A Sound Transit spokesman said the fee would make parking more efficient and help with overcrowding in the lots.
Even on a Sunday afternoon, drivers scrambled to find parking at the Tukwila park-and-ride, which is one of the four lots Sound Transit will use in a pilot program to address overcrowding.
The others include the Sumner Station, Issaquah Transit Center and Mukilteo Station.
"What the board said was we want you to look at how we can better manage our parking and get more people on our trains and buses per stall," said Bruce Gray of Sound Transit.
As part of the proposal, drivers at the testing sites will pay to park. The fee will be $5 every four months for carpoolers and $33 every four months for single drivers.
The transit passengers would then get a placard that gives them designated spots to park in.
"This is a way to free up spaces so there may be a little more room for people who need to get to the station and take transit from there," Gray said. "And more than that, we want to get more people sharing rides to the stations and then getting on our buses and trains."
Some drivers say the additional cost could keep them from using the transit system at all.
"It depends though. If it's what we pay downtown I wouldn't, because that's the whole point of parking down here -- not taking a car in town and saving money and gas and energy and all that stuff," one transit user said.
The program would also give drivers a chance to go online and see which lots are full before leaving home.
Sound Transit will soon begin outreach efforts at the four proposed locations, and they hope to launch the program by next spring.