The King County Library System plans to add parking space next year to the car-crowded Bellevue Regional Library with an underground parking structure beneath its existing surface lot.

Current designs show an additional 168 stalls to go along with 116 spaces in the existing garage.

The new structure will have two levels: one on the surface with a central vehicle ramp, and another below ground with pedestrian and vehicle connections to the existing garage.

Vehicles would enter the new garage through a sloping driveway located at the center of the surface lot, according to designs.

Existing lots at the library are generally filled to capacity during peak library hours.

“Inadequate parking is the main thing that’s holding back use of the building,” said Kay Johnson, associate director of facilities development for KCLS.

Overflow from the library’s existing lots typically goes to a city-owned parking area adjacent to the Ashwood playing fields, located just west of the library.

The library system has not come up with a solution for providing temporary parking while construction occurs, presumably next spring. However, KCLS is moving forward with the permitting process.

“We’re ready to go,” Johnson said. “We have the money, and we’re anxious to get started.”

KCLS is working with a budget of $4.5 million for the new parking facility. The money comes from a $172 million capital bond approved by voters in 2004.

Joshua Adam Hicks can be reached at 425-453-4290.