Update: Tony Avella and Diane Savino have backed the 25 mph bill, leaving it up to Republicans Marty Golden and Andrew Lanza to convince Senate Co-Leader Dean Skelos to hold a vote on the bill.

Lowering New York City’s default speed limit from 30 to 25 mph depends on the votes of a handful of key state senators tomorrow, the final day of the legislative session. Senate Co-Leader Jeff Klein expects his bill to come up for a vote, according to WNYC, but the measure could become a victim of party politics.

The senators to keep an eye on are Marty Golden, Andrew Lanza, Tony Avella, and Diane Savino. None of them have responded to Streetsblog’s requests for comment. Golden and Lanza, the city’s two Republican senators, will likely determine the ultimate position of Senate Co-Leader Dean Skelos of Long Island.

As members of the Klein-led Independent Democratic Conference, Avella and Savino occupy important spots in the Senate. Avella came out against an earlier 20 mph bill but hasn’t said anything about the 25 mph legislation now up for debate. Savino hasn’t said anything publicly, either, but reports from late last month indicated that she might back the bill.

You can contact the senators at their Albany offices:

• Marty Golden: (518) 455-2730 and @SenMartyGolden
• Andrew Lanza: (518) 455-3215 and @SenatorLanza
• Tony Avella: (518) 455-2210 and @TonyAvella
• Diane Savino: (518) 455-2437 and @DianeSavino

Skelos, who shares power with Klein in a day-by-day agreement, remains noncommittal. “I don’t know if it will be on the floor. It is certainly one of the things we will be discussing,” he said, according to the Daily News. “I know how important it is to Mayor de Blasio and he’s certainly one of my best friends.”

Mayor de Blasio, you may remember, brokered an endorsement deal with the Working Families Party in which Governor Cuomo came out in favor of Democratic control of the Senate, a shift that would cost Skelos his position atop the chamber. Best friends, indeed.

Things are more certain in the Assembly, where there are two bills waiting in the wings with the backing of Speaker Sheldon Silver. One is a comprehensive 25 mph bill that makes it easier for the city to expand 20 mph zones. The other is an identical copy of Klein’s Senate bill. Earlier today, according to Capital New York’s Jimmy Vielkind, Silver said there were significant differences between the two bills and that the houses had not come to an agreement.

But Daniel O’Donnell, the original sponsor of speed limit legislation in the Assembly, told Capital New York that he would be willing to move on Klein’s version, if it survives the Senate. “I’m uncertain whether or not Mr. Klein can get his bill passed. If the Senate’s going to move a bill, we’ll move that bill. If not, I’ll move on a bill that the city’s been asking for since January,” he said.

For its part, the city has said it will take either version of the legislation. This morning, the City Council voted 38-2 for a home rule message from the mayor backing Klein’s bill. Last week, it voted 40-4 for a home rule message on the Silver-O’Donnell bill. Republicans Steven Matteo and Vincent Ignizio of Staten Island opposed today’s measure; they were joined last week by Eric Ulrich of Queens, who was absent today, and Jumaane Williams of Brooklyn, who voted in favor this morning.