LANSING, Mich. (AP) — Gov. Rick Snyder on Tuesday signed a $175 million influx of spending on Michigan’s deteriorating roads and bridges, urging pothole-weary drivers to be patient while a separate transportation-funding law continues to be phased in by 2021.

The extra infusion is 7 percent above current spending. It comes amid what officials say has been a punishing, wet winter for highways and streets, where holes and cracks have opened up amid seemingly constant freeze-thaw cycles.

“We’ve been suffering this for a generation or so. We’ve been doing something about it, but it takes time,” the Republican governor said before signing the supplemental budget bill in his Capitol office. Snyder, GOP legislative leaders and road officials stood beside orange barrels, construction signs and photos of crumbling roads that will be addressed with the new spending.

The legislation had sailed through the Republican-controlled Legislature, despite Democrats saying the spending is not nearly enough.

State and local road agencies were due to receive $2.5 billion for road and bridge work this fiscal year. Under the measure, they will get $175 million more — with the state and counties receiving 39 percent each and cities and villages getting 22 percent, per an existing formula.

The money, which was unspent lapsed funding from the last budget year, is a one-time boost while the state phases in a 2015-passed law to increase annual funding by $1.2 billion by 2021. That plan includes a mix of higher fuel taxes, vehicle registration fees and — starting later this year — annual transfers of general funds to the transportation budget.

“We’re not done. That’s not fully phased in,” Snyder said. “Could we always invest more? Likely. But we’re making tremendous progress.”

Yet the governor’s own infrastructure commission has warned that without more investment, road and bridge conditions will continue to worsen. It called in 2016 for another $2.2 billion to be allocated each year.

State Transportation Director Kirk Steudle said the $175 million will slow the deterioration of roads, but conditions will still “drop off” in the long term without more spending. “Every single penny helps,” he said.

Snyder, who is in his final year in office, suggested that other governments — not just the state — help to improve the roads. He said he supports an increase in the federal gasoline tax, which last occurred 25 years ago, and he noted that some municipalities have enacted local taxes for road improvements.

Democrats voted for the new spending after unsuccessfully trying to add more by pulling from the state’s savings account, but they criticized it as inadequate.

“Sending a few thousand extra bucks to a city that is riddled with potholes will not even begin to cover what’s really needed to get our roads in safe, drivable condition,” said Senate Minority Leader Jim Ananich of Flint.