Two-Way Left Turn Lane (TWLTL) Restrictions DEFINITION AND DESCRIPTION Two-way left-turn lanes (TWLTLs) enhance safety and traffic flow at locations with moderate traffic volumes and moderate to high access point densities. They are typically installed when access...
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...
Curb Extensions Image Source: Google Earth, Paducah DEFINITION AND DESCRIPTION A curb extension is a horizontal extension of the sidewalk into the street that results in a narrower roadway section. They may be placed at intersection corners or mid-block. A curb...
Protected Intersection Image Source: FHWA DEFINITION AND DESCRIPTION Protected intersections use a setback or offset design to minimize conflict points and improve visibility between drivers, pedestrians, and/or bicyclists. Features of protected intersections include...
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...
