In the wake of a parts shortage that has kept more than 1,100 people waiting for months to get a MnPASS transponder, the Minnesota Department of Transportation said Wednesday that it's seeking a new vendor to supply the devices that deduct tolls from solo drivers who pay to drive in High Occupancy Toll lanes.

The move comes as MnDOT's contract with the Israeli firm that manufacturers the current transponders comes due and the agency begins taking steps to make MnPASS compatible with tolling systems in other states. That means motorists with MnPASS transponders could use them in places like Chicago and states on the East Coast and vice-versa.

A new vendor or more could be selected as soon as the end of the month, said MnDOT spokesman Brian Kary. But it could take as long as two years before MnPASS transponder holders could use them out of state or that holders of devices from, say, Illinois' I-Pass could use them here.

"We are getting set up to accept different readers," Kary said. "We are getting the hardware side ready. There is still policy and procedures on how to transfer the funds back and forth [between other states], but we are heading down that path."

MnDOT was going to have to make the change by 2016 due to a mandate from the Federal Highway Administration, but got the ball rolling earlier this year when it was unable to get clips from its lone vendor, Telematics Wireless. That left MnDOT with a short supply of transponders and forced the agency in February to curtail new signups.

About 500 people a month sign up for the program. There is currently a waiting list of more than 1,165, MnDOT said.

The clips are a key part of the transponder as it allows readers along the HOT lanes on I-394 and I-35W to electronically deduct tolls. Telematics Wireless told MnDOT the part had become obsolete, but was able to find replacement parts from a sub-vendor and since resumed production.

"That was upsetting to us," Kary said. "They told us at the last minute."

Drivers wishing to enroll in MnPASS were originally told they could sign up in April. On Wednesday, MnDOT was to have sent emails telling new enrollees that new transponders now won't arrive until late June or early July.

"People are anxious to get them because of the construction delays on Hwy. 12 in the area of I-494," said MnDOT spokeswoman Bobbie Dahlke. "People coming in from the way west want to bypass the congestion around the 494/394 area and want to use the MnPASS lane and can't."

With multiple vendors coming on board, Dahlke said it's unlikely there would be a repeat of the clip fiasco.

There are currently about 25,000 customers who have transponders, and that's a number likely to rise when signups begin this summer ahead of the opening of the new HOT lane later this year on I-35E through St. Paul and Maplewood.

Current MnPASS holders will be unaffected by any changes in the system, even as new readers and equipment are installed, Kary said.

"They won't have to trade out their transponders," he said.