SEATTLE -- Tolls for the 520 Floating Bridge will start as early as November 2010 and no later than June 2011, documents from the Washington State Department of Transportation revealed.

The state wants to replace the aging bridge with a new, bigger one that will cost $4 billion.

In the report found online, the state's panel of experts worries about the costs of enforcing tolls -- chasing thousands of drivers into court who only cross a few times a year.

WSDOT is seeking bids from contractors to operate its statewide tolling customer service center. Contract proposals are due by the end of September.

WSDOT said it is using an incentive program that encourages vendors who are bidding for the job to open the center as soon as possible. The sooner they propose to open it, still between November 2010 and June 2011, the more incentives they can earn. The contractors also will face fines if they fail to meet the contracted completion date.

Incentives for early delivery call for $100,000 per week with a cap of $3 million. The liquidated damages will cost the chosen vender $350,000 for every week they overshoot the contracted completion date.

More information on the customer service center request for proposals can be found at: www.wsdot.wa.gov/Business/Contracts

The expert panel is concerned that the state Department of Transportation did not have enough time to implement the system correctly if tolls were to start as planned in October of 2010.

Because toll booths would slow down traffic, planners want a non-stop all-electronic toll system. Drivers will use the Good to Go system that's in place on the Tacoma Narrows Bridge and the state Route 167 HOT lanes.

The Seattle Times reported the cost of the eight-month delay is almost $24 million.