Matthew Roe is a Senior Planning and Research Manager for the New York City Department of Transportation. This presentation from August 26, 2013 comes from a seminar on the value of quality data in aiding street design for enhanced public safety. The seminar was hosted by EMBARQ Turkey at the Istanbul Technical University.

1. Data-Driven Design:
State-of-the-Art Street Engineering
Istanbul
26 August 2013

2. • Urban Context & Challenge
• Pedestrian Safety Metrics
• Projects/Design
• Conclusions
future research 2
Today’s Presentation
6,300 mi of streets & highways
781 bridges, 6 tunnels
12,000+ signalized intersections

3. • Needs
– Measure city’s performance
– Prioritize projects/measure facility performance
– Evaluate projects/design changes
3
Measurement Challenges
• Challenges
– “NYC is different”
– Fairness to modes – severity, exposure
– Precision, timeliness
– Work In Real Life

4. • Speed & Arterials
• Likelihood of KSI increases steeply with
increased speed
• Late-night crashes twice as deadly for
pedestrians
• 2/3 of pedestrian fatalities are on arterial streets
(<15% of network)
• Deadly combination: Speeding + midblock/
against signal crossing
• Left Turns & Other Conflicts
– Both one-way and two-way arterials
– 3 times as many pedestrian KSI as right turns
– 47% of pedestrians killed in crosswalks had
right-of-way.
4
Pedestrian Safety Challenges
Academic study of 5 years of
pedestrian KSI cases (NYU/
RPI/SUNY-Buffalo)

5. • National fatality rates are >3x higher than NYC rates
• NYC has low PMT & VMT per capita
– Safer per trip, but more risky per mile.
• Single-mode stats and PMT/VMT stats punish dense, safe urban areas
5
Exposure Matters for City Comparisons
Traffic Fatalities per 100,000 Residents
Yearly Average (2008-2010)
Journey-to-Work
Transit + Walking
Mode Share
(2008-2010)
Pedestrian Non-Pedestrian Total
NYC 1.8 1.4 3.3 68.3%
Peer Cities 2.1 4.4 6.5 26.8%
USA
(less NYC) 1.4 10.2 11.5 8.2%
Sources: NYCDOT, NHTSA FARS, Census ACS 2010 3-year estimates (excl. worked at home)

6. 6
• Divide bicyclist KSI by
indexed commuter bike
volume
• Show improvement in safety
per cyclist
• Not a comparison to other
modes
• Risk indicator important
when use of a particular
mode is changing rapidly
• Similar method could be
used for specific facilities/
sub-city areas if data is
available
Exposure Matters for Growing Modes

7. • KSI per mile over 5-year period (all modes)
– KSI: Persons Killed or Severely Injured.
(Fatalities + “A” Injuries)
– Vulnerable road users more represented than in
total injuries
– More spatiotemporal consistency than fatalities,
but similar crash characteristics
– Reflects crash severity without requiring a
specific weighting system
• High Crash Corridors: top 1/3 of mileage in
each borough
• Allows quick project prioritization
– Corridor safety issues should be addressed at
the corridor level
– Fair to all modes
– KSI/mile represents problem/cost
7
Prioritizing Corridors

8. 8
Information for Planners and Designers
• KSI by mode
• High-Crash
Corridor
designation
• Injuries by
severity by mode
• Map of corridor
• Interface allows project managers to access
safety data quickly, determine priority level

9. • High Crash Locations
prioritized
• Involve communities & local
leaders at depth
commensurate with project
• In-house implementation
• Fast – 6 to 18 months from
initiation to completion
9
Planning & Implementation

10. Monitoring &
Before-After
• Injury crashes
• KSI
• Radar speeds
• Other data:
– Travel Times and/
or LOS
– Community
feedback
– Economic
development
10
Evaluation

11. • Before:
– 60’
– Two lanes each
direction
• After:
– One lane each
direction
– Left turn bays
– Bike lanes or wide
parking lanes (13’)
– Planted refuge
islands
11
Project Type: 4-to-3-Lane Conversion
Empire Boulevard, Brooklyn

