Superelevation Improvement Image Source: Google Earth DEFINITION AND DESCRIPTION Superelevation promotes motorist comfort as they accelerate a vehicle through a curve. Superelevation may be inadequate due to long-term deterioration from settlement or pavement...
Slope Flattening DEFINITION AND DESCRIPTION Slope flattening reduces the steepness of the roadside and median slopes so that errant motorists are more likely to keep their vehicles stable, regain control, and avoid obstacles. Slopes of 4H:1V or flatter are recoverable...
Sequential Dynamic Chevron Warning System Image Source: Iowa State University Center for Transportation Research and Education DEFINITION AND DESCRIPTION A sequential dynamic curve warning system (SDCWS) consists of a series of solar-powered LED chevron signs...
Median Barriers on Undivided Roadways Image Source: FHWA DEFINITION AND DESCRIPTION Median barriers separate opposing traffic and reduce head-on crashes. In the U.S., median barriers on undivided roadways are uncommon; however, other countries (e.g., Sweden) have used...
Increase Use of Roadside Barriers and End Terminals DEFINITION AND DESCRIPTION When it is not feasible to remove or relocate a roadside obstacle, it may be shielded by a longitudinal traffic barrier or crash cushion. A roadside barrier redirects or contains errant...
Supplemental In-Lane Pavement Markings Image Source: Julian, F. Horizontal Signing, A Proven Low-Cost Horizontal Curve Safety Countermeasure.2024 TRB International Roadside Safety Conference presentation. DEFINITION AND DESCRIPTION Regulatory, warning, or guidance...
