A proposed $200,000 study could look at whether Seattle should consider "congestion pricing" on some city streets in case drivers avoid tolls on the new State Route 99 tunnel.

The not-yet-approved budget request would look at the effects of putting tolls on the tunnel “and explore options, such as congestion pricing, to help manage impacts to local streets and transit travel times.”

The tunnel is set to open in 2019, but drivers are expected to avoid it so they don't have to pay the tolls -- similar to what happened when tolls started on the State Route 520 floating bridge.

Toll rates for the new tunnel have not yet been determined.

Seattle City Councilmember Mike O'Brien wants to study who will use the tunnel, who will avoid it, and what the city can do to make sure surface streets don't become too clogged to function.

"If more vehicles come into our city do we need more dedicated lanes for transit?" he asked. "If we do that, what does it mean for those people who are still driving? And who are those people who are still driving? Are they people who have no choice but to drive? Or could they take transit if we got them some good transit options?"

London is one of a handful of metropolitan cities around the world that implemented such a program to help mitigate traffic. Drivers pay a fee of 11.50£ a day (about $15), to access the city streets within the downtown corridor during business hours.

Mayoral candidates Jenny Durkan and Cary Moon have reportedly said the city should look at "congestion pricing" in downtown Seattle.

Several cities in Europe have zones where you must have a permit to drive in downtown areas. Not having a permit can result in steep fines.