12. • Before:
– 50’, two lanes
• After:
– Flush center
median
– Left turn bays
– Bike lanes or
wide parking
lanes
12
Project Type: 2-to-3-Lane Conversion
E. 180th Street, Bronx

13. 13
Project Type: Protected Bike Path
• Before:
– Multi-lane one-way
– Marked bicycle lane
• After:
– Parking-protected
on-street bike path
– Parking lane or
pedestrian plaza
– Left turn bays w/
signal or “mixing
zones”
– Shortened crossings 9th Avenue, Manhattan

14. • Before:
– Mixed traffic
– Lefts vs.
pedestrians
• After:
– Dedicated left
turn signal from
avenue
– Shortened
crossings
14
Project Type: Left Turn Separation
7th Avenue & W. 23rd Street, Manhattan

15. • Before:
– 100’ wide
– Narrow/short islands
– Narrow LT lane
– 3 lanes, narrow right
lane
• After:
– Wider pedestrian
islands
– 2 standard lanes
– Wide parking lane
– Longer/wider LT
lanes
15
Project Type: Center Median Widening
4th Avenue, Sunset Park, Brooklyn

16. • Before:
– Narrow medians
don’t extend into
crosswalk
• After:
– Widened median
tips extend into
crosswalk as
pedestrian
islands
16
Project Type: Arterial Street Median Tips
Queens Boulevard, Queens

17. • Speed limit lowered to 20
mph (from 30)
• Small, self-contained area
• Announced with signs and
gateway treatments
• Self-enforcing speed humps,
parking lane stripes,
standardized lane widths
17
Project Type: Neighborhood Slow Zones
Claremont Slow Zone, Bronx

18. • Measuring Safety
– Use risk per person as comprehensive performance measure
– Use exposure measures useful for fast-growing modes, locations
– KSI or weighted crashes are fair metrics for urban streets
– Need user-friendly data at corridor or intersection level
– Prioritize loosely (strict rankings don’t work in real life)
• Designing with Data
– Problems: Speed, left turns, crossing against signal & midblock
– Designs: removing extra lanes, organizing left turns, reducing time/distance
between crossings
– Implement quickly, learn quickly
18
Conclusions

19. Questions
Matthew Roe
matthewjafferoe@gmail.com
v

20. Decade
NYC
Pedestrian
Fatalities
Avg per Year
Pedestrian
Fatalities per
100,000
Residents per Year
% Pedestrian
1910 – 1919 381 7.3 70%
1920 – 1929 735 11.7 70%
1930 – 1939 693 9.6 70%
1940 – 1949 567 7.4 84%
1950 – 1959 454 5.8 72%
1960 – 1969 434 5.5 60%
1970 – 1979 386 5.2 52%
1980 – 1989 331 4.6 55%
1990 – 1999 261 3.4 51%
2000 – 2009 167 2.0 51%
20
The Century

21. Year
Fatalities
All Modes
Severe
Injuries
All Modes
Pedestrian
Fatalities
Pedestrian
Severe
Injuries
2001 393 5,417 193 1,452
2002 386 5,820 186 1,417
2003 362 5,434 177 1,418
2004 297 4,823 155 1,311
2005 321 4,585 157 1,285
2006 324 4,834 168 1,353
2007 274 4,501 139 1,313
2008 291 4,380 151 1,308
2009 258 4,101 156 1,161
2010 271 4,040 152 1,155
2011 245 4,323* 139 1,160*
21
• 38% reduction in
total traffic fatalities
since 2001
• 28% reduction in
pedestrian fatalities
since 2001
• >20% reduction in
pedestrian and all
severe injuries since
2001
• Goal: 50% reduction
in all fatalities from
2007 to 2030
The Decade
* Preliminary

22. • Population 8.25 m +
• 302 mi2 (783 km2)
• NYC Department of
Transportation:
– 6,300 mi of streets &
highways
– 781 bridges, 6 tunnels
– 12,000+ signalized
intersections
– Staten Island Ferry
– Not subway/bus
operations (MTA)
22
New York City & NYCDOT