Title: Impact of Posted Speed Limits on Operating Speed in Urban Expressways
Abstract: The relationship between posted speed limits and operating speed is one of the main factors in determining appropriate speed limits in a speed zone. In this research, 19 sites were randomly selected from the 3rd, 4th, and 5th Express Ring-Road in Beijing, and the spot speed and headway data were collected at these sites. Then, free-speed data were reduced from the original data, and the 85th percentile speeds were computed as each site's operating speed. Deviation analysis of operating speed at the 3rd and 4th site shows that there were no obvious distinctions between these two types of road facilities. The regression analysis of posted speed limits and operating speed shows that there exists a strong linear relationship between these two speed terms. The percentage of operating speed exceeding posted speed limits increases with the speed limit value. The relationships between speed limits and operating speed established here may be expected to provide some quantifying basis for transportation agencies to set posted speed limits in speed zones. Results of this study may help the Department of Transportation and its districts quantify the speed limits and provide more objective insights for setting speed limits.
Publication Year: 2009
Publication Date: 2009-07-23
Language: en
Type: article
Indexed In: ['crossref']
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