Recently Completed: I-95 Northbound Variable Speed Limits

The Virginia Department of Transportation (VDOT) has installed variable speed limits to enhance safety in the I-95 northbound corridor between mile markers 115 and 130 in Caroline and Spotsylvania counties, and the City of Fredericksburg.

Crashes have occurred when northbound vehicles traveling at speed unexpectedly encounter stopped or slowing traffic flow due to congestion or lane closures for incidents and highway work zones.

New LED signs displaying variable speed limits between 35 mph and 65-70 mph are paired with dynamic message boards in this section of I-95 northbound. Drivers adjust their speed based on real-time information about delays and conditions on the road ahead. Gradually slowing traffic as it approaches congestion will help to reduce the risk of crashes, and stop-and-go travel conditions.

The variable speed limit signs are located every half-mile to one mile in the project corridor, with a total of 48 speed limit signs, installed in pairs.

The new signs were activated on June 22, 2022. 

Speed limits are reduced only when necessary. Vehicle detectors collect traffic speed and volume data, which is fed into a software program to recognize when traffic is approaching unstable conditions (for example, very high volume and fast speed) and assign incrementally lower speeds. Once traffic flow stabilizes, the posted speed limit returns to the maximum speed. 

Speed limits posted on VSL are enforceable just like regular speed limit signs. Enforcement authorities will have access to real-time changes in posted speed limits along the VSL corridor.

Variable speed limits were recommended for this section of I-95 northbound as part of the I-95 Corridor Improvement Plan. Based on the expected success of this deployment, VDOT anticipates implementation of VSL at additional locations throughout the Commonwealth.

Learn more: 

News Release: I-95 Northbound Variable Speed Limits to Begin

Commonwealth Transportation Board presentation, April 2021

Frequently Asked Questions (FAQ)

Video 

Commonwealth Transportation Board presentation, January 2022

Benefits 

• Seeks to reduce crashes 
• Increases vehicle throughput
• Fewer stop-and-go conditions 
• Informs travelers of conditions on the road ahead

 

Major Milestones 

Construction Start: Summer 2021

Activation: 

Soft launch occurred on June 16, 2022, when signs illuminated and displayed static speeds

Full activation occurred on June 22, 2022, when variable speed limits started to display