About 45 million vehicles in the United States now have transponders to pay tolls electronically, often without stopping or even slowing down, according to the International Bridge, Tunnel and Turnpike Association (IBTTA). Drivers pay $7 billion a year using those transponders.

Toll agencies running facilities from the Golden Gate Bridge to the Florida Turnpike in Miami are adopting “all-electronic tolling,” which eliminates toll booths altogether. Drivers either pay with an electronic device, or the agency bills them using information gathered based on a vehicle’s license plate.

The systems eliminate chokepoints at toll plazas and keep traffic flowing smoothly. But they also make it easier for drivers to get away with never paying a toll. With at least 115 toll agencies working in 34 states, there is a good chance the toll cheats never get caught.

Unless, that is, states work together...

That's what Maine, Massachusetts and New Hampshire are doing to collect money owed by their residents to other jurisdictions.

Forty-two percent of the revenue collected on New Hampshire’s toll roads comes from out-of-state drivers. So far, New Hampshire has recovered more than $180,000 from the owners of 190 vehicles over the course of the program, which began in August 2011.

Part of the reason why the collection numbers are so small is because about 70 percent of vehicle owners will pay their missed tolls after getting one or two invoices. Once the state prevents motorists from renewing their registration, officials say the state collects 95 percent of what it is owed.

According to NHDOT's Chris Waszczuk, “It’s not in the millions, but it is important to remember that it creates the expectation among the travelers that they will pay.”

Some systems are making progress. Drivers who have an E-ZPass transponder can now use it in 15 states, mostly in the Northeast, but also including Illinois and North Carolina. The effort started in 1990 with seven tolling agencies from New Jersey, New York and Pennsylvania. The E-ZPass system is now the standard for the region and states share all license data.

Similar efforts are underway in other parts of the country. Toll systems in large states such as California, Florida and Texas are improving cooperation. Oklahoma, which has the most miles of tolled road of any state, announced last week that its transponders would be compatible with those used in neighboring Kansas.

The key to collection, TollRoadNews.com reports, is that states must be inter-operational in the billing and not just the ticketing.

One of the most impressive features of the New England agreement is that the states apply their own penalties to their residents, rather than the penalties from the states where the violations occurred.

Maine and New Hampshire, for example, prevent people with outstanding toll debt from renewing their vehicle’s license plates during the annual registration process. But Massachusetts can prevent motorists from renewing their driver’s license and from renewing their registration for failure to pay.

Under the agreements, a New Hampshire resident who dodged Massachusetts tolls would be unable to renew his registration. But a Massachusetts resident who skipped New Hampshire tolls could have her license and registration renewals blocked.

Under the New England agreements, the states agreed to use thresholds similar to the ones where the motorists live. For example, Maine will pursue New Hampshire residents who have missed 20 or more tolls. But it will go after Massachusetts motorists who have racked up $10 or more of tolls.

The different enforcement mechanisms may explain why toll agencies have had more success collecting out-of-state revenue from certain states.

Maine, for example, has had far more success recovering money from Massachusetts residents than New Hampshire residents, said Erin Courtney, a spokesperson for the Maine Turnpike Authority.

Since February 2012, it resolved 73 of the 101 requests it sent to drivers in Massachusetts and recovered $26,300 of $29,100 it was owed. Among New Hampshire residents, though, Maine resolved 51 of 138 requests and collected $10,250 of the $28,400 it was owed.

The arrangement between Maine, New Hampshire and Massachusetts is one that is increasingly viewed as a model for many states across the county. As more states work toward reciprocity and share billing information, toll scofflaws will learn they can run, but they cannot hide.