An in-stream weighing platform was designed and installed in the eastbound lane of I 64 and 75 near Lexington, Kentucky. The broken-bridge scale platform was designed with the outer edges of the two sections supported on hinges and contiguous edges supported by two 20,000-pound capacity load cells. The assembled scale measures 4'-6" x 10'-1/2" with a total weight of about 2,000 pounds.

The electronics developed for the system included digitizing circuitry which processed the load cell signals and recorded the data on digital magnetic tape. Computer processing of the field data produced tabular information on vehicle speed, axle spacing, number of axles, vehicle classification, time of day, and weight for each vehicle, as well as voluminous statistical data such as average daily traffic and equivalent axleloads.

Conceptually, the system was good, but numerous electronic and mechanical problems compounded to render the present system inoperative. Future dynamic weighing system designs should consider portable, lightweight scales and electronic instrumentation suitable for mounting in a vehicle, thus providing a flexible data-gathering system that will be more readily maintainable. Immediate data output in the field would be highly desirable.

Report Date


Report Number

No. 307

Digital Object Identifier



The opinions, findings, and conclusions in this report are not necessarily those of the Department of Highways or the Federal Highway Administration.