SEATTLE — A new draft study from Washington State Ferries suggests vehicle reservations could be offered on some ferry routes.

The proposal released this week envisions a reservation system on three central Puget Sound routes in 2015. Those are Seattle-Bainbridge, Seattle-Bremerton and Edmonds-Kingston.

Reservations on the Anacortes-San Juan routes could begin as early as 2011.

The study says terminals on the Southworth-Fauntleroy, Tahlequah-Vashon and Mukilteo-Clinton routes don’t have adequate vehicle holding areas and they would be excluded.

The report says a reservation system would reduce wait times, reduce traffic congestion near terminals and cut air pollution from idling vehicles.

It would cost about $26 million but the ferry system says it would eliminate the need to expand terminals and holding areas, an expense estimated at $290 million.

A final report on the proposal will be sent to the Legislature next month.