Truck Scales

The main exit off of I-95 to my home is just after a truck scale. It can be darn annoying to have to let trucks merge back in to traffic just as I'm preparing to exit. A lot of trucks. Some days it seems there's more trucks on the road than cars. It also used to really bug me that it looked like 90% of those trucks had been directed into the scale exit only to be diverted into their pass-through area instead of stopping to be weighed.

The other day I actually learned something from the newspaper!! (gasp)

DMV spokeswoman Pam Goheen:

"DMV weighs approximately 3 million trucks at the Dumfries weigh station each year. To handle the volume of truck traffic, the department has installed multiple layers of technology to safely manage traffic past and through the station.

"First, we have installed on I-95, upstream of the station in each direction, a mainline electronic screening system. The system, which is imbedded in the highway, takes the physical dimensions of each vehicle (weight, axle spacings, speed) as well as the vehicle's transponder ID. With this information, the system determines if the vehicle is in compliance with all weight, safety and credential requirements. If in compliance, the vehicle is signaled via its transponder to bypass on the mainline without having to enter the weigh station at all. This screening program is operated in conjunction with a company called PrePass. Carriers must have a PrePass-issued transponder on board to be eligible to bypass. This is a voluntary, fee-based transaction between the carrier and PrePass.

"Secondly, DMV has a weigh-in-motion (WIM) system installed in the entrance ramp. All other vehicles that are not bypassed by the mainline are required to enter the weigh station where they are screened for weight by this ramp WIM system. If the vehicle is in compliance with the weight laws, it is directed via an overhead traffic signal to the bypass lane to exit the station. If the vehicle is not in compliance, it is directed to pull onto the static scales for further inspection.

"Finally, DMV has static scales where we weigh each vehicle that did not pass the ramp WIM screening process.

"All vehicles that travel on I-95 when the station is open are checked for weight. DMV is maximizing technology to safely manage traffic through and past the station."

Made me feel a lot better about that silly truck scale. Let's see here ... about 3 million trucks weighed each year at that scale. Let's assume half are northbound and half are southbound. Let's assume the daily distribution is equal, all 365 days of the year. So 1.5 million / 365 = 4,110 trucks weighed on each side of the highway EVERY DANG DAY. If the average truck/trailer combo is 40 feet (some are more some are less), then this scale processes about 31 solid (nose to butt) miles of trucks in each direction every day.