY) Index = # of vehicles that fail to yield to pedestrians/hr
total # of vehicles/hr
…(10)
The fail to yield index applies in all those crosswalk and channel
situations where vehicle operators engage in behaviors that
threaten pedestrians’ security:
Source: Walking Security Index Report (p 77) – Wellar, July 1998
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Safety & Traffic Services
5 Feb 2003
Report on WSI - July 1998
• Study resulted in 17 Recommendations
• Staff supported 11 – current policy or were
technically supportable
• Staff could not support the remaining
recommendations - some were contrary to
Highway Traffic Act
Safety & Traffic Services
5 Feb 2003
Report on WSI – July 1998
• Following consideration of the WSI Report, the
researcher presented a proposal to Transportation
Committee, asking that the Study be extended
• Staff were not consulted beforehand
• Committee and Council approved the proposal for a
pilot study that would provide a more robust sample
of field data to refine indexes and variables in WSI
• Field testing was intended to confirm operationality,
not utility
• Resulted in 6 Technical Reports and Final Pilot
Study Report received in May 2002 (Annex 2)
Safety & Traffic Services
5 Feb 2003
WSI Refinements
6. Basic Walking Security (BWS) Index
BWS = (WPCE–PIP) X (IPC-F)
…(6)
Revised to: Intersection Volume and Design (IVDI) Index
IVDI = V1 x V2 x V3 x V4 x V5 x V6 x V7 x V8
Where:
V1 = number of passenger car equivalents /hour
V2 = number of pedestrians/hour
V3 = number of lanes rating
V4 = number of lanes by type rating
V5 = intersection geometry rating
V5 = intersection slope rating
V7 = direction(s) of traffic flow rating
V8 = number of channels adjacent to intersection rating
Safety & Traffic Services
5 Feb 2003
WSI Refinements
Aggressive Driving Indexes: Formulas …(7), (8), (9), (10)
were combined to become: Driver Behaviour Index (DBI)
DBI = ALI + RLI + FTYI
P
P
P
…(11)
Where:
ALI = amber-light incidents per phase,
P
RLI = red-light incidents per phase,
P
FTYI = fail-to-yield incidents per phase,
P
Safety & Traffic Services
5 Feb 2003
WSI …What is it?
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WSI is a composite index
– Intersection Volume and Design Index (IVDI)
– Quality of Infrastructure Condition Index (QICI)
– Driver Behaviour Index (DBI)
Examines 39 variables in four quadrants of each
intersection being reviewed
33 intersections were examined in the Pilot Study
since 1998, resulting in over 200 tables
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5 Feb 2003
WSI …What does it do?
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Purports to describe the walking security
experience of pedestrians at signalized
intersections …but does it?
Purports to provide a score ranking of
pedestrians’ experiences in relation to their
expectations … but does it?
• Example of Ranking …
Safety & Traffic Services
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Safety & Traffic Services
5 Feb 2003
WSI …Staff concerns
• We are committed to improving safety for all road
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users, especially vulnerable road users (pedestrians,
cyclists, seniors, disabled) – WSI does not consider
pedestrian types or cyclists
WSI does not consider collision experience
WSI does not consider pedestrian disregard for
traffic signals
WSI data collection requirements are far too onerous
and costly to perform by City staff
WSI cannot be used to prioritize safety improvements
through any form of cost/benefit analysis
Safety & Traffic Services
5 Feb 2003
WSI …Staff concerns
• WSI does not appear to be technically sound or
legally defensible
• Use of the WSI to rank priorities for roadway
infrastructure modifications for the limited funds
available, could needlessly expose the City
to liability/litigation
Safety & Traffic Services
5 Feb 2003
Why was a Transportation Engineering
Consultant retained to conduct a Technical
Review of the WSI Project?
• To provide an objective, independent, expert
assessment of the WSI with respect to:
• Technical validity
• Mathematical soundness - through examination of:
Indexes on which it is based and
Weighting assigned to index variables
• Defensibility in court should liability issues arise
as a result of WSI
• Data collection and input requirements
Safety & Traffic Services
5 Feb 2003
Why was a Transportation Engineering
Consultant retained to conduct a Technical
Review of the WSI Project?
• To asses the results it produces against outcomes
derived from the application of existing Traffic
Engineering techniques, approved by that
profession as being both cost-effective and sound
engineering practice
Safety & Traffic Services
5 Feb 2003
What are we doing to improve
safety for Vulnerable Road Users?
• Extracting information from over 13,000 Motor Vehicle
Accident Reports annually to maintain an up-to-date
collision database
• Implementing remedial measures at “high collision
locations” and other sites of concern through our
Safety Improvement Program
• Responding to over 7,000 citizen concerns and
service requests for traffic and street lighting
services per year
• Conducting over 800 traffic surveys per year to
address the need for new all-way stop controls,
traffic control signals, pedestrian signals, Adult
Crossing Guards
Safety & Traffic Services
5 Feb 2003
What are we doing to improve
safety for Vulnerable Road Users?
• Providing “Rules of the Road” awareness to children
through our Elementary School Outreach Program
• Providing new sidewalks and recreational pathways
each year
• Providing new cycling lanes as part of all road
construction and intersection modification projects
• Installing audible features at new traffic control
signals installation
• Participating in the Red Light Camera Pilot Project
Safety & Traffic Services
5 Feb 2003
What are we doing to improve
safety for Vulnerable Road Users?
• Learning from experience where right-turn cut-off
ramps should not be constructed, or even considered,
in view of pedestrian activity
• Installing over 20 new traffic control and
pedestrian signals in 2003
• Working in partnership with Police Services and
the Health Department to develop and deliver the
Integrated Road Safety Program, that focuses on the
needs of Vulnerable Road Users
Safety & Traffic Services
5 Feb 2003
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Safety & Traffic Services
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Nicholas Street at Laurier Avenue
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Proposed Geometry
Safety & Traffic Services
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Dr. John Robinson
Safety & Traffic Services
5 Feb 2003
Safety & Traffic Services
5 Feb 2003