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By Shashi Nambisan, Director, CTRE & Professor of Civil Engineering at Iowa State University (Ames, Iowa, USA)
Citation preview
Enhancing Pedestrian Safety: From Theory to Practice
Shashi NambisanDirector, CTRE & Professor of Civil Engineering
Iowa State University (shashi@iastate.edu)
Srinivas Pulugurtha, University of North Carolina, CharlotteMukund Dangeti, University of Nevada, Las VegasVinod Vasudevan, University of Nevada, Las Vegas
Pedestrian Safety and Security for Vulnerable PopulationsEighth Annual Transforming Transportation Workshop
The World BankWorld Resources Institute/EMBARQ
Washington, DCJanuary 15, 2009
Goals
• Improve pedestrian safety, minimize risk
• Identify, develop, deploy and evaluate countermeasures
• Case Study: Las Vegas metro area, Nevada
• Population ~ 1.8 Million
Introduction
• Fastest growing region in the nation
• Wide, fast street grid network High vehicle speeds Long traffic signal cycle lengths
• Pedestrian safety concerns
• Demographics Population ~ 1.8 million Diverse: age, race
• 85 percent of the crashes involved locals
3
Pedestrian Crashes (2003 – 2006)4
Methodology
• Identify candidate locations Site Characteristics Problem Characteristics
• Develop, Deploy, & Evaluate Countermeasures
• Measures of effectiveness
• Site Selection: Excluded the resort Corridor (The “Strip” and its proximity)
5
Study Design
• Before and After Studies
• Comparative Studies (with control group)
• Observations: ~18,000 pedestrians
• Statistical Analyses Parametric Non-Parametric
6
Study Locations
• Top priority / High Risk Locations Crash Index and Crash Rank
• GIS based analysis• 18 locations
includes 4 control locations
• Different Jurisdictions City of Las Vegas City of North Las Vegas Clark County Nevada Dept of Transportation (State)
7
Study Locations
Control PointsHigh Pedestrian Risk Locations
R!
Major Streets0 0.7 1.4 2.10.35Miles /
! !R
R !9 10
13 14 15 16
1817
12 11
! R7 8
!!R
123
R !6 5 4
!!
SAHARA AV
CAREY AV
FLAMINGO RD
TROPICANA AV
WASHINGTON AV
JON
ES
BLV
D
OWENS AVN
ELLIS
BLV
D
CHARLESTON BLVD
DE
CA
TU
R B
LV
D
VEGAS DR
STEWART AV
LAKE MEAD BLVD
PA
RA
DIS
E R
D
BR
UC
E S
T
MA
RY
LA
ND
PK
WY
MA
RTIN
L K
ING
BLV
D
VEGAS VALLEY DR
SMOKE RANCH RD
PE
CO
S R
D
DESERT INN RD
BONANZA RD
TWAIN AV4TH
ST
TWAIN AV
US 95
PE
CO
S R
D
DESERT INN RD
PE
CO
S R
D
8
Selection of Countermeasures
• Site Characteristics Geometric Conditions Operating Conditions Light Conditions Demographics Land-use
• Costs
Countermeasure Types
• Engineering based countermeasures
• ITS based countermeasures
• Others
10
Advanced Warning Signs / Yield Markings11
High Visibility Crosswalk Treatment
12
In-Roadway Knockdown Signs13
Portable Speed Trailer14
Turning Vehicles Yield to Pedestrians
15
Danish Offset and Median Refuge16
Pedestrian Activated Flashers17
Automatic Pedestrian Detection and Smart Lighting
18
Pedestrian Buttons that Confirm Press
19
Pedestrian Channelization20
ITS No-Turn on Red Blank out Signs
21
Pedestrian Countdown Timers with Animated Eyes
22
Measures of Effectiveness / Statistical Tests• Pedestrian
% Using the crosswalk Looking for cars before crossing Captured / Diverted Trapped in the middle of the street Pedestrian-Vehicle Conflicts Pedestrian Waiting for Signal to Cross Delay
• Driver Yielding behavior, distance Blocking crosswalk Speed
23
Speed Trailer Site Information24
Speed Trailer and Vehicle Speeds
35.0
40.0
31.5 31.9
0.0
5.0
10.0
15.0
20.0
25.0
30.0
35.0
40.0
45.0
Direction of Traffic
Av
era
ge
Sp
eed
(m
ph
)
Before After
54.6 kph
50.7 kph
64.3 kph
51.3 kph
25
Speed Trailer: Vehicle Speed Analysis
MOE
Baseline vs. Stage 1 Baseline vs. Stage 2
DeltaMeanSpeed
P-value H0
DeltaMeanSpeed
P-value H0
H0: Vbefore= Vafter vs. Ha: Vafter< Vbefore
Eastbound mph
(kmph)
5.5(8.9)
<0.001 Reject8.1
(13.0)<0.001 Reject
Westbound mph
(kmph)
6.5(10.5)
<0.001 Reject3.7
(6.0)<0.001 Reject
26
Speed Trailer: Analysis of Pedestrians
(Safety) Measures of Effectiveness Baseline Stage 1 Stage 2
Percent Percent Percent
% pedestrians who look for vehicles before beginning to cross
80 100 100
% pedestrians who look for vehicles before crossing 2nd half of street
85 100 100
% pedestrians trapped in the roadway
41 34 37
27
Highly Effective Countermeasures
Description CostAdvanced Yield Markings for Motorists Low
In-roadway Knockdown Signs Low
Pedestrian Countdown Signals with Animated Eyes
Medium
Danish Offset High
Median Refuge High
Portable Speed Trailer High
Pedestrian Activated Flashing Yellow High
28
Moderately Effective Countermeasures
Description CostPedestrian Call buttons that Confirm Press (Visible/Audible confirmation)
Low
Turning Vehicles Yield to Pedestrians Low
ITS No-Turn on Red Signs Medium
ITS Automatic Pedestrian Detection Devices
High
29
Countermeasures with Low Effectiveness
Description CostWarning Signs for Motorists Low
High Visibility Crosswalk Treatment Medium
Pedestrian Channelization* High
Smart Lighting High
30
Summary
• Significant overall benefits Pedestrian Driver
• Permitting & deployment considerations
• Administrative / jurisdictional hurdles
• Vendor / procurement difficulties
• Field observation & data analysis efforts
• Education needs: pedestrians, motorists
31
Comparisons? Opportunities? Constraints?
Acknowledgments
• US Dept of Transp., Federal Highway Admin
• Nevada Dept of Transportation
• Nevada Office of Traffic Safety
• Regional Transp Commission of So. Nevada
• Clark County, Nevada
• City of Las Vegas
• UNLV TRC: students, staff
33
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