overview of systemic approach to safety · pedestrian/bicycle 87 22% 60 15% 84 20% 100 19% ......

NACE/FHWA Local Road Safety Plan Pilot

December 2018 Workshop 1

Overview of

Systemic Approach to Safety

1

Example: Fatal Crash Locations

Source: NHTSA (https://cdan.nhtsa/gov/stsi.htm#)

2

201420152016



Crash Type2012 2013 2014 2015

# % # % # % # %

Roadway Departure 243 60% 247 62% 252 59% 290 56%

Pedestrian/Bicycle 87 22% 60 15% 84 20% 100 19%

Intersection 98 24% 110 27% 131 31% 160 31%

TOTAL 403 401 429 516

Example: Major Fatal Crash Types in Washington by FHWA Focus Area

Source: FHWA ‐ https://rspcb.safety.fhwa.dot.gov/Dashboard/Default.aspx

3

Systemic Safety Project Selection

1. Systemic Process

2. Balance Funds

3. Evaluate Effectiveness

https://safety.fhwa.dot.gov/systemic/fhwasa13019/sspst.pdf

4

FHWA’s Systemic Safety Tool



Element 1

Systemic Safety Planning Process

5


Step 1

Step 2

Step 3

Step 4

6




• Step 1: Identify…–Focus Crash Types

–Focus Facility Types

–Risk Factors

7

What we mean by “focus crash type”

Crash type representing greatest number of severe crashes across roadway system…

… provides greatest potential to reduce fatalities and severe injuries

• Road Departure

• Intersection

• Pedestrian

• Speeding

8



Task 1: Select Focus Crash Types

• Systemwide analysis

• Strategic Safety Plans

• Regional and jurisdictional analyses

–May differ from statewide needs

9https://www.maxpixel.net/Accident‐Broken‐Auto‐Damage‐Vehicle‐Total‐Damage‐1409006

Task 1: Select Focus Crash Types

Fatal and Severe Injury Crashes (2007‐2011)Percent by Jurisdiction

Emphasis AreaStatewide114,592 mi

State15,486 mi

County19,938 mi

City, Town, Village76,735 mi

Total Fatal/Serious Injury 100% 63,443 31% 19,819 10% 6,572 45% 28,597

Pedestrian 19% 11,786 9% 1,860 6% 421 28% 8,122

Bicycle 5% 3,390 3% 518 3% 187 8% 2,414

Heavy Vehicle 5% 3,123 6% 1,266 4% 234 4% 1,051

Road Departure 26% 16,668 30% 5,985 44% 2,892 18% 5,128

Intersection 41% 25,791 25% 5,033 30% 1,957 64% 18,270

Head‐on and Sideswipe 5% 3,071 7% 1,439 7% 490 3% 887

10



What we mean by “focus facility”

Facility type where focus crash type most frequently occurs

• Rural, Two‐Lane Highways

• Urban, Signalized Intersections

• Horizontal Curves

• Rural, Thru‐STOP Intersections

11

Task 2: Select Focus Facilities

12

5 years, Severe Roadway Departure

State System4,400 crashes

Urban1,900 crashes

Undivided1,102

Divided798

2 Lanes897

3 Lanes28

4 Lanes170

5‐6 Lanes7

< = 25 mph2

30‐35 mph195

40‐50 mph363

55+ mph336

Unknown1

< = 25 mph7

Rural2,512 crashes

Undivided2,165

Divided375

1 Lane1

2 Lanes2,090

3 Lanes35

4 Lanes39

30‐35 mph163

40‐50 mph281

55+ mph1,637

Unknown2

Rural2,500 crashes

Urban1,900 crashes



What we mean by “risk factor”

Characteristics associated with locations where targeted crash types occur

• Volume

• Alignment

• Intersection Control

• Presence of Shoulders

13

http://www.creative‐commons‐images.com/highway‐signs/r/risk.html

Potential Risk Factors

Roadway features:

• Lane width

• Shoulder width / type

• Median width / type

• Horizontal curvature

• Pavement condition / friction

• Roadside features– Sideslope design

– Clear zone

• Driveway density

14




Intersection features:

• Traffic control

• Turn lanes

• Skew angle

• Sight distance

• Presence of horizontal curve

• Railroad crossing

• Type of development (e.g., commercial)

15


Pedestrian‐related features:

• Traffic control

• Sidewalk presence

• Crosswalk presence

• Crossing distance

• Adjacent land uses

• Lighting

16




Other general features:

• Traffic volume

• Speed

– Posted, operating

17Source: Seattle DOT

Descriptive Statistics Analysis

18

23% 25%

8%

44%

85%

38%

20%

5%12%

88%

0%

10%

20%

30%

40%

50%

60%

70%

80%

90%

100%

Narrow Clearzone Passing Lane Street Lighting Paved Shoulder Narrow Shoulder (< 3 feet)

Percent

Presence of Potential Risk Factor

Potential Risk Factors for Rural Lane Departure Crashes

Percent of System With Potential Risk Factor

Percent of Severe Lane Departure Crashes Where Potential Risk Factor is Present



Descriptive Statistics Analysis

19

0%

5%

10%

15%

20%

25%

30%

35%

40%

45%

50%

Percent

Vehicles Per Day

Daily Traffic Volume

Percent of Severe Run Off Road Crashes Percent of Severe Across Centerline Crashes

Percent of Miles

Data Sources

• Crash data– Law enforcement– State or local database– FARS

• Roadway data– State or local database– Video logs– Online aerial imagery– Windshield surveys

• Exposure data (AADT)– State or local database– Traffic counts

20

Where do these data come from in your jurisdiction?



Reasons for Systemic

21

Systemic Approach to SafetyUsing Risk to Drive Action

22

Source: https://safety.fhwa.dot.gov/systemic/



Tool Demo

23

24

Intersection

4 (17%)

Wet Dry Wet Dry Wet Dry Wet Dry

0 (0%) 1 (100%) 1 (14%) 6 (86%) 2 (20%) 8 (80%) 0 (0%) 2 (100%)

Non‐Intersection

20 (83%)

County Roads

24 Fatal and Serious Injury, Roadway Departure Crashes

2 (16%)

Day Night

1 (12%) 7 (88%)

Day

10 (84%)

Curve Tangent

12 (60%)8 (40%)

Night



25

Intersection4 (17%)

Wet Dry Wet Dry Wet Dry Wet Dry8 (80%) 2 (20%) 0 (0%) 2 (100%) 0 (0%) 1 (100%) 1 (14%) 6 (86%)

12 (60%) 8 (40%)

County Roads

24 Fatal and Serious Injury, Roadway Departure Crashes

Non‐Intersection20 (83%)

Curve Tangent

Day Night Day Night10 (84%) 2 (16%) 1 (12%) 7 (88%)

overview of systemic approach to safety · pedestrian/bicycle 87 22% 60 15% 84 20% 100 19% ......

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