The U.S. Senate sponsors of legislation governing self-driving cars are searching for an expedited way to get a floor vote after momentum on the bill stalled in recent weeks.

Senate Commerce Committee Chairman John Thune, R-S.D., and top Democrats are pulsing members on both sides of the aisle to see whether there are any concerns that might hamper a vote using the unanimous consent rule, two people familiar with the matter said. It’s the first step toward getting the Senate’s full consideration of the bill after it unanimously was voted out of Committee on Oct. 4.

The measure notably bars states from imposing restrictions on autonomous vehicle safety performance and development, allows automakers to win tens of thousands of exemptions from safety rules that require human controls, and sets privacy requirements for disclosing how collected data is used.

Thune told Bloomberg BNA that his staff is informally checking with Republicans to identify and resolve any concerns before the bill comes to the floor.

Co-sponsor Gary Peters, D-Mich., is doing the same thing on the Democratic side in an effort to pass the bill under unanimous consent, a Senate staff member toldĀ Automotive News.

A senator may request unanimous consent to set aside a specific procedural rule to speed up proceedings, but it only takes one objection to kill the request. The principle behind the rule is that procedural safeguards designed to protect a minority can be waived when there is no minority to protect.

Auto and tech industry officials were optimistic the Senate would pass autonomous vehicle legislation this year, but the timing of a potential vote remains unclear with the Senate focused on a massive tax cut bill, budget matters and immigration issues.

Lawmakers will have to make a final Senate bill compatible with a similar bill that has already been passed in the House.