Drivers in New Jersey enjoy boasting about cheap gas in their state, where prices at the pump rank among the lowest in the country — so low, in fact, that thrifty motorists passing through often pull off the New Jersey Turnpike to fill up. The reason for the low prices is New Jersey’s relatively modest gas tax.

All that cheap gas carries real costs. Since gas tax revenues help pay for roads and public transit programs, the low tax has meant deteriorating bridges and pothole-strewn roads and ever higher transit fares that hurt working families.

The state’s road and bridges are “old, crumbling and getting worse every day,” the state’s transportation commissioner, Jamie Fox, recently told state lawmakers. Riders on New Jersey Transit are about to face a 9 percent fare increase, in part because the state’s Transportation Trust Fund, which helps subsidize that system and is supported by the gas tax, is about to go broke.

New Jersey’s gas tax is 14.5 cents a gallon. That compares with 44.46 cents per gallon in New York, 40.86 cents in Connecticut and 51.60 cents per gallon in Pennsylvania. A gallon of regular gas in New Jersey was $2.60 on average on June 12, much cheaper than $2.92 in New York. (Some experts say New Jersey gas would be even cheaper if drivers were allowed to pump their own gas.)