Traffic Control Devices and Measures for Deterring Wrong-Way Movements

Thursday, November 15, 20182:00-3:30 PM ET

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Purpose

Discuss NCHRP Research Report 881: Traffic Control Devices and Measures for Deterring Wrong-Way Movements.

Learning Objectives

At the end of this webinar, you will be able to:

• Identify characteristics of wrong-way driving crashes on divided highways

• Describe methods for mitigating wrong-way driving on divided highways

NCHRP Research Report 881: Traffic Control Devices and Measures for Deterring Wrong-Way Movements

NCHRP Project 03-117

NCHRP is a State-Driven Program

– Suggest research of national interest

– Serve on oversight panels that guide the research.

• Administered by TRB in cooperation with the Federal Highway Administration.

• Sponsored by individual state DOTs who

Practical, ready-to-use results• Applied research aimed at

state DOT practitioners• Often become AASHTO

standards, specifications, guides, syntheses

• Can be applied in planning, design, construction, operations, maintenance, safety, environment

Traffic Control Devices and Measures for DeterringWrong-Way MovementsMelisa D. Finley, P.E.Texas A&M Transportation Institute (TTI)

November 15, 2018

Acknowledgements

Steve Venglar, P.E.TTI

Gene Hawkins Ph.D., P.E.Texas A&M University

Haitham Al-Deek, Ph.D., P.E.University of Central Florida

Raul Avelar, Ph.D.TTI

NCHRP Project 03-117 Objectives• Primary

• Examine characteristics of wrong-way crashes on divided highways• Determine the impact of median width and select traffic control devices on

their occurrence• Secondary

• Determine effectiveness of emerging countermeasures implemented at freeway exit ramps

Divided Highway Definition

Median Width Definition

Median Width

Median Width Threshold

DO NOT ENTER and WRONG WAY signs• Figure 2B-12 only for median widths ≥ 30 ft and does not indicate

required versus optional signs• Ambiguity surrounding

side of road forDO NOT ENTER andWRONG WAY signs

Divided Highway Multistate Dataset• High-speed (≥ 50 mph)• Developed procedure for identifying most likely wrong-way entry points

Texas(2012-2014)

Florida(2010-2013)

California(2008-2011) Total

Wrong-Way Crashes- Urban- Rural

18366

117

16010159

662838

409195214

Crash Corridors- Urban- Rural

16857

111

1429448

482127

358172186

Control Corridors- Urban- Rural

1225765

1379344

49427

308157151

Percent of Wrong-Way Crashesby Crash Severity

60%57%

32%

54%

39%42%

68%

45%

1% 1% 0% 1%0%

10%

20%

30%

40%

50%

60%

70%

80%

Texas(n=183) Florida (n=160) California (n=66) Total (n=409)

KAB CO Unknown

KAB = Killed, Incapacitating Injury, and Non-Incapacitating Injury; CO = Possible Injury and Not Injured

Percent of Wrong-Way Crashesby Lighting Condition

32% 30%

54%

35%

3% 2%

8%3%

65%68%

38%

62%

0%

10%

20%

30%

40%

50%

60%

70%

80%

Texas (n=183) Florida (n=160) California (n=66) Total (n=409)

Daylight Dawn/Dusk Night

Intersection Type at Most LikelyWrong-Way Entry Points

Intersection Type Texas(n=183)

Florida(n=160)

California(n=66)

Total(N=409)

Ramp 22 (12%) 3 (2%) 9 (13%) 34 (8%)Crossed median 2 (1%) 0 (0%) 0 (0%) 2 (<1%)Median opening only 14 (8%) 11 (7%) 3 (5%) 28 (7%)Private or business driveway- With median opening- Without median opening

21 (11%)10 (5%)11 (6%)

1 (<1%)0 (0%)

1 (<1%)

5 (8%)2 (3%)3 (5%)

27 (7%)12 (3%)15 (4%)

Three-leg intersection- With median opening- Without median opening

73 (40%)64 (35%)

9 (5%)

104 (65%)66 (41%)38 (24%)

22 (33%)16 (24%)

6 (9%)

199 (49%)146 (36%)53 (13%)

Four-leg intersection with median opening 51 (28%) 41 (26%) 27 (41%) 119 (29%)

Divided Highway Wrong-Way Entriesin Texas

90%

10% 63% entered via at-grade intersections

Median Width at Wrong-Way Entry Points with Median Openings

n=277

Type of Control in Median Openingat Wrong-Way Entry Points

n=27718% 82%

40%

43%

72%

12%

17%

Wrong-Way Driver Characteristics

60%

35%

N=315. Totals do not add to 100% due to blank entries (i.e., no gender or age reported).

