Ensure that new technology deployed in a weigh station to detect high-risk heavy trucks is in alignment with state organizational goals and inspection priorities.
Evaluation of an Integrated Safety and Security Enforcement System (ISSES) in a weigh station on I-75 in Kentucky installed to detect high-risk heavy trucks
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United States

Kentucky Commercial Vehicle Safety Applications Evaluation: Technical Report


In 2005 the State of Kentucky, in partnership with the U.S. DOT, installed a system of technologies for the detection of high-risk heavy trucks at a weigh/inspection station on I-75 near London, Kentucky. The system, referred to as an Integrated Safety and Security Enforcement System (ISSES), was deployed to support Kentucky Vehicle Enforcement (KVE) by automatically accessing safety information from heavy trucks as they passed the scale house in the inspection station. The ISSES included a U.S. DOT number reader, an automated license plate recognition system (ALPR) and a laser-based system for classifying vehicles (e.g., based on the number of axles). The ISSES also had a detection system for bulk radiation and a thermal imaging inspection system to identify threats to homeland security.

Lessons Learned

An evaluation of the ISSES installed at the weigh/inspection station on I-75 near London, Kentucky found that the ISSES subsystems functioned according to performance specifications but that in general, the ISSES did not appear to have improved inspection efficiency (i.e., selecting vehicles for inspection that are more likely to have a violation). The evaluation revealed key lessons learned in the design and deployment of new technology that should be considered when planning for an ISSES or similar inspection decision-aid system, as follows:

  • Deploy an ISSES with a purpose and function that aligns with state enforcement goals and inspection priorities. The Kentucky state inspection process emphasized the quantity of completed inspections, whereas the purpose of the ISSES was to increase the rate of Out of Service (OOS) orders issued. Each of these goals is valid but involves different procedures and priorities. The functions built into the ISSES were designed to help inspectors focus on the trucks with the worst safety records, an outcome which did not directly support the organizational goal of achieving a certain number of inspections performed.
  • Ensure that the weigh station has adequate staffing levels for inspectors to have the time and resources to use an ISSES. The staffing levels at the weigh station may have been a barrier to inspectors integrating the ISSES with their day-to-day tasks. In fact, the inspectors followed through on the standard screening activities while not in general attending to the information displayed on the ISSES display screens. Inspectors tended to rely on their visual judgment and knowledge of the carriers to select trucks for inspection. Inspector feedback suggests that inspectors considered scanning the ISSES screen for information as generally not a productive use of time.
  • Provide adequate training on the ISSES so that inspectors understand how to read and interpret the ISSES displays. The evaluation revealed that most inspectors did not believe that they had received adequate training on the ISSES, even though training was provided to some extent. In addition, the level of on-site support for the ISSES appears to have been too low to have helped staff with questions and/or troubleshooting.
    • Make clear how the ISSES can augment the current inspection process in ISSES training. It should be made clear to inspectors how the ISSES will support current inspection practices and inspection priorities, tasks and organizational goals. Training should include important details such as how to read the radiation monitor while interpreting a truck profile, understanding the meaning of radiation dose rate values and interpreting the thermal imaging equipment to recognize brake violations.
    • Provide refresher training. Inspectors responding to user acceptance questions indicated that they were not familiar with the ISSES equipment. Conducting follow-up assessments on training effectiveness would help ensure that inspectors know how to use the ISSES. Providing ISSES user guides and contact information on-site is also valuable.
  • Upon deployment, integrate the ISSES with inspection, registration, licensing and safety databases so that it provides immediate value to the weigh/inspection station. At the Interstate 75 weigh/inspection station, the ISSES had not yet been integrated with state or federal safety information systems. As a result, information on the truck passing through ISSES equipment (e.g., the bulk radiation detection monitor, thermal imaging inspection system, vehicle classification system, U.S. DOT number reader, and license plate recognition system) was not integrated with Kentucky or federal safety data sources. Therefore, inspectors in general did not use ISSES information in their inspection selection decision.
  • Consider the potential costs as well as the advantages of using off-the-shelf technology. Commercially available, off-the-shelf software may have initial lower costs than custom software, but can be costly in the long run due to the challenges of integrating different hardware and software systems. The evaluation found significant costs associated with the operational problems associated with integrating off-the-shelf technology.
  • Design and install the ISSES so that it performs as planned in the field. Physical constraints in the field will affect the capabilities and performance of the ISSES. For example, trucks may drive through ISSES equipment at higher speeds than the posted speed limit (which is frequently 10 MPH on the ramp) or outside of the range of the equipment. Check that the design parameters while installing the technology to ensure that it can function as planned. For example:
    • Build the Optical Character Recognition (OCR) system so that it will detect characters from trucks at the speeds with which they are likely to drive by the ISSES equipment. The OCR system on the ISSES was designed for trucks traveling 15 MPH by the equipment, but trucks routinely traveled up to 20 or 30 MPH. Similarly, the capability of the ISSES to identify trace radiation sources is weakened when vehicles travel faster than the design speed of 15 MPH. (There is a balancing act between moving trucks quickly through the station and slowing them down enough for automated systems to capture data.)
    • Position radiation monitors high enough to target the majority of a vehicle’s cargo area. In weigh stations in Kenton and Simpson County, Kentucky, radiation detection panels were positioned so close to the ground that they missed the majority of a vehicle’s cargo area. Elevating the panels or adding additional ones is a significant cost. Also, the evaluation found that the gamma alarm gave off frequent nuisance alarms because it became activated in the presence of naturally occurring but harmless material (e.g., bricks) that emit gamma rays. The effect was that inspection staff tended to ignore the alarms.
    • Involve inspectors in the decision to locate the ISSES. Inspectors noted that the ISSES was very close to the scale house, leaving little time for inspectors to read and interpret results displayed by the ISSES before the trucks had moved on.

The ISSES is designed to increase safety by automatically identifying trucks that are likely to have Out of Service (OOS) violations and thereby reducing the probability of these trucks being involved in a crash. The benefits of using an ISSES in a weigh station will be realized when it is integrated into existing safety databases and if it supports the priorities and procedures of the inspection staff.

Kentucky Commercial Vehicle Safety Applications Evaluation: Technical Report

Kentucky Commercial Vehicle Safety Applications Evaluation: Technical Report
Publication Sort Date
V.J. Brown, M.S. Anderson, R.N. Sell, J.A. Zewatsky, J.E. Orban
U.S. Department of Transportation
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