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AASHTO Journal

Use of Weigh-In-Motion System at Idaho’s Inkom Port of Entry Seen Saving $2M a Year

The Idaho Transportation Department said the new "weigh-in-motion" automatic vehicle identification technology for big trucks that was recently installed at the Inkom Port of Entry in southeastern Idaho is expected to generate benefits for commercial vehicles using the scales, the general motoring public and local economies of about $2.1 million a year.

The ITD said about 3,100 commercial trucks use that port each day on Interstate 15 near Pocatello, and another 14,000 passenger vehicles pass by.

The agency estimated the annual cost savings to the industry based on both time and fuel savings, compared with the traditional system of having trucks pull into the weigh station and come to a stop on a scale while inspectors review the vehicle visually.

capitol0816.jpgWith the new system measuring the truck's weight along a lane as the truck continues to move, those that are compliant receive a message on a roadside sign telling them to proceed. The system allows commercial trucks that meet Idaho size and weight limits to bypass weigh stations at highway speeds, and the ITD estimates 50-60 percent of commercial traffic will be able to bypass the Inkom facility.

The ITD said this system also benefits other motorists, who should see less congestion in the area of the weigh station because fewer trucks will be required to pull in for processing and then slowly re-enter I-15.

"The possibilities are exciting," said David Hankla, who manages ITD Ports of Entry in eastern and southeastern Idaho. "The system has been fine-tuned compared to earlier installations, so the potential upside is tremendous."

The department previously installed similar systems at the East Boise Port of Entry, the Huetter weight station site in Coeur d'Alene, and at the Lewiston port. The Sage Junction facility in eastern Idaho, about 60 miles south of the Montana border, is slated for the next installation later this year.

The ITD said it completed the Inkom installation in late January, paid for mainly with a grant from the Federal Motor Carrier Safety Administration, while the ITD spent matching of $596,000 on building slabs and conduit runs to support scale installation and hardware for the system.

It uses sensor loops embedded in the roadway to track the movement of each vehicle through the weigh-in-motion system, which registers the vehicle's weight and axle configuration as it travels over the scales at highway speed. As truck drivers cruise down the highway, the electronic system verifies that the truck's legal weight, height, length, safety rating and credentials are in adherence with the law.

If everything checks out legally, the truck driver receives a green light on a transponder or a message on a changeable message sign directing them to bypass stopping at the weigh station and continue on the highway. If there are any legal issues, the driver receives a red light or direction to report to the weigh station for further inspection. In addition, truckers may also receive a red light for a random pull-in, the ITD said.

Using this allows facility staff to spend more time checking commercial vehicles for weight and safety violations, the agency said, while trucks that are operating safely and at legal load levels benefit by not being slowed with redundant stops as they make their way across the country.

And that can improve their bottom lines. "Economically, more freight moved more efficiently means better profit margins for the industries affected," the announcement said.

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