6%

22%

15%14%

14%

24%<2121-2930-3940-4950-59>=60

Wrong-Way Driver Characteristics, cont.

N=315. Totals do not add to 100% due to blank entries (i.e., no age reported).

32%

24% 19%

28%

39% 40%

68%

76% 81%

72%

61% 60%

<21 21-29 30-39 40-49 50-59 >=60

Day Night

Wrong-Way Driver Characteristics, cont.• 39% alcohol entry blank• 40% tested negative for alcohol• 21% tested positive for alcohol

• More than 90% BAC level ≥ 0.08 g/dL (legal limit)• Almost 70% had a BAC level ≥ 0.16 g/dL (twice the legal limit)• Almost 25% had a BAC level ≥ 0.24 g/dL (three times the legal limit)

N=315.

Overview of Statistical Analyses• High-speed, four lane divided highways with median openings at

intersecting roadways (median width ≤ 120 ft)• Defined response variable as the probability of wrong-way crashes• Logistic regression used to model relationships with potential

explanatory variables as changes in the odds of a wrong-way crash occurring

• Odds ratio = 1; no change• Odds ratio < 1; reduction in odds• Odds ratio > 1; increase in odds

Modeling Process• Modeling stages

• Major design/operation variables• Stepwise model selection procedure for traffic control device variables• Testing of all models for variable interactions and model fit

• 4 safety models developed• Rural – all wrong-way crashes• Rural – nighttime wrong-way crashes• Urban – all wrong-way crashes• Urban – nighttime wrong-way crashes

Traffic Control Devices

Variables Related to Reduction in Odds of Wrong-Way CrashesDO NOT ENTER and WRONG WAY signs on outside ofwrong-way maneuver

Variables Related to Reduction in Odds of Wrong-Way Crashes, cont.Required ONE WAY signs

Variables Related to Reduction in Odds of Wrong-Way Crashes, cont.Wrong-way arrow markings on divided highway through lanes

Variables Related to Reduction in Odds of Wrong-Way Crashes, cont.• Centerline in median opening• Use of stop or yield lines in

median opening when interiorcontrol provided

Crash Correlation to Median WidthDependent upon presence of control in median opening

Control in Median Opening Change in Wrong-Way Crash Odds

or None

NoneIncreased by a multiplicative factor

for every additional 10 ft of median width

Effect of Median Width Without Control in Median Opening and per-site Variability

Summary of Findings• Median width and number of intersections more complex than a

single number• Greater use of ONE WAY signs (above those that are required) does

not appear to deter wrong-way movements• Treatments that appear to deter wrong-way movements

• DO NOT ENTER and WRONG WAY signs on outside of wrong-way turn• Required ONE WAY signs• Wrong-way arrow markings for through lanes• Centerline in median opening• Stop or yield lines in median opening when interior control used

Overview of Recommended Changes to MUTCD• Determination of single or separate intersections

• Remove 30-ft median width threshold• Base on opposing left-turn paths and storage

• Revised median width definition• Revised Section 2A.23 Median Opening Treatments for Divided

Highways with Wide Medians

Overview of Recommended Changes to MUTCD, cont.• DO NOT ENTER and WRONG WAY signs

• Changes to text and figures to clarify appropriate side of road for first and second signs

• Allow use of red LEDs• New section for wrong-way traffic control at divided highway crossings

• Language consolidated from other sections• Similar to Section 2B.41 for interchange ramps

Overview of Recommended Changes to MUTCD, cont.• Section 2B.32 KEEP RIGHT and KEEP LEFT signs• Section 2B.40 ONE WAY signs• Section 2B.41 Wrong-Way Traffic Control at Interchange Ramps• Section 2B.42 Divided Highway Crossing Signs• Section 3B.20 Pavement Word, Symbol, and Arrow Markings

Melisa D. Finley, P.E.Texas A&M Transportation Institute979-845-7596m-finley@tti.tamu.edu

Report available at http://apps.trb.org/cmsfeed/TRBNetProjectDisplay.asp?ProjectID=3856

Today’s Speakers• Tom Heydel, Wisconsin Department of

Transportation, Tom.Heydel@dot.wi.gov• Melisa Finley, Texas A&M Transportation

Institute, m-finley@tti.tamu.edu

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