U.S. Department of Transportation
Federal Highway Administration
1200 New Jersey Avenue, SE
Washington, DC 20590
Based on its general findings and observations, the scan team ranked a preliminary list of European commercial motor vehicle size and weight enforcement technologies and procedures as having "high," "medium," or "low" interest levels for implementation consideration in the United States. These relative rankings did not recommend implementation of the various technologies or procedures, but instead provided an indication of the interest in further investigation.
After the scan, the scan tour implementation team (STIT) focused on implementation opportunities assigned a high interest level and worked further with scan team members to prioritize the 17 initial opportunities included in this category. Some opportunities were later combined because of perceived overlap. Through this process, the STIT identified seven specific implementation opportunities as having the greatest potential benefit to U.S. commercial motor vehicle size and weight enforcement procedures:
Specific strategies for advancing these implementation opportunities were also identified, with various scan team members assigned supporting action items. These implementation opportunities and strategies are detailed below.
B-WIM was initially identified in the late 1970s in the United States and developed in the WAVE Project. European researchers continued to advance field testing and applied research of the concept, leading to its widespread deployment in Slovenia. B-WIM is a vital component of Slovenia's commercial motor vehicle weight monitoring system and is used to prescreen commercial vehicles for weight enforcement purposes. SiWIM in Slovenia was developed and implemented through a partnership between staff at the National Building and Civil Engineering Institute's (ZAG) Research Department and a private engineering firm, CESTEL. Deployment of Slovenian SiWIM targets short-deck (5- to 10-meter) orthotropic bridges. Extensive research into the bridge deck's reaction to weights has led to the ability to estimate, within acceptable levels of accuracy for prescreening, a vehicle's static weight. Analysis and data collection leading to this capability centered on the behavior of the "influence line" when truck weights are applied to the bridge's deck. Weight-detection instrumentation is applied at the under-deck location of the structure, eliminating the need to disrupt traffic flow during installation. Multiple sensors are used to monitor travel lanes, and a sensor data hub or cabinet feature draws readings from the individual sensors and generates a composite of the deck loading readings. Axle weights, gross vehicle weights, axle spacing, vehicle speed, and vehicle class are captured through this data collection approach.
The Netherlands is analyzing its inventory of structures to determine the number and location of bridges where B-WIM could be deployed. Recently, one bridge WIM system was installed for testing under Dutch highway conditions. In France, significant applied research efforts are concentrated on advancing the use of B-WIM on multiple-span, multiple-lane structures and steel orthotropic deck bridges. The target of research is the filtering of sensor readings from several vehicles on the bridge deck simultaneously. The scan team visited the Autreville orthotropic steel bridge site on the A31 motorway outside of Nancy, France. French hosts provided a tour of the site layout and demonstrated the SiWIM under testing.
Because it eliminates the need to disrupt traffic flow and minimizes the worker risk involved in installing traditional roadway telemetry, B-WIM was seen to possess major benefits over U.S. practices. Also, as seen in Slovenia, the time required for installation is not significant and, once bridge deck superstructures are instrumented, BWIM is highly portable. In Slovenia, five SiWIM devices are used to collect data for 1 week at 30 locations twice a year. Applications of B-WIM in the United States would enhance prescreening capabilities for commercial motor vehicle weight enforcement, as well as provide important information to bridge management systems. The choice of a suitable bridge and the development of an appropriate instrumentation plan and related calibration procedures may be challenging and require a high expertise level.
In an effort to protect highway tunnel facilities and roadway infrastructure from the impacts of heavy trucks, Switzerland has developed and implemented an efficient and effective approach to simultaneously measuring commercial vehicle size and weight at stationary enforcement locations. The system also includes a high-speed WIM (HS-WIM) and video (VID) technology component used to prescreen strategically selected trucks requiring additional measurements.
The scan team had the opportunity to observe enforcement procedures at the control facility outside of Bern, Switzerland. Mobile enforcement details escorted vehicles into the facility for additional measurements using the HS-WIM/VID prescreening capability. Vehicles were directed onto a weigh bridge (i.e., static scale pad instrumented with several load cell scales) that provided simultaneous axle and gross vehicle weight measurements. An overhead gantry fitted with laser scanners capable of capturing commercial vehicle length, height, and width measurements is used simultaneously.
An attractive element of the Swiss heavy goods control facility operation is the user-friendly presentation of data to enforcement officers operating the system. A horizontal line on the computer screen represents legal axle and gross vehicle weight allowances with violations clearly shown as exceeding this allowance line. Size dimensions exceeding legal allowances are highlighted in red on a three-dimensional model of the vehicle. Size- and weight-related citations are generated automatically for issuance to the vehicle operator and submission to the appropriate judiciary officials. Swiss enforcement personnel described the advantages of this system over the traditional portable scale and manual measurements efforts. More accurate measurements are achieved with less manpower, resulting in more effective enforcement in considerably less time. The Swiss operate three control centers, with additional centers in the planning and development stages. The scan team believes that U.S. deployment of such an enforcement station at key high-volume domestic or international land-crossing locations would be beneficial.
