Numerous rumble strip designs have been implemented and evaluated nationally. Data gathered by different US States, reviewing the various standards, specifications, and key modifications to the standard Rumble Strips are shown below.
Transverse Width
With the exception of one State, all US States identified use of 300mm as a minimum transverse Rumble Strip width for verge edge treatments.
Depth
Considerable research work has been conducted in the US, with cut depth varying between 10 and 16mm.There exists, the flexibility to vary the depth of cut of Rumble Strips according to the class of vehicle using the road, e.g. deeper cut on heavy vehicle routes. However, given the increased effectiveness of milled rumble strips over pavement marked audio tactile, it makes sense to adopt a standard in Australia of 10 – 12mm.
Skip Pattern
Originally Rumble Strips were placed continuously on the shoulder. More recently at least ten US States have implemented a skip pattern, such as ten meters with and ten meters without Rumble Strips. This design is intended to allow bicyclists to cross from one side of the strip to the other without much difficulty while still maintaining the ability to alert errant drivers.
Placement
The two main theories are to place the Rumble Strips close to the edgeline or close to the edge of shoulder. Most US States are following the practice of installing the SRS near the edgeline but some States place SRS near the edge of shoulder.
SRS placed near the edgeline allow the remainder of the shoulder to be utilised by other users, such as bicyclists or pedestrians. Furthermore, it also places a warning device between errant motor vehicles and bicyclists.
