2. Drift-Off Crashes and the RUMBLE STRIPS that prevent them Dave Morena FHWA Michigan Division Sep 20, 2007

3. What is a drift-off crash?

4.  Driver ASLEEP, DROWSY  Driver DISTRACTED Drift-off crashes are Run-off-road crashes where:

5. Drift-off crashes are NOT:  swerve to avoid another vehicle  hydroplane  swerve to avoid debris  tire blowout  trailer sway

6. What do we know about drift-off crashes?

7. 1887 crashes 1996 - 2001 2002 study Drift-off crashes Michigan freeways

8.  Driver ASLEEP, DROWSY  Driver DISTRACTED (As specified on 1043 reports) - 82% - 18% Drift-off crashes are:

9. ASLEEP / DISTRACTED vs. AVOID VEHICLE or OBJECT Severity Quiz: 3 times as severe

10. ASLEEP / DISTRACTED vs. HYDROPLANE ?? Severity Quiz: 5 times as severe

11. Michigan Freeway Crashes - Severity 1996 - 2001 34,000 crashes/yr Multiple Vehicle mainline Run-Off-Road On-Road (deer) Single Vehicle 6.1 % KA 2. 9 % KA 0.4 % KA K = fatality A = incapacitating injury B = other injury C = possible injury O = property damage only

12. Michigan Freeway Crashes - Severity 1996 - 2001 34,000 crashes/yr mainline Run-Off-Road DROWSY & DISTRACTED ice, snow on road 2.9% KA wet road 3.4% KA avoid veh, enter, exit, change lanes, passing 6.1% KA Vehicle defect 5.8% KA 17 % KA Multiple Vehicle 2. 9 % KA

13. CRASH SEVERITY - % KA

14. Drift-off crash PROFILE Michigan freeway

15. ALL DRIFT-OFF 48 % K & A crashes 53 % Vehicles drift off which side of road?

16. 0% 1% 2% 3% 4% 5% 6% 7% 1357911131517192123 Time of Day Percent of Crashes Avg = 4.2% Drift off Crashes by Time of Day Dark - 55% Light - 45% time of day

17. 17.8 20.3 11.4 12.2 11.5 13.5 13.2 0 5 10 15 20 25 SunMonTuesWedThurFriSat Day Of Week Percent of Accidents Drift off Crashes by Day of Week Avg = 14. 3 %

18. Drift-off Vehicles by Gender of Driver Males account for: 59% of all Michigan crashes, 71% of fatalities Female Male 69%

19. Drift-off Vehicles – Driver Age 23% age 16-21

20. Drift-off Vehicles – Driver Age 19% age 16-21 All Michigan crashes 23% age 16-21 Drift off crashes

21. Truck Involvement Trucks accounted for 11 % of daily vehicle miles parked vehicles hit 10% drift-off vehicle 4%

22. Driver had been drinking in 21% of all drift-off crashes Alcohol Involvement

23.  parked vehicle  trees  signpost, light pole  guardrail, bridge rail  hit opposing vehicle  side slope, ditch What can happen to a drift-off vehicle?  recover (no crash) ??? 5 % 14 % 6 % 20 % 1 % 45 %

24. Once a wheel drops off paved shoulder, drivers have difficulty controlling vehicle: - 32 %  over-correct steering  rollover In 1794 crashes: - 45 %

25. Crash FREQUENCY: less than one crash / mile / year

26. Crash RATE: No rumble strips Drivers less likely to drift off on high-volume road

27. From crash data, problem areas: early morning hours low volume roads curves young driver

28. $750 / mile / shoulder A MACHINE TO CUT RUMBLE STRIPS: 7” x 16” x ½”

29. Effect of milled shoulder rumble strips on freeway DRIFT-OFF crashes: 100 60 7.2 17 40 % reduction – total crashes 58 % reduction – KA 17 % KA 12 % KA

30. Concrete intermittent Rumbles Should we install milled rumbles over concrete intermittent?

31. Concrete intermittent Rumbles Yes – provide continuous alert

32. Should we install milled rumbles over rolled? Rolled-in Rumble Strips

33. Yes – Milled rumbles provide vibration

34. ROLLED MILLED

35. How do these rumbles affect large-tired vehicles?

36. Bus/truck rumble demonstration Feb 17, 2000 - Lansing, MI

37. Answer: MILLED - vibrates steering wheel, some noise ROLLED - slight noise, drowned out by cab noise CONCRETE INTERMITTENT - drivers unaware

38. Dave Morena FHWA Michigan Division 517-702-1836 David.Morena@fhwa.dot.gov Questions & Comments