Office of Operations Freight Management and Operations

5.0 Summary of Benefits and Costs

5.1 Benefits

While no formal evaluation of VWS has been completed, anecdotal information and evaluation results from deployments of similar roadside applications provide examples of the wide range of benefits that likely will accrue to public and private sector stakeholders by VWS.   These benefits include:

  • Increased protection and preservation of pavement and the nation’s infrastructure—Overweight trucks are estimated to cause hundreds of millions of dollars in damage to the nation’s roadways each year.  Virtual weigh stations have the potential to dramatically reduce the damage done to the roadways by overweight vehicles operating illegally (i.e., without a valid OS/OW permit) by expanding the geographic scope of the nation’s truck size and weight enforcement programs and deploying enforcement assets into areas currently not monitored by fixed or mobile enforcement resources.  Recent research indicates that an 80,000 pound commercial vehicle has the equivalent single axle load (ESAL) value of 26,000 passenger vehicles, while a 100,000 pound commercial vehicle has the same ESAL value as 70,500 passenger vehicles. (American Association of State Highway Transportation Officials (AASHTO), Virtual Weigh-in-Motion:  A “WIM-win” for transportation agencies,, February 2007.) As such, every illegally operating, severely overweight (at least 20,000 pounds greater than the legal limit) truck that can be removed from the roadways has the same impact on the infrastructure as removing 44,500 passenger vehicles from the traffic flow.  State estimates suggest that reducing the number of overweight trucks will save tens of millions of dollars.  Arizona estimates that overweight trucks cause $12 million to $53 million in damage to the State’s infrastructure annually. (Eric Volante, “Overweight Trucks Damage Roads, Bridges,” The Arizona Daily Star, September 11, 2007.) A similar study conducted in 1999 found that overweight vehicles in Texas caused an estimated $6 million to $48 million in damage to the State’s roads and bridges annually. (“Keeping overweight trucks from getting a-weigh,” Texas Transportation Researcher, Volume 35, No. 3.) In addition to reducing this excessive damage to the nation’s infrastructure, virtual weigh stations also may increase overall compliance with size and weight regulations because commercial vehicles may be unable to avoid enforcement resources as easily in the future and their operators will therefore be more willing to “voluntarily” comply.
  • Increased efficiency of enforcement assets—Enforcement personnel continue to be overwhelmed by the number of commercial vehicles operating in the United States and the volume of trips made by these vehicles.  Between 1990 and 2006 (the most recent year for which data is available), vehicle miles traveled by large trucks increased by 53 percent and the number of large trucks registered in the United States increased by 42 percent. (Large Truck Crash Facts 2006, Federal Motor Carrier Safety Administration, January 2008, page 4.) The sizeable increase in the number and volume of commercial vehicles to be regulated occurred without a corresponding increase in enforcement personnel.   As a result, the time between inspections and roadside weighings of commercial vehicles has increased.  Further, the potential for a commercial vehicle to avoid enforcement has increased in recent years as commercial vehicles elect to use bypass routes to avoid fixed inspection stations and are less likely to encounter mobile enforcement personnel.  Virtual weigh stations have the potential to address these issues by extending a State’s enforcement program to bypass and secondary routes and focusing its limited human enforcement assets on commercial vehicles that are known to be overweight or have other increased risk factors (e.g., operated by a carrier with a poor history of safety performance).  In addition, VWS data can be used to more effectively schedule enforcement resources and ensure that human assets are deployed at locations/days/times when data indicates there is an increased occurrence of overweight trucks.  This improved efficiency of enforcement personnel also will benefit legally operating commercial vehicle operators because it will serve to “level the playing field” and ensure that some operators are not deriving an unfair competitive advantage by operating illegally.
  • Improved highway safety—The recently completed national evaluation of the Commercial Vehicle Information Systems and Networks (CVISN) program included an in-depth analysis of the safety benefits that could be derived from the increased use of roadside enforcement technologies and the increased targeting of commercial vehicle operators with histories of poor safety performance.  This analysis revealed that the nationwide deployment of roadside technologies (e.g., infrared brake testers, safety algorithms associated with high driver OOS rates) could result in as many as 17,907 fewer crashes and 215 fewer fatalities per year than if the inspection selection process was based solely on manual (human) screening. (CVISN National Evaluation Report, Volume 1, Federal Motor Carrier Safety Administration, 2008, page 7-13.) Expanding the number of technology-equipped sites through the deployment of virtual weigh stations with expanded functionality should directly support these safety results.
  • Improved operations/turnaround time—As part of the national CVISN evaluation, 848 motor carriers were interviewed to document their experiences using CVISN services, including the program’s electronic screening functionality.  Similar to VWS, electronic screening targets enforcement resources at high-risk commercial vehicles based on a series of screening factors (e.g., weight, safety performance) and roadside technologies (e.g., WIM, AVI).  Nearly 98 percent of motor carrier respondents indicated that they had experienced “reduced delays” based on their participation in the program.  Nearly 80 percent of motor carrier respondents also reported reduced labor costs associated with their use of electronic screening. (CVISN National Evaluation Report, Volume 1, Federal Motor Carrier Safety Administration, 2008, page 5-13.) Based on the similarity of the VWS and electronic screening concepts, a similar percentage of motor carriers interacting with VWS likely will derive operational benefits from this technology.
  • Improved freight data for planning—Having access to accurate data regarding the movement of commercial vehicles across the transportation system is a key component of effective and accurate transportation planning, especially freight planning.  These data are used to identify corridors that support commercial vehicle traffic, as well as to provide inputs to travel demand models that forecast the impact of a change to a region’s infrastructure.  The freight planning community currently is beginning to use data from wireless technology providers (e.g., satellite, cellular) to capture vehicle-specific movements, as well as general corridor-level freight flows and/or system performance.  Virtual weigh stations, especially those with expanded functionality, have the potential to generate and provide this type of data to planners and those responsible for overall system performance.
  • Improved air quality— Idling long-haul trucks are estimated to “consume 20 million barrels of diesel fuel and generate 10 million tons of CO2, 50,000 tons of nitrogen oxides, and 2,000 tons of particulates annually.” (Argonne National Laboratories, “Reducing Heavy Truck Idling,” While most of this environmental impact is caused by commercial vehicles idling overnight, the targeting of enforcement resources at high-risk motor carriers and commercial vehicles should reduce air quality costs associated with trucks idling while waiting for roadside inspections.  The PrePass electronic clearance program estimates that over 309,000 metric tons of carbon emissions have been prevented through its bypass program, which currently is deployed at over 280 sites and has 413,224 commercial vehicles enrolled. (PrePass website,, June 18, 2009.) A nationwide deployment of similar technologies (i.e., VWS) has the potential to substantially increase these benefits.
  • Improved asset tracking—VWS technologies and other roadside enforcement technologies can generate the requisite data (e.g., vehicle identification, date, time, location) to allow a motor carrier to track its commercial vehicles’ movements.  To date, motor carriers have expressed minimal interest in accessing VWS data for the purpose of asset tracking because 1) they already use private sector service providers for this function and 2) there are concerns about timeliness and robustness of the data.  As VWS is deployed more widely, motor carriers may express an increased interest in this functionality.

