SEATTLE, Wash. -

Tolls on Interstate 405 have collected 300 percent more than was predicted a year ago.

KING-TV reports that Washington State Department of Transportation reports show gross toll revenue on the interstate was $17.5 million. Initial projections were $5.5 million.

Total gross revenue for the highway was $21.6 million. That figure includes other income such as sales of "Good to Go!" passes, reprocessing fees and civil penalties.

In all, drivers took 10.1 million tolled trips and another 4.4 million free trips as carpoolers in the first year.

By law, revenue after expenses must be put toward I-405 improvements. Operating costs for the interstate were about $8 million.