Design vehicles were developed to evaluate the operation of low-ground-clearance, long-wheelbase, overhang vehicles on extreme hump or sag profile alignments. The literature review indicated that although formal studies had been conducted to develop design vehicles, these vehicles did not include the information needed to assess hang-up susceptibility on a particular vertical alignment. Relevant design vehicle dimensions for 17 vehicle types prone to hang-up were developed. Relevant dimensions included wheelbase, ground clearance, and front and rear overhang. These vehicles can be used in conjunction with the HANGUP software or other tools in designing vertical alignments that reduce the likelihood of hangup problems. Because they are based on representative samples of both field-collected and manufacturers' data and have been evaluated using the HANGUP software, the design vehicles are reasonable and have a rational basis. The proposed vehicles should receive broad review with an eye toward inclusion in appropriate design policies and guidelines.

Recent technological advances in computer hardware, software, and image processing have led to the development of an automated license plate reader (ALPR). This equipment was developed primarily for enforcement and security applications, such as monitoring parking garages or border crossings. Because license plate data are used in several transportation planning studies, ALPRs have the potential to increase the quality and efficiency of many typical activities of transportation planning agencies. The key performance attributes of an ALPR with respect to the specific needs of transportation planning are determined. The following general needs are investigated: ( a) the specific license plate data requirements of transportation planning studies; ( b) the effect of the equipment on traffic operations and safety; and ( c) special equipment characteristics required because of the temporary nature of transportation planning and the constraints of transportation planning agencies. In addition, an existing ALPR was tested in situations likely to be encountered in transportation planning applications. Technical specifications for an ALPR for transportation planning are developed. These specifications can be used to provide motivation and direction for the future development of an ALPR for transportation planning. Finally, the technical challenges to developing the ALPR are discussed.

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