Pedestrian Safety At Intersections

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Pedestrian Safety At Intersections

• Assessment of the Walking Security Index - WSI

Safety and Traffic Services 5 February 2003
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Presentation Overview

• Background
• Purposes of WSI
• WSI Formulations
• WSI Report July 1998
• WSI Refinements
• Staff Concerns
• Technical Review
• Vulnerable Road Users

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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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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

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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
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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
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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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WSI Formulations

• Vehicle-Pedestrian Interaction Potential (V-PIP)
• Index
• V-PIP of vehicles/hr x pedestrians/hr
  (1)

• 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
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WSI Formulations

• 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
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WSI Formulations
4. Quality of Infrastructure Condition (QIC)
Index
18 variables pertaining to intersection
construction or maintenance features
(4)

• Its 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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QICI Field Form
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WSI Formulations

• 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
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WSI Formulations
6. Basic Walking Security (BWS) Index
BWS (WPCEPIP) 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. WPCEPIP
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
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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 (redamber)/hr total of
vehicles/hr
(9)
Source Walking Security Index Report (p 75)
Wellar, July 1998
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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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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

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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)

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WSI Refinements
6. Basic Walking Security (BWS) Index
BWS (WPCEPIP) 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
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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
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WSI What is it?

• 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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WSI What does it do?

• 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

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WSI Staff concerns

• We are committed to improving safety for all
  road
• 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

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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

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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

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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

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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

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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

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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

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• Show new design of Laurier/Nicholas

EXISTING GEOMETRY
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Dr. John Robinson
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