Citation

Hallenbeck M. Transp. Res. Rec. 1993; 1397: 63-67.

Copyright

(Copyright © 1993, Transportation Research Board, National Research Council, National Academy of Sciences USA, Publisher SAGE Publishing)

DOI

unavailable

PMID

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Abstract

For many years states have collected year-round traffic volume information at specific sites in order to measure traffic patterns as they change throughout the year. Because of a lack of data that showed otherwise, it was assumed that all vehicle types had seasonal patterns that were similar to those observed for total traffic. In the 1980s advances in computer and sensor technology allowed states to expand this traditional data collection process to include volumes by vehicle classification and truck weights. The preliminary results of an analysis of the seasonal volume patterns for different vehicle classes in the state of Washington are presented. In Washington trucks have very different travel patterns from automobiles. In addition, the various truck types often have different seasonal patterns. The factors that are needed to convert 24- or 48-hr weekday vehicle classification counts to average annual daily estimates of truck volumes by classification vary from truck type to truck type and from site to site. As might be expected, higher-volume roads have more stable seasonal patterns. Lower-volume roads show greater variability from month to month and from year to year. The stability of seasonal patterns is also affected by the volume of vehicles within specific vehicle classes. In general, the greater the volume within a specific vehicle class, the more stable that pattern is from year to year. The lower the volume in a particular class, the less stable is that pattern. Examples of the common types of truck volume patterns are shown, the effects of two vehicle classification schemes on the patterns observed are described, and the implications of those patterns on geometric and pavement design are discussed briefly.

Record URL:
http://onlinepubs.trb.org/Onlinepubs/trr/1993/1397/1397-009.pdf

Language: en