David RushWork Zone Safety Program Manager

Traffic Engineering Division, Central Office

Young-Jun KweonSenior Research Scientist

Virginia Transportation Research Council

VASITE Annual

Meeting

June 30 2016

Looking into Virginia’s Work

Zone Safety 2011-2015

OUTLINE

PART I Work Zone

PART II Work Zone

2

by David

by Young-Jun

Crash Statistics

Safety Measures

PART I

Work Zone

Crash Statistics

3

5-Year Crashes

4

Annual Counts

3,445 3,464 3,404

4,071

2,622

0

1,000

2,000

3,000

4,000

2011 2012 2013 2014 2015

Yea

rly

Cra

shes

Year

Increased risk

for workers and

motorists.

Crash Severity

5

Fatal Injury

(K)

58

0%

Incapacitating

(A)

822

5%

Non-Incapacitating

(B)

2,777

16%

Possible Injury

(C)

1,998

12%

No Injury

(O)

11,351

67%

5-Year Crashes:

▪ 17,006 WZ crashes

▪ 66 WZ fatalities

6

Number of Vehicles

5-Year Crashes

1 Vehicle

2,428

14%

2 Vehicles

11,466

68%

3 Vehicles

2,452

14%4 Vehicles

523

3%

5+ Vehicles

137

1%

5-Year Crashes

Collision Type

7

Still the #1 crash in WZs!

Rear End

9,329

55%

Angle

2,415

14%

Fixed Object,

Off Road

2,218

13%

Sideswipe,

Same Direction

182

1%

Others

2,862

17%

5-Year Crashes

Light Condition

8

Daylight

11,690

69%

Darkness,

Road Lighted

2,647

16%

Darkness,

Road Not

Lighted

1,981

12%

Others

688

4%

5-Year Crashes

Unknown includes non-VDOT roads or missing information.

Functional Class

9

Rural Interstates

869

5%

Rural Routes

833

5%

Urban Interstates

8,435

50%

Urban Routes

5,036

30%

Unknown

1,833

11%

5-Year Crashes

District

10

Bristol

467

3%

Salem

759

4%

Lynchburg

289

2% Richmond

1,870

11% Hampton

Roads

2,237

13%

Fredericks-

burg

1,085

6%

Culpeper

392

2%Staunton

442

3%

Northern

Virginia

9,465

56%

Percentage in 5-Year Crashes

DistrictBy Light Condition

11

Bristol Salem Lynchburg RichmondHampton

Roads

Fredericks-

burgCulpeper Staunton

Northern

Virginia

Daylight 88% 75% 79% 67% 59% 72% 78% 77% 68%

Darkness, Road Lighted 3% 6% 9% 8% 31% 3% 4% 3% 18%

Darkness, Road Not Lighted 6% 15% 9% 21% 6% 22% 13% 16% 10%

Others 4% 4% 3% 4% 4% 3% 5% 5% 4%

0%

20%

40%

60%

80%

100%

Colu

mn

Per

cen

t

District

Passenger Car

19,326

54%

SUV

6,335

18%

Pickup Truck

3,691

10%

Truck

3,129

9%

Van

2,118

6%

Others

661

2%

Motorcycle

302

1%

Vehicles in 5-Year Crashes

Vehicle Type

12

PART II

Work Zone

Safety Measures

13

by Young-Jun

VDOT’s Metrics

VDOT had been using two metrics to measure work zone

safety performance of Virginia

14

Annual Persons Killed and Serious Injury in Work Zones

0

2

4

6

8

10

12

14

16

18

20

2004 2005 2006 2007 2008

Year

Pers

on

s K

ille

d

0

50

100

150

200

250

300

350

400

450

Pers

on

s S

eri

ou

sly

In

juri

ed

Deaths Serious Injuries

Issues with the Metrics

Count of Persons. It is affected by:

▪ Number of persons in a vehicle

▪ Number of vehicles in a crash

No exposure accounted. Examples of exposures are:

▪ Number of work zones

▪ Length of work zones

▪ Number of vehicles passing through work zones

15

Count Measures

▪ Directly measure traffic safety consequences

▪ (e.g.) Numbers of fatalities & fatal crashes in a year

Exposure Measures

▪ Capture level of an exposure to traffic crash risk

▪ (e.g.) Number of work zones in a year

Rate Measures

▪ Reflect both count and exposure measures

▪ (e.g.) Fatal crashes per 1,000 work zones in a year

3 Types of Measures

2015✓ 10 work zone crashes✓ 5 work zones✓ Each work zone 10 miles long✓ Each work zone lasted 1 month

2014✓ 10 work zone crashes✓ 10 work zones✓ Each work zone 1 mile long✓ Each work zone lasted 1 year

We need exposure measures!!

16

Research Project

Title: Work Zone Safety Performance Measures for

Virginia

Team: Young-Jun Kweon, Mike Fontaine, In-Kye Lim

Review Panel: David Rush, Mark Cole, Tim Rawls,

Forester Wright

17

4 Performance Measures

① total crashes, ② fatal & injury crashes

③ crashes per work zone-hour-mile

④ fatal & injury crashes per work zone-hour-mile

8 Summary Measures

① fatalities and injuries

② crashes per work zone, ③ crashes per work zone-hour, ④ fatal &

injury crashes per work zone,

⑤ work zones, ⑥ work zone-hours, ⑦ work zone-miles, and ⑧ work

zone-hour-miles

Virginia’s WZ Safety Measures

18

Performance MeasureAll Work Zone Crashes

19

Summary MeasureWork Zones

20

Summary MeasureWork Zone-Hours

21

Summary MeasureWork Zone-Miles

22

Summary MeasureWork Zone-Hour-Miles

23

Performance MeasureAll WZ Crashes

Per Million Work Zone-Hour-Miles

24

Cautions

Technical definition of a work zone crash

▪ Previous publications used road defect information whereas the

current one uses work zone status information.

Issues with rate measures

▪ Valid as long as “linearity condition” is met.

▪ Omitted influential factors (e.g., traffic volume and work zone type)

25

26

Question?Thank You!