Thursday’s delays highlight strained transportation network
Published: October 9, 2009
An overturned utility trailer and its spilled cargo on Interstate 95 near Dumfries on Thursday afternoon caused traffic delays that lasted well into the evening.
The crash happened at 1 p.m. at mile post 151, before the start of the evening rush hour. One person was taken to a hospital with injuries that did not appear to be life-threatening, a Virginia State Police spokeswoman said.
But the eight or more miles of traffic delays the crash caused were serious enough to slow thousands of commuters.
While heavy traffic is not uncommon here, transportation authorities said that Thursday was an unusually difficult day for the region’s strained transportation network.
The delays grew to be so bad that some OmniRide commuter buses could not return to Washington to pick up additional commuters after their initial afternoon bus runs. That forced the transit agency to come up with a backup plan.
“Staff members met to decide which trips would be missed if absolutely necessary. Trips that run most frequently were selected to minimize disruption,” stated Potomac and Rappahannock Transportation spokeswoman Christine Rodrigo in an e-mail.
Several crashes along Dale Boulevard in Dale City also slowed local bus service and added to the delays that plagued OmniRide all afternoon, said Rodrigo.
The delays cleared sometime after 9 p.m., but many were left wondering how a car crash that happened hours earlier could affect so many commuters so late into the evening.
When a car on a highway slows down, stops or crashes, the subsequent interruption produces a ripple or shockwave effect that procedes from the point of the delay, slowing commuters for miles, said Philip Caruso, an engineer at the Institute for Transportation Engineers in Washington.
During crashes, emergency crews often close lanes to get cars around the crash and provide crews with enough space to help victims. This practice puts the squeeze on motorists and the highway itself, said Caruso.
“Picture a thin balloon with water flowing through it. Then if you all of a sudden squeeze it, the water builds up at a certain end of a balloon, forcing the water to show up somewhere else,” said Caruso. “It’s the same with traffic, as all the cars are herded into the only lane that’s open.”
Localities can help minimize traffic delays if they have a set response team designed to move crashes from travel lanes, he added.
The overall problem: Not enough transit options, said Northern Virginia Transportation Alliance President Bob Chase.
“You’ve got to create more alternatives to the 95 corridor, and one of the things that we pointed we need to build some kind of an eastern bypass that gets a lot of the traffic out of the 95 corridor that doesn’t want to be there,” said Chase.
The alliance, along with both chambers of commerce in Manassas and Prince William County, signed a declaration urging state lawmakers to pass new fees and taxes that would help alleviate transit congestion.
“The Northern Virginia region will add another million people over the next 30 years while the nation will add another 100 million people by the middle of this century. Most of them will live on the east coast and will move up and down through our region, and our existing transportation network is not capable of handling them,” said Chase.
Staff writer Uriah A. Kiser can be reached at 703-878-8065.