Reservations for travelers on the Clinton-Mukilteo ferry route would be limited to commercial traffic, according to a pre-design study on a reservation system conducted by the Washington State Department of Transportation.

The report recommends that most of the ferry terminals in the Washington State Ferry system adopt a reservation system that covers all travelers, however. Those terminals include Anacortes, Bainbridge, Bremerton, Edmonds, Friday Harbor, Keystone, Kingston, Lopez Island, Orcas Island, Port Townsend, Seattle, Shaw and Sidney.

Terminals that would have reservations for commercial traffic include Clinton, Mukilteo, Point Defiance, Southworth, Tahlequah and Vashon Island.

The pre-design study was transmitted to the Legislature on Tuesday, and made available to the public on Wednesday. The Legislature will eventually decide whether or not to approve a reservation system, modify the approach outlined in the study, or reject the proposal.

A reservation system for the Clinton-Mukilteo run has been bitterly opposed by many South End residents. Critics have said it could hurt tourism and the ability of those who need to commute off-island for work. Opponents have also said return trips to Whidbey Island from the mainland are sometimes difficult to predict due to traffic and other factors, so making reservations would be especially problematic.

Officials from Washington State Ferries say reservations are needed because they will help level out demand on the ferry system during peak travel times, which will lessen the need to build larger terminals and more vessels.