Evaluation of Advisory Exit and Ramp Speed Signs

• October 8th, 2024

A past research effort initiated by the Federal Highway Administration (FHWA) found that the combined workload of guidance (i.e., selection of
the vehicle path) and control (i.e., physical operation of the vehicle) in the vicinity of interchanges creates a particularly challenging environment for
motorists (Katz et al. 2018). At interchange ramp locations, drivers use cues from the roadway geometry, pavement markings, and signs to determine the
appropriate path and speed at these locations. Changes in both horizontal and vertical alignment on interchange ramps can make these locations
particularly challenging. More crashes occur at freeway entrance and exit ramps than on other segments of interstate highways, and run-off-road
crashes (for which speed is often a factor) are the most common types of crashes on exit ramps (McCartt, Northrup, and Retting 2004).

Read the full study here.