Use of the Interstate 35W MnPass lane has nearly doubled in three years, demonstrating on a second major freeway in the metro area that people are willing to pay for a faster trip.

Drawn by time savings and a reliable trip past the big bottleneck at the Minnesota River, 9,217 people have electronic toll accounts to use the I-35W MnPass lanes through Burnsville, Bloomington, Richfield and south Minneapolis, the state says.

With more users signing up each year, I-35W is on track to match the 12,800 account holders using Minnesota’s first MnPass lane, on I-394 between downtown Minneapolis and the western suburbs.

Last year’s extension of the northbound MnPass lane by two miles to the south from Burnsville Parkway has saved lane users from Lakeville and other points south 3 to 4 minutes by allowing them to get into the fast lane sooner, but no specific data is available about how many new riders the extension may have attracted.

MnPass lanes offer an express trip for bus riders, carpoolers, motorcyclists and solo drivers willing to pay a fee. Because they offer an alternative to sitting in traffic and move 50 percent more people than regular lanes during rush hours, the Minnesota Department of Transportation plans to start construction this year on a third MnPass lane on I-35E north of St. Paul that would open in 2015, said Brian Kary, freeway operations manager.

The department also is studying the freeway systems for opportunities to open MnPass lanes elsewhere, including I-94 between downtown Minneapolis and St. Paul; 35W north of downtown Minneapolis, and Cedar Avenue through Apple Valley, Eagan and Bloomington, Kary said.

The 35W MnPass lanes were initially built in the 1990s as carpool lanes as a compromise between suburban officials who wanted more lanes on the freeway and Minneapolis officials who wanted advantages for transit instead of more lanes.

But as carpool lanes, they were underused, and in 2009 they were converted to MnPass lanes, allowing solo drivers to take them for a fee. Before MnPass, about 2,000 vehicles used the carpool lanes going north on 35W over the river between 6 and 9 a.m. In 2010, after the lanes were converted to high-tech toll lanes, that increased to 3,500.

The number of users has not reached a plateau, but already the number of people — bus riders, carpoolers and toll payers — carried in the MnPass lane during rush hour is equal to the number of people carried in the other two general-purpose lanes combined, Kary said.

MnDOT’s latest counts from October through December of 2012 show that from 6 to 9 a.m. at the Minnesota River, the lane carries 4,333 carpoolers, 1,255 tolled drivers, 199 violators and 1,628 bus riders.

Tolls on MnPass lanes range from 25 cents to $8. The average toll is $1.50 to $1.75 and most people using the lanes are regular commuters who use it three times a week.