New System Will Shift I-76 Speed Limit Based On Traffic, Weather

PLYMOUTH MEETING, PA — A new technology system along I-76 will change the speed limit for motorists based on weather conditions, traffic, road work, and other factors, PennDOT announced this week.

A series of 72 digital signs were installed along a 14-mile stretch of oft-congested highway in Montgomery County, the stretch running between King of Prussia and Philadelphia. Called "Variable Speed Limit" and "Queue Detection Warning" systems, the technology will sense the number of vehicles on the roadway and will adjust speed limits

“These devices will help reduce congestion and greatly improve safety by warning drivers of changing conditions based on real-time expressway, traffic and weather events,” PennDOT Secretary Yassmin Gramian said in announcing the system's installation on Thursday. “This is one of the ways we are using operational strategies and technologies to actively manage travel and traffic flow along this critical corridor.”

This stretch of the Schuylkill Expressway serves roughly 130,000 vehicles per day. This stretch of road had 2,580 crashes between 2015 and 2019; 1,741 of them were rear-end crashes, PennDOT said.

The technology has reduced crashes by up to 30 percent in other states.

Specifically, the signs are installed between the Pennsylvania Turnpike interchange in King of Prussia, and the U.S. 1 North connection near the Philadelphia border. PennDOT is implementing a "testing period" for the new technology through May 10.

For the duration of the testing period, the signs will be fixed at 55 miles per hour in Montgomery County, and 50 in Philadelphia, matching the limits posted on roadway signs. The signs will also feature real-time warnings about lane closures, accidents, slowdowns, weather incidents, or any other conditions impacting traffic flow.

But starting on May 10, the roadway signs will be removed, and speed limits will vary significantly depending on traffic, ranging rom 35 to 55 miles per hour based on conditions, PennDOT said. This range may be adjusted depending on how PennDOT judges the performance of the system.

Into the future, authorities are working on other technological changes for this increasingly busy stretch of roadway. That includes modernizing traffic signals on other roads which feed onto the expressway, as well as turning the existing shoulders on portions of I-76 into third lanes during peak travel times.