FAIRFAX, Va. – Since the Interstate 495 Express Lanes have opened, some drivers have wondered whether using them will actually save time. Precise travel time is available on I-66 and I-95 in Virginia, but not on the Capital Beltway.
As the Virginia Department of Transportation unveils more travel times on I-66, the agency tells WTOP similar information near the 495 Express Lanes could be years away.
“We get our travel times from a company called Inrix, which uses GPS devices to come up with the travel times. Most of these GPS devices have a certain radius of accuracy,” says Hari K. Sripathi, Northern Regional Operations Director at the Virginia Department of Transportation.
The problem is the margin of error. Most commercial GPS systems are only accurate within 30 feet of a location. Normally, that’s not a problem. However, because the Beltway Express Lanes are up against the main lanes, the company is having trouble distinguishing between the two.
Gabe Goldberg of Falls Church says he would use the Express Lanes, but he wants to know that paying a toll will actually save him time on his commute. He gets frustrated when earlier this week he got onto the Express Lanes, only to find out there was no traffic on the main lanes.
“Once I get on to the Beltway, it’s too late. I’ve committed myself. With no information, my default position is to stay on the main Beltway,” says Goldberg.
“The idea that they (Transurban and VDOT) didn’t get around to planning to give people useful information to decide when to use the Express Lanes or main lanes is just folly.”
Sripathi says VDOT is exploring other technologies in Hampton Roads that could be useful, but would rather wait until GPS technology improves enough to get accurate information.
He admits the solution is “years” rather than “months” away.
“We want to work with travelers to understand what they’re looking for and how we can safely provide that information,” says Pierce Coffee, spokeswoman for Transurban.
But Coffee referred questions on the technical details on travel times to VDOT.
Even when technology improves enough, there’s another problem: how to provide the information.
Both VDOT and Transurban are already concerned about information overload. With so many signs and information bombarding drivers entering the Express Lanes, will travel times just add more confusion?
“If people are looking at too much information and not paying attention to the road, it can cause accidents,” says Sripathi.
“Also, when you look at the southern entrance near the Springfield interchange, everything is merging and then diverging. Drivers are already making a lot of choices very quickly. If we introduce travel time information on top of all that, we’re not sure that drivers will be able to read, comprehend and make an informed decision,” Sripathi says.
But Goldberg suggests putting them on arterial roads leading to the Beltway.
“Driving north on Gallows Road to the Beltway, I pass two big signs. The first is about half a mile from the entrance, listing prices to three points on the Beltway. They should put travel times on those signs,” he says.
The good news is that travel times will remain on I-95 when the Express Lanes open between Garrisonville Road in Stafford County and Edsall Road in Fairfax County in late 2014.
Meanwhile, new travel times have also been posted along I-66 this week.
East of Va. 234, with the travel time to the Vienna Metro
At the Fairfax County Parkway, with the travel time to I-495
Near U.S. 50, with the travel time to D.C.
At Sycamore Street, with the travel time to I-495
Before the Beltway, with the travel time to U.S. 50
West of Va. 123, with the travel time to Va. 234 Business
At Monument Drive, with the travel time to Va. 29 in Gainesville
Just west of the Fairfax County Parkway, with the travel time to Va. 29 in Gainesville
Just west of the rest area with the travel time to Va. 15 in Haymarket.
Sripathi says although the Inrix GPS program is unable to distinguish I-66 High Occupancy Vehicle Lanes from main lanes, similar to the problem on the Beltway, the overall data still appears to be accurate.
He adds that VDOT anonymously pings Bluetooth in cars to verify the travel times, although the data do not contain any personal information about the vehicle or the driver.