Choosing a Weigh Station Bypass System

Weigh stations are a fact of life for fleets and their drivers. Pulling in for inspections can cut into drivers’ precious driving time and cause delays, which may have negative effects on a fleet’s operating cost.

While fleets can’t eliminate weigh stations, there are technologies that may allow qualified carriers and trucks to bypass inspection sites to save money and time.

Before choosing a bypass system there are a few things fleets need to understand. The first is the difference between the primary technologies used for reading and relaying truck information to the weigh station:

  • Radio frequency identification (RFID), which uses a transponder mounted inside the windshield
  • Commercial Mobile Radio Services (CMRS) uses cellular phone technology for identification through mobile devices.

The difference between the two systems is the method and accuracy with which the signals are transmitted between weigh stations and trucks. RFID transponders transmit and receive signals with near 100% accuracy, while CMRS applications can drop signals depending on terrain, weather, the quality of the cellular service provider, the type of device and the quality of the GPS chip set. Prior to selecting a bypass technology, fleets should consider the terrain and cellular coverage on their routes.

Another factor to consider in the selection process is the number of service locations that feature each provider’s bypass technology. Not every location accepts or uses RFID and/or CMRS provider services. Also, be sure to understand how the provider defines the two different types of weigh stations. Both technologies provide enforcement with the ability to create mobile sites along the highway. Instead of considering the number of possible mobile sites (which may be included in the provider’s location count), compare the number and locations of fixed weigh stations through each provider.

Fleets also need to consider weigh-in-motion scales (WIMs) that are embedded in the roadways. WIMs screen a truck’s weight and transmit a signal as the vehicle approaches the weigh facility. In most cases, RFID transponder-based bypass systems are better suited for accurately reading WIM weights and matching them to the correct vehicle.

Another benefit of RFID systems: they allow the integration of electronic toll payment services. Only RFID transponders are authorized for electronic toll payments. Regardless of how often a truck has to pay tolls, having a truck bypass system that also handles toll payments is a major cost saving benefit.

Overall, cost savings should be a significant factor in a fleet’s bypass system selection. In one case study, a fleet of 325 trucks saw significant savings by using a RFID bypass system. In one year the company’s trucks received green lights to bypass weigh stations 94.35 percent of the time for a total of more than 30,800 bypasses. That saved them 12,000 gallons of fuel and nearly 2,600 hours of productivity. Total savings in operating costs for the fleet was $154,000.

Weigh station bypass systems can do much more for a fleet than save time and money on the road. Some systems, like PrePass’ InfoRM, offer reporting tools to help improve the fleet’s safety performance by providing detailed data to break down the factors influencing a fleet’s Inspection Selection System (ISS) score.

Finally, although RFID transponder technology for bypass is more reliable, there still is a place for CMRS. As long as cellular coverage is strong and the state does not require WIM weights in its bypass decision, this solution can be effective for fleets with simple bypass needs.


HELP Inc. is a non-profit public/private partnership between trucking company leaders, enforcement agencies and state DOTs to improve highway safety and efficiency. HELP’s Board of Directors is comprised of an equal number of industry and public executives to maintain a balanced perspective on the issues impacting the trucking industry on our nation’s highways. To date, HELP has invested more than $600 million to deploy PrePass weigh station bypassing, weigh-in-motion scales, PrePass Plus electronic toll payment and other innovative truck safety technologies across the United States to improve safety, reduce truck-related emissions and preserve highway infrastructure.



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