Eager to offset the traffic nightmare posed by construction on the Springfield Interchange, Prince William officials have asked the Virginia Department of Transportation to expand and hasten the building of several commuter parking lots.

The county plan approved yesterday would add about 1,500 commuter spaces to lots along the Interstate 95 corridor. VDOT says tie-ups caused by the construction could add 30 to 60 minutes to the typical commuter's trip--each way.

Funding the proposed changes--on top of parking lot expansions that are already slated for the area--could pose a problem for the county, which wants to open all these new lots by spring 2001. The changes require not only speeding up some construction but devoting about $12.3 million to county commuter lots. Only $4.8 million is currently allocated in VDOT's six-year plan for such spaces, and the county does not plan to use any of its own money.

At least 4,000 commuters currently use parking lots along I-95, many of which are overflowing, said Eric Marx, director of planning for the Potomac and Rappahannock Transportation Commission.

Parking spaces are especially threatened by the prospect of a store relocation at Potomac Mills Mall that would take the place of a 700-space parking lot. The loss of such a large number of spaces, possibly as soon as winter, would be devasting to area commuters.

The county has been approached by representatives from Potomac Mills and from the site of the former Incredible Universe store who say they would consider building a 704-space parking deck at a cost of $7 million. The county wants to hurry that plan along, and VDOT has expressed interest in helping fund the project.

An expansion is already planned for a 730-space commuter parking lot at Horner Road off Prince William Parkway. The county would like to increase the number of parking spaces by 750, instead of 325, and push forward the completion date from summer to spring 2001.

The county also wants VDOT to look at placing an additional ramp from the I-95 high-occupancy vehicle lanes to a commuter lot at the Route 123 and I-95 interchange, where access improvements already are planned because a 690-space there lot is underused.

Another proposed improvement involves demolishing the old Hechinger Co. building at Old Bridge Road and Route 123 to increase a 400-space parking lot by at least 225 spaces. And a temporary, 250-space lot planned at Routes 234 and 1 would be replaced by a permanent one under the county plan.