5.2 Costs

VWS is a low-cost alternative to expanding a State’s truck size and weight enforcement program.  Costs associated with VWS deployments vary by the scope of the VWS being deployed, the amount of existing infrastructure that can be leveraged by a State, as well as the type of technology being deployed.  Based on requests to FMCSA for Federal CVISN Deployment funds, estimated costs of recent VWS deployments are between $300,000 and $1,400,000. (Data is from State applications for Federal CVISN Deployment Grant applications, Fiscal Years 2006-2008.) Even the high-end costs are much lower than the costs associated with building a new fixed weigh station, which typically costs $12 million but can cost as much as $300 million if land acquisition is required.   

5.3 Available Funding Sources

Various funding sources are available to support the deployment of VWS.  These funding sources include:

  • Federal-Aid Highway Program (FAHP)—Deployment of WIM systems in conjunction with a VWS deployment may be an eligible FAHP expense.  FAHP funding eligibility is determined by the primary intended purpose and use of the WIM.  Construction of WIM systems “that directly facilitate an effective vehicle weight enforcement program” are eligible for FAHP funding as defined under “construction” in Section 101(a)(3)(H) of Title 23, United States Code (USC). 
  • State Planning and Research (SP&R) programWIM systems that are built to primarily support the statewide traffic monitoring program for uses including analysis of travel and weight trends, pavement and bridge monitoring and management, and pavement design, qualify for funding through the State Planning and Research (SP&R) program.  These WIM sites can be used secondarily by enforcement personnel for resource planning and commercial vehicle weight screening.
  • Commercial Vehicle Information Systems and Networks (CVISN)—In the past few years, over a dozen states have used Federal CVISN Deployment Grant funds to implement virtual weigh stations.  Among components of the virtual weigh station that are eligible expenses for CVISN funding are WIM scales, cameras, OCR technology, system electronics, screening software, and system integration.  A State’s CVIEW system, which is an eligible CVISN expense, also can serve as a key data repository in support of VWS deployments (e.g., serve as a database of motor carrier and commercial vehicle safety and credentials data that can be queried by the VWS screening system, serve as a repository for data collected from the VWS).  CVISN funds also can be used to support expanded communication networks to support the timely and secure transmission of virtual weigh station data to users, as well as integration of safety data/screening algorithms into roadside operations.

Many states’ WIM systems originated as part of FHWA’s Strategic Highway Research Program (SHRP) or Long-Term Pavement Performance (LTPP) Program.  These programs, focused on pavement research, placed an emphasis on collecting locally- or segment-specific vehicle loadings.  Some states have upgraded the WIM systems originally used only for data collection to contain screening capabilities, as found in virtual weigh stations, at relatively low cost.  Traffic monitoring functions have remained intact, while the addition of screening capabilities is attractive to the State’s enforcement agency and optimizes the utility of the WIM equipment.  If consideration is given to using existing WIM sites to support roadside enforcement, a State must be diligent in ensuring that an off-road location is available for enforcement officials to conduct more extensive weighing activities safely removed from the traffic stream should a roadside inspection be warranted.

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