The safety of freeways and other limited access facilities on the State highway system is to be enhanced by the installation of shoulder warning devices in the form of rumble strips.
Projects on limited access facilities shall include the construction of ground-in rumble strips. Several types of applications have been tested. The ground-in strips provide the desired warning to the driver and consistency in application has been possible using this construction process.
These ground-in strips are installed using two patterns. The skip array is the standard array. These are used on both inside and outside shoulders on divided highway sections.
The continuous array shall be constructed in advance of bridge ends for a distance of 300 meters or back to the gore recovery area for mainline interchange bridges. Other areas may be specified in plans.
Methods and types of application other than described above and in Roadway and Traffic Design Standards, Index 518 shall not be used unless concurred in by the State Roadway Design Engineer. Approval will be considered only with sufficient documented justification for deviation from the standard.
Roadway and Traffic Design Standards, Index 518 has been prepared to provide all needed details. This index also gives standards for raised rumble strips for use at structures where the bridge shoulder width is less than the width of the useable shoulder on the approach roadway. Notes for locations of raised rumble strip applications are also included on the index.