I TruckAccident Countermeasures for Urban Freeways

The issue of truck accidents on urban freeways is a vital concern for both traffic managers and the general public. The passage of the Surface Transportation Assistance Act of 1982 and recently the North American Free Trade Agreement has increased the numbers of large combination vehicles on the highway system. The rise in truck volume (defined as vehicles exceeding 4.5 Mg (10,000 lbs), the interaction of these large vehicles with other traffic, and the publicity given to major truck accidents have focused public awareness on the consequences of truck accidents and incidents. In urban environments, trucks are being required to maneuver in denser traffic streams. For example, truck accidents in California have increased by 10 percent per year since 1985, when their total number was 12,000. Delays averaging 2,500 vehicle-hours have been noted for each accident in California.’ A study by Bowman and Hummer estimated the annual cost of high-volume urban freeway truck accidents at $634,000 per freeway mile.’ In a recent Federal Highway Administration (FHWA) project, a literature review, telephone interviews with representatives from selected operating agencies, and visits to selected sites identified countermeasures used to reduce truck accidents on urban freeways. Researchers were to collect no field data, relying instead on data and information that was readily available from operating agencies responsible for countermeasure implementation, In many cases, agency personnel believed countermeasures to have been effective, but due to resource limitations none included a comprehensive evaluation, as in a “before-and-after” study. Truck accident countermeasures investigated in this study included those related to roadway design and operations; countermeasures directly related to the vehicle and driver were excluded. Of the 11 countermeasures initially identified and described in Table 1, the first seven were targeted for closer scrutiny. Selecting the countermeasures began with a literature review and a survey of FHWA field offices to determine where countermeasures had been implemented. The initial contact to the responsible agency determined the person who was most knowledgeable for subsequent interview. Criteria used to select targeted countermeasures were accident reduction capability, data or information availability, and regional representation. Reports developed from this research include detailed case studies and an annotated bibliography.34