This report documents Washington state's experiences with the FHWA's bridge weigh-in-motion system. The system was tested on four concrete bridges (one arched slab, one box girder and two pre-tensioned concrete girders) with moderate to heavy traffic volumes.
The system gave reasonable axle and gross vehicle weights under ideal conditions, but showed major limitations under high volumes. Over the life of the project, mean gross vehicle weight errors for individual trucks ranged between 11 and 18 percent with tandem and single axle weights having high mean errors. Errors for mean population gross vehicle weight estimates averaged two percent.