R R UU M M B B L L EE S S TT R R II P P SSBy Gary Dirlam, Mn/DOT District 3 Traffic Engineer

Last year 657 people died on Minnesota Highways

Mn/DOT Lost one of it’s own to a Head-On Crash

Head On and Sideswipe - Fatal and A Injury CrashesStatewide All Two Lane Roads

0

50

100

150

200

250

300

350

1993 1994 1995 1996 1997 1998 1999 2000 2001 2002

Year

Number

A Injury

Fatal

Head On and Sideswipe - Fatal and A Injury CrashesTrunk Highway Two Lane Roads

0

20

40

60

80

100

120

140

1993 1994 1995 1996 1997 1998 1999 2000 2001 2002

Year

Number

A Injury

Fatal

PennDOT conducted rumble strip research on two lane rural road highways.

R O A D R E S E A R C H

PennDOT has adopted Centerline Rumble Strips as part of its 3R program estimating a

20% reduction in fatal crashes.

R O A D R E S E A R C H

• 82 % drift off road drivers were drowsy/asleep• 53% drift off road right/ 47% drift off road left• Micro-sleeps of 4-5 seconds, vehicle can

travel 300 feet• Micro-sleep—eyes stay open, brain not

processing information

Michigan Study

R O A D R E S E A R C H

• Multi-state review (7 states)

• 98 sites with 211 miles

Insurance Institute for Highway Safety

R O A D R E S E A R C H

• AADT range from 5,000 to 22,000

• Average ADT of 8,800 to 9,700 after

• Overall 14% reduction in all crashes

Insurance Institute for Highway Safety

R O A D R E S E A R C H

• 25% reduction in injury head-on and side-wipe crashes

• Only Minn. showed increase in opposing direction injury crashes

• Minn. increase was not statistically significant

Insurance Institute for Highway Safety

R O A D R E S E A R C H

• Maine is the only other state I know which has used the RS each side of Centerline

• Washington State and Oregon have included a widen center median to install the Rumble Strip

Design of Centerline Rumble Strips

R O A D R E S E A R C H

• Experimental application of centerline rumble strips– Milled-in a center median– In no passing zones

• Tactile vibration if driver encroaches centerline

• Installed 2 years ago

Oregon Solution

R O A D R E S E A R C H

• Next steps:– wait for one more year of data– develop regression models– apply comparison group and empirical-bayes

approach

• Data would indicate the rumble strips have been effective at reducing target crashes

Oregon: Conclusions after 2 years

R O A D R E S E A R C H

Design of Centerline Rumble Strips

• California, Pennsylvania,and Colorado have used the Rumble Strips across the Centerline

• Minnesota Metro has used Rumble Strips across Centerline as has Districts 6, 3 and 8 on Highway 23

R O A D R E S E A R C H

Design of Centerline Rumble Strips

• District 3 has used the separated Rumble Strips for the 8 miles installed on Highway 55 and 4 miles on Highway 169 in 2000

• District 3 has used the separated Rumble Strips for the 190 miles installed October 2003

R O A D R E S E A R C H

Where Installed?

R O A D R E S E A R C H

• Each section of the 190 miles of new rumble strip had one fatal crash in last 10 years

• Evaluate performance over this winter

• Plan for second CLRS project

Minnesota Research• Research driver interaction with

centerline rumble strips and design of centerline RL

• Research mid-lane rumble strip

• Mid-lane could replace centerline and shoulder rumble strip

R O A D R E S E A R C H

Rumble StripsRumble Strips in District 3in District 3

I N S T A L L A T I O N

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I N S T A L L A T I O N

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Sweeps up debrisI N S T A L L A T I O N

Challenge to Materials Engineers

• Safety problem is too great to ignore and/or accept 5 fatal crashes each year in District 3

• Materials Engineers’ challenge is to develop treatment for RS to preserve pavement life and life of pavement markings

T H E F U T U R E

Challenge to Materials Engineers

• District 3 recently installed shoulder RS on Highway 12 which were fog sealed

• Fog seal also fogged the epoxy edge line• District 4 masked over center line tape

with protective covering and removed covering after paver passed over

T H E F U T U R E

Challenge to Materials Engineers• Next day, fog seal of macro surface

covered up tape pavement markings—$2.12 /ft material investment covered (tape was 5 years old)

• So far I have not heard of any contractor paying for ruining pavement markings

T H E F U T U R E

Questions or Comments

Q&A

Building More. Building Faster. Moving Better.