Four projects were built over two construction seasons using special devices attached to the paving machine that produced a 30º slope on the outside pavement edge instead of the near vertical drop-off common with conventional paving equipment. This pavement edge treatment allows vehicles that leave the roadway a gentler slope to navigate when remounting the pavement.
The projects used four types of devices; (1) the TransTech Shoulder Wedge MakerTM, (2) the Advant-EdgeTM, (3) the Carlson Safety Edge End Gate, and (4) a contractor built device. All of the devices were able to produce a finished pavement slope that was close to the 30º angle recommended by the Federal Highway Administration (FHWA).
The projects will be monitored for five years to measure the functional performance of the edge treatment and possible reductions in collisions caused by drivers trying to re-enter the roadway after losing control and running off the road.
Washington (State). Dept. of Transportation. Materials Laboratory
Dropoffs (Pavements), Road construction, Pavement design, Geometric design, Road shoulders, Paving, Pavers, Clear zones, Highway safety.