Raised Intersections Image Source: NACTO DEFINITION AND DESCRIPTION A raised intersection functions like a speed table but extends across the full width of the intersection.. Ramps are installed on each approach, and the intersection elevation is flush with the...
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...
Speed Reduction Markings Image Source: Google Earth DEFINITION AND DESCRIPTION Speed Reduction Markings, or optical speed bars (OSBs), are white transverse pavement markings placed on both sides of a lane perpendicular to the centerline, edge line, or lane line with...
Speed Feedback and Changeable Message Signs DEFINITION AND DESCRIPTION Dynamic speed feedback signs contain devices that measure the speed of an approaching vehicle and displays the speed to the vehicle operator. They are used to provide warning to drivers of their...
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...
Roadway Narrowing: Pavement Markings Image Source: FHWA DEFINITION AND DESCRIPTION Roadway narrowing is often done as part of resurfacing or roadway improvement projects. It may include repurposing additional paved space with markings or physically removing unused...
