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Toll Plaza at Bay Bridge at night
E-ZPass and Fastrak are the future, apparently.
Thomas Winz—Getty Images/Lonely Planet Images

Massachusetts will be making the switch over to an all-electronic toll system in October by installing more E-ZPass readers and license plate readers.

For commuters in the Bay state, this is a good thing by and large. The high-tech toll system will mean people won't even have to slow down as they drive through the plaza—and that lack of a slowing and acceleration will reduce pollution from noise and emissions.

Besides the 400 toll workers who stand to lose their jobs—the state will be offering support in finding new employment—there is one major downside, however. The Western turnpike of Massachusetts may have 73% of drivers using the electronic system, according to MassLive.com, but plenty of people pay cash.

If you're driving your own car, this is an inconvenience for you and the state of Massachusetts. The license-plate readers will scan your plate and send a bill to the address where the car is registered, meaning you will have to deal with it later—and possibly track down the bill if you aren't going to be at your registration address. Ultimately this will cost the commonwealth of Massachusetts significantly: Since 2014, $1.2 million was spent mailing bills and $1.6 million went unpaid in tolls over the Tobin bridge.

Read More: 4 Tips to Avoid Road Tolls This Summer

But the real rub is for people who go through cash-less toll roads with a rental car. With no cash option, the bill—which can have administrative charges on top of it—will be sent to whatever address the rental car has on file. You can be sure the rental car company will give you another fat fee on top of the toll itself for the trouble. In fact, fees from Dollar and Thrifty were so high—$15 and $25 per toll—that they were served with class actions.

If you must rent a car in these areas, bring your own pass if you have one, and carefully consider your options when driving on toll roads.