Variable Speed Limit Goes Live on Part of I-495 in Va.

Effective Monday, speed limits on part of Interstate 495 in NorthernVirginia began changing along with traffic conditions, the AssociatedPress reported.

Initially, the variable speed limit will be in effect only at night, when certain lanes of I-495 near the Woodrow Wilson Bridge will be closed for roadwork, AP said.

By lowering the speed limit as congestion increases, VDOT hopes to prevent rear-end collisions that can occur as a result of the “funnel effect” that is created when faster-moving traffic approaching the Wilson Bridge is forced to slow down and exit lanes that are closed for construction, AP said.

Speed limits along the affected portion of I-495 will range from 35 mph to 55 mph, de-pending on congestion, AP said.

VDOT operators will use traffic cameras and sensors to monitor congestion and adjust speed limits accordingly, AP said.