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

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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

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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

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