A measure that would increase the penalty for protesting on freeways and airport roads is headed to Gov. Mark Dayton after the state Senate approved it Monday.

Senators voted 40-27 to strengthen the punishment, currently a misdemeanor, to a gross misdemeanor. That means people who take to freeways to demonstrate could face up to a year in jail and a maximum $3,000 fine. The proposal was spurred by protests in recent years in response to fatal police shootings of two black men, Jamar Clark and Philando Castile.

Dayton did not commit Monday to signing the bill. He said that because of safety concerns he supports stiffer penalties for people who block interstate highways and airport access. But he is also worried about infringement on constitutional rights to free assembly.

"I have to read the final language," Dayton said.

Sen. Bill Ingebrigtsen, R-Alexandria, urged lawmakers to pass the bill he sponsored. The House already approved the change, which was met with passionate opposition, largely from DFLers. In the Senate, a handful of DFLers joined with Republicans in support.

Protests that block freeways have inspired legislation to crack down on this strategy.

Ingebrigtsen said the change is necessary to deter protesters from creating "havoc" and dangerous situations for themselves and people in vehicles. He asked fellow senators how they would feel if their child needed to get to the hospital and died because they were stuck in traffic.

Sen. Jeff Hayden, DFL-Minneapolis, told fellow legislators that people take the extraordinary step of blocking freeways or airport roads because the government is not responding to injustices.

"When is it time for this country, this Legislature, this state to look out for the very people that are protesting?" Hayden said. "Where's that bill, Senator Ingebrigtsen?"

Star Tribune staff writer Judy Keen contributed to this report.