Rumble strips take a number of different forms, and can be produced by cutting grooves within the pavement surface, or by adding plastic bumps (or ribs) to the road.
Transverse rumble strips (also referred to as bar markings) are placed across the traffic lane to alert motorists to hazards ahead (such as bends, intersections or areas of pedestrian activity). They are most effective where drivers have been travelling at sustained high speed for long periods.
Longitudinal rumble strips (also referred to as raised profile edge lines or audio-tactile edge lines) can be used to delineate the edge of a road where driver fatigue is known to cause crashes. As well as providing visual delineation, longitudinal rumble strips can also be heard and felt by drivers and riders.
When a tyre runs over the rumble strips a noise and vibration is produced. This tells a sleepy or distracted driver that their vehicle is starting to leave the road.
Centreline rumble strips and flexi-posts. Longitudinal rumble strips can also be used in the centre of the road. When combined with painted centrelines, rumble strips help prevent head-on crashes and run-off-road crashes resulting from vehicles crossing into the opposing lane. Flexible posts (or flexi-posts) can also be used in the centre of the road to separate opposing flows and are an effective treatment in discouraging overtaking manoeuvres, reducing the likelihood of head-on crashes.
- Reduced run-off-road and head-on crashes.
- Reduced collision at diverge gores
- Improved visibility of edge lines or centre lines during wet weather.
- Potential for reduced maintenance of road shoulder.
- Advanced warning to hazards.
- Where used on high-speed roads, transverse bar markings have been shown to reduce speeds on approaches to intersections such as roundabouts.