Riders Alliance members have a message for Governor Cuomo: Get serious about congestion pricing.

The state budget that was approved at the end of March created a panel called the Metropolitan Transportation Sustainability Advisory Workgroup that is supposed to address the New York region’s ballooning transportation concerns — including taking up the governor’s pricing proposal.

But with a January deadline fast-approaching, only the Assembly has announced its appointments to the workgroup. Governor Cuomo, Senate Republicans, Mayor de Blasio, and the MTA itself are all MIA.

Last year, Cuomo, without taking input from city or state lawmakers, recommended congestion pricing as part of his “Fix NYC” plan. The workgroup was intended to bring more parties to the table.

The governor plans to make his appointments “in the coming days,” spokesperson Peter Ajemian told Politico. For Riders Alliance, that loose commitment isn’t enough. They’re calling on Cuomo to appoint members by August 15 — the halfway mark between the budget’s passage and January 1.

“It’s up to you to now convene the Workgroup to refine the FixNYC proposal by adding the detail and incentives needed to win broad legislative support for congestion pricing in the next state budget,” several Riders Alliance members wrote in a letter delivered this afternoon to Cuomo’s Manhattan offices [PDF]. “The longer we wait, the more modernization will cost us and the more we and our 8.5 million fellow daily riders will suffer needlessly.”

The workgroup will eventually have 10 members: three appointed by the governor’s office, two by the Assembly, two by the State Senate, two by de Blasio, one by the MTA.