You may not notice if you haven't been paying close attention, but New Jersey’s gas tax went up 4.3 cents on Monday.

It’s the second time in as many years New Jersey motorists were hit with state-imposed price hikes at the pump. The latest increase is a legacy of a deal struck between former Republican Gov. Chris Christie and Democrats in 2016 to raise the gas tax by nearly 23 cents to pay for construction projects across the state.

More hikes — or possibly decreases — could come in the future.

Republican lawmakers have decried the latest increase, and one has introduced legislation to try to prevent it from happening again.

Here’s what you need to know.

Why the increase?

Language in the 2016 law requires annual changes to the gas tax to generate roughly $2 billion a year for the state’s Transportation Trust Fund, which pays for road repairs and projects to fix the state’s crumbling bridges and mass-transit system.

Over the past two years, lower-than-expected fuel consumption caused gas tax collections to miss targets set by the Christie administration. Under the law, the rate must be increased to make up for last year's $125 million shortfall.

Lawmakers wrote the law that way to prevent a repeat of the 2016 standoff over transportation funding that led to the Transportation Trust Fund running out of money.

Only after Christie froze most construction projects at the height of the summer construction season that year did Democrats and Christie strike their deal, which also included a reduction in the sales tax, elimination of the estate tax and other tax cuts.

New Jersey's gas tax had not previously been raised in more than 25 years.

Can Republicans block it?

Despite their displeasure, it's unlikely.

Now, as many did in 2016 when the first gas tax hike took effect, Republicans say the new expense will make New Jersey even less affordable for residents who are already struggling with high property taxes and cost of living.

“We can’t put tax increases on autopilot and expect that’s going to be OK with the people of New Jersey,” Assemblyman Jay Webber, R-Morris, said at a Thursday news conference.

Webber, who is locked in a tight race against Democrat Mikie Sherrill in the 11th Congressional District, called on Gov. Phil Murphy to suspend the 4-cent hike and introduced a bill, A-4516, that would end automatic increases in the future. He described the Transportation Trust Fund as “an absolute priority” but said the state should cut spending elsewhere to make up for shortfalls in gas tax collections rather than shifting the burden to drivers.

But Republicans can’t get much done without Democrats, who control both houses of the Legislature and the governor’s office. Democrats are not thrilled about the gas tax going up, either, but they have not expressed support for changing the law.

Will the gas tax ever go down?

It’s possible. Should fuel consumption spike one year, generating more than $2 billion for the state, the gas tax must be reduced, according to the 2016 law.

Some people are skeptical that will ever happen. As Webber pointed out, New Jersey used to have some of the cheapest gas in the nation, attracting customers from neighboring states. But that comparative price advantage has been eroded or erased by the recent gas tax hikes.

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“When you raise the price of something, people buy less of it,” Webber said.

If fuel-efficient or electric cars continue to grow in popularity, that could also cause fuel consumption in New Jersey to dip, triggering further increases in the gas tax.

How does New Jersey compare with other states?

Before 2016, New Jersey's gas tax of 14.5 cents was the second-lowest in the nation, higher only than Alaska's rate.

With Monday's increase, New Jersey’s gas tax will climb above 41 cents per gallon — among the 10 highest in the country, although still lower than neighbors New York and Pennsylvania, according to July figures from the Tax Foundation.

Email: pugliese@northjersey.com