Drivers using the express lanes, on the left side of the Beltway, pay for a quicker, more reliable trip. (Dayna Smith/For The Washington Post)

[This post has been updated.]

Time is money, and the price is going up: The peak toll paid by drivers in the HOT lanes on the Capital Beltway topped $11 this month.

Tolls have been rising along with the traffic volume since the lanes opened in November 2012. The quarterly report from Transurban, the company that operates the 495 Express Lanes, says the variable toll reached $11.55 on April 3. When I checked late in the Tuesday morning rush, the toll for the entire 14-mile trip from Springfield to just north of the Dulles Toll Road was $11. But the toll from south to north is consistently much higher than the toll from north to south. Tuesday morning, the 14-mile trip south to Springfield cost $3.15.

April 3 traffic in Beltway express lanes Control room photo shows heavy traffic on April 3. (Courtesy 495 Express Lanes)

Michael McGurk, spokesman for the 495 Express Lanes, said the toll peaks usually tie in with extraordinary circumstances along the Beltway. “Weather, accidents or incidents are main drivers of really bad congestion from what we’ve seen,” he said in an e-mail. “If it’s a clear, sunny day, the regular congestion alone won’t push us to new highs.”

On April 3, when the northbound toll reached $11.55, a tractor-trailer crashed at the American Legion Bridge, backing up traffic on the inner loop to Springfield. McGurk sent along the photo at left, showing the view of the Beltway that appeared on the big screen inside the express lanes operation center. The regular lanes of the inner loop are jammed, and even the express lanes to the left of the regular lanes are unusually crowded.

Tuesday morning’s $11 peak was almost certainly influenced by the rain storms, he said. “We also had a couple of accidents in the Express Lanes network that drove up the density (we were still operating) and, therefore, toll prices. Southbound, there was an overturned vehicle in the general purpose lanes, but that didn’t drive congestion to the levels we saw in the northbound Express Lanes.”

The tolls vary with the traffic demand and the length of the trip. Many drivers don’t go the full 14 miles, instead using the access points at interchanges along the way. During the first quarter of this year, the average toll paid increased by from $2.32 in the last quarter of 2013 to $2.38.

The average number of workday trips during the January-March period was 37,969, according to the Transurban report. That was an increase of about 44 percent over January-March 2013.

While carpoolers can use the lanes for free as long as they have at least three people aboard and use the E-ZPass Flex transponder, about 91 percent of the trips taken during the past quarter were by toll payers.

The 495 Express Lanes, with its all-electronic tolling system and pricing that reflects the current demand, is the most complicated transportation system in the D.C. region. The peak rush hour toll is certainly enough to put off many drivers, but the basic technology can also be an issue. Transurban has estimated that 40 percent of the drivers on the Beltway don’t have E-ZPasses, a basic requirement of using the express lanes.

A driver who goes through without an E-ZPass will be charged an administrative fee. Drivers who go promptly to the HOT lanes’ Web site at can pay an administrative fee of $1.50. Drivers who want to dispute a toll can do that by looking for the “Missed a Toll?” button on the express lanes Web site. If the toll isn’t dealt with online within five days, the driver will receive a notice of toll due in the mail. At that point, the administrative fee rises to $12.50.

But you now know something many drivers don’t. When they pass under the toll gantries, there’s no signal telling them whether a toll has been recorded via an E-ZPass transponder, and there’s no sign along the highway telling them what to do if they think they haven’t paid the toll.

If a driver goes past the deadline for responding to the mailed notice, the fee will increase to $25. And it gets worse: If this eventually goes to a collection agency, the administrative fee goes up to $100 per trip. Ignoring the collection agency can result in a fine of up to $1,000.

Transurban isn’t interested in that. It wants satisfied customers who come back and pay more tolls, so the company issues periodic reminders about proper use of the lanes. You just can’t get all these details during the ride.