Rumble strips

Rumble strips (also known as audio tactile profiled markings) are a road safety feature that alert drivers to potential danger by causing a tactile vibration and audible rumbling, transmitted through the wheels into the car body. A series of rumble strips is usually either applied in the direction of travel along an edge- or centerline to alert drivers when they drift from their lane, or across the direction of travel to warn drivers of a nearby danger-spot."The hidden persuaders" - "Contractor" magazine, Vol 30 No 9, October 2007]

Rumble strips are usually made by scalloping a section out of the roadway in a regular pattern, although they can also be created by adding thermoplastics or cold-applied plastic round or rectangular bumps. Rectangular strips often have a reflector built into the edge. Round raised rumble devices are sometimes called Botts' dots. [ [http://www.dot.ca.gov/hq/paffairs/faq/faq63.htm Bumps between lanes] ] The raised type of rumble strip is common in southern climates, but impractical in northern climates due to the complication of snow removal.

History

Rumble strips were first implemented on the Garden State Parkway in New Jersey in 1952. Also known as "singing shoulders", they provided an alert system to prevent drivers from straying off the roadway. [cite web|url=http://www.nycroads.com/roads/garden-state/|title=Garden State Parkway|accessdate=2007-07-09] Rumble strips have also been used to prevent accidents caused by tired drivers straying out of their lane. [ [http://pdf.textfiles.com/academics/shoulderdrift.pdf Shoulder Rumble Stripps: A Method To Alert "Drifting" Drivers] - Wood, Neal E., Pennsylvania Turnpike Commission, January 1994]

Rumble strips have proven highly effective. New Zealand used rumble strips in small applications since the late 1980s, and started a larger program in 2004. Research in the country indicated that lane delineation with rumble strips reduced crashes by an average of 27% over all crash types and studies, with types of crashes such as "run off road" being reduced by up to 80% in some studies. Centre-line rumble strips showed similar effects.

The effects remained even after road users had gotten used to the novelty of the feature, while other road safety measures (when studied at specific installations) often showed declining effectiveness over time. Cost-benefit analysis showed that even on relatively low-volume roads, the costs of applying the markings were quickly exceeded several-fold by the economic benefits of improved road safety (as counted by the reduction of accident rates weighted against the average social costs of a crash).

Most California highways use ceramic or plastic Botts' dots in the area of the white and yellow dotted lines to serve as a rumble strip. [ [http://www.dot.ca.gov/hq/paffairs/faq/faq63.htm Bumps between lanes] ]

ee also

*Road surface marking
*Road traffic control

References