What are the most common areas where 'rumble strips' are installed in pavement and what is their function?

Answer 1

Rumble strips are raised strips of concrete placed in wide sections across the roadway or highway, and one set of rumble strips are followed by more sets. Their common name comes from the deep rumble sound that is produced as the vehicle travels over the raised strips.

The most common areas to find (or hear!) rumble strips include:

• On steep down-slopes that approach a tunnel or bridge. Here, the strips alert drivers to be alert, slow down, and approach with caution.
• On grades coming into a Toll Booth area. Here, the strips act as a warning to slow down and often signs are also posted to "Check Brakes". These strips were introduced after truckers and motorists plowed into toll booths and act as a warning to be alert, slow down, and approach with caution, as well as to check brakes before approaching.
• On the down-slope of mountains, such as the Allegheny Mountains in Pennsylvania. Often mountains produce thick foggy areas, so rumble strips help alert drivers to down-grades and need for caution.
• Within areas of down-grades plus frequent curves, such as in mountainous areas. See above.
• Along the edges of shoulders on curving roadways, especially ones with drop offs or steep ravines. Here, rumble strips snap drivers awake and alert drivers that they have drifted onto the shoulder, allowing the driver time to correct their course and prevent an accident.
• At the beginning and throughout U-shaped ramps, or ramps with steep banking curves. Often, these ramps are two-way with a low cement barrier between the lanes. Many 18-wheelers can "jump" the barriers if the truck is traveling too fast for the curve. Here, rumble strips awaken sleepy drivers, bring attention to a dangerous condition, and remind drivers to slow their speeds dramatically.
• At exits to rest stops, especially when the rest stop includes a gas station and the distance from roadway to the pumps is a short distance. Drivers must slow down, thus preventing a vehicle from running into a pump and causing a fire / explosion.

If drivers attempt to continue at high speeds, the rumble strips being placed closely together in sets will vibrate and shake the vehicle strongly enough that almost all drivers WILL slow down to avoid the shaking.