A significant level of interest exists in the United States in the use of automation tools and technology to improve the conduct of commercial motor vehicle size and weight enforcement. The scan team witnessed similar mobile enforcement activities in four of the six countries visited: Slovenia, Switzerland, the Netherlands, and France. Common features and elements were identified in each. High-speed WIM technology was used in each case for mainline prescreening of suspected overweight commercial motor vehicles. Video capture (i.e., digital photo images) of the vehicle was triggered by overweight detections. Both weight and image data were transmitted via short-range communications to enforcement personnel, allowing them to identify appropriate commercial vehicles in the traffic stream and escort them off of the mainline for further investigation. Such systems are referred to as WIM/VID in Europe. Such approaches were embraced by the COST 323 action and are used widely by EU member nations.
U.S. States use elements of this approach to varying degrees. The scan team identified the need for a comparative analysis to measure the differences between the state of the practice for mobile enforcement in the United States and that observed in European countries. The team believes that advancement of the most effective mobile enforcement practices could be supported and delivered most expeditiously once State-level variations are identified and compared to practices used in Europe.
In many cases, the difficulty in deploying advanced technologies stems from institutional barriers. The widespread deployment and use of technologies for commercial motor vehicle size and weight enforcement require support from both the metrological bodies responsible for equipment certification and judicial bodies responsible for related legal actions. Low-speed WIM systems can be tested and certified using similar methods as static weighing equipment, making their use a logical first step toward direct enforcement. The testing and certification process for high-speed WIM systems is more complex and requires the development of new acceptance methods.
French officials are leading the effort to overcome institutional challenges to the use of low-speed WIM systems for direct enforcement (i.e., gaining acceptance from the national metrology and judiciary communities). While the French are focused on the initial acceptance of low-speed WIM systems for direct enforcement, the Dutch are focused on gaining acceptance of high-speed WIM for direct enforcement.
Because a similar development process would be required in the United States, the scan team recommended an indepth review of the French and Dutch evolutionary process for acceptance of WIM systems for direct enforcement, with a concurrent review of the U.S. direct enforcement climate and requirements.
Using the European WIM/VID (photo) approach of simultaneously capturing a digital image of the vehicle when an overweight condition is detected, officials in the Netherlands and France have gained additional knowledge of the trucking firms most frequently operating in an overweight condition. This information is captured continuously (i.e., 24 hours a day, 7 days a week), regardless of whether a mobile enforcement activity is taking place. Historical WIM information is reviewed, typically on a monthly basis, to determine trucking firms that most frequently engage in overloading practices. Enforcement officials contact the most frequently offending firms to encourage compliant loading behavior. Following this contact, the trucking firm then begins a probationary period. If no positive change is observed through continued monitoring by the WIM/VID systems, graduated enforcement actions are taken. France is just beginning a 3-year study to determine the effectiveness of this process.
The scan team observed that this general process is similar to the safety inspection steps routinely followed by the Federal Motor Carrier Safety Administration (FMCSA) in its oversight of trucking firms operating commercial vehicle fleets. The application of this process to commercial motor vehicle weight enforcement in the United States shows promise for firms that could have reasonably brought their loading practices into legal compliance with relevant laws.
In the United States, justification and authority for the conduct of commercial vehicle weight enforcement are vested in the public's interest in preserving highway infrastructure and promoting a climate of equity and fairness among trucking firms (e.g., not allowing violators to be rewarded at the expense of law-abiding firms). These same principles and interests were reported in each of the European countries the scan team visited. In addition, several countries visited identified safety as a primary motivator for commercial vehicle size and weight enforcement. In Belgium, officials have linked weight enforcement activities to the public's interest in safe operating conditions on the highways. After years of weight and speed data collection and analysis, Belgium officials noted direct relationships between excessive speed by overweight vehicles involved in highway accidents and the frequency of fatalities occurring in accidents including such vehicles. As such, they were able to build the case to their legislative leaders that weight and speed needed to be aggressively regulated. To control speed, governors, or speed-monitoring devices, are installed on trucks to control their maximum speed. Speed violations are treated as criminal offenses because excessive speeds can be achieved only as a result of tampering with the speed-control devices.
The scan team indicated a desire to better understand the relationship between commercial motor vehicle weight condition and safety in the United States. While public concerns about overweight vehicles impacting bridge and pavement conditions and undermining equitable trade practices are valid, the safety benefits tied to commercial vehicle weight enforcement activities need to be better defined. The scan team proposes that an assimilation of existing safety studies and research be undertaken to improve understanding.
In the Netherlands, every Wednesday morning at 7 a.m., an e-mail with an attachment detailing the frequency of truck weight violations by location, time of day, and day of the week is distributed to enforcement personnel responsible for scheduling enforcement actions and transportation personnel charged with infrastructure condition monitoring and multimodal freight planning and forecasting. The data report is a product of an extensive database management operation constructed by Dutch officials. Extensive quality control and quality assurance protocols have been built into the operation of this data management system.
In the United States, State-level officials operate data management systems to manage their highway and bridge programs and to monitor travel to support program and policy development. The scan team determined that documentation of the Dutch database management system could assist States in extracting greater value from the database systems in operation.
Next steps include defining specific timeframes and funding requirements for implementation. Once defined, specific funding sources can be identified and secured.
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