I-66 Express Lanes tolls spike to $34 after going into effect Monday

A major expansion of northern Virginia's network of toll roads is now up and running and some drivers using the Express Lanes on Interstate 66 inside the Capital Beltway faced higher than expected estimated charges to drive on the roadway.

The launch of the Express Lanes allows drivers to use Interstate 66 for free as carpoolers and for a variable toll as solo drivers. The highway remains free for all users outside of rush hour.

Similar Express Lanes are already in place on the Beltway in Virginia and on Interstate 95.

RELATED: I-66 Express Lanes: What You Need To Know

"Prices for a trip along the entire nine-mile corridor ranged from $4.50 at 5:36 a.m. to $34.50 at 8:36 a.m.," the Virginia Department of Transportation (VDOT) said in a news release. "Each price remained for six minutes (toll prices are updated every six minutes). As traffic volumes climb, the system responds by raising the toll price to help manage the number of vehicles getting on the roadway, to keep the traffic flowing freely. The price is an indication that the system is becoming fuller and fuller."

FOX 5's Melanie Alnwick reported that the Virginia Department of Transportation initially reported that the average toll was going to be $5 or $6 depending on how far someone traveled. When she checked this morning, she also saw high estimated tolls of $21 at 8:16 a.m.

"The tolls are dynamic," said VDOT's Michelle Holland. "It's based on the volume of traffic and the number of drivers that are willing to pay the toll."

"Now, early in the morning, it was $4.50. I was told for six minutes, it hit $34. But when those dynamic tolls go up, what they are trying to tell you - don't go on the lanes." said Virginia Gov. Terry McAuliffe.

Holland said that the prices seen Monday were in line with what they expected for peak rush hour. She said it could take several months to determine what the average rush hour prices will be.

Holland said that EZ Pass Flex Pass users need to switch over to the HOV mode before beginning their trip or a violation could be triggered. Driver who drive the lanes without and EZ Pass would be made to pay the price of the toll plus a $12.50 fee. Holland said law enforcement officers will look for solo drivers who have their devices set to HOV mode and a fine of $250 could be given.

During the four-hour period, about 11,000 vehicles passed through the Dulles Connector Road merge to the eastbound 66 Express Lanes, which is the most heavily traveled point on the lanes," VDOT said.

The state agency also added, "Average speeds on this segment of I-66 were 57 miles per hour, compared with an average of 37 mph at last year this time. Average travel times were 10-12 minutes for the I-66 corridor during the morning rush hour, compared with a range of 15 to 25 minutes during a typical Monday morning period."

During the evening rush hour, FOX 5's Gary McGrady says tolls on the westbound lanes of I-66 were hovering around $6 to $8.

The Express Lanes will be in effect Monday through Friday from 5:30-9:30 a.m. in the eastbound direction, and from 3-7 p.m. in the westbound direction. Outside of these times, the lanes will be free for everyone.

Drivers can check the estimated tolls on I-66 on vai66tolls.com or the 66 Express Lanes app for Apple's App Store and Google Play.

The Associated Press contributed to this article