Traffic data exhibits considerable variability, both spatially and temporally. Given limited resources and the large geographic coverage required for data collection efforts, short period (24-hours to 7-day) traffic data collection must often serve to represent average conditions. Yet, in order for short period traffic counts to most accurately reflect annual average daily traffic (AADT) estimates, for instance, we must apply factors to take into account temporal variation, particularly seasonal (monthly) and day-of-week variation. To narrow the scope of the study, this paper will focus solely on total volume count data. Sharpening the focus further, the paper will deal with practical approaches to handling one of the largest sources of temporal variation in traffic data - seasonal variation. The techniques presented, however, have broader applicability to other sources of variation in traffic data. The paper will attempt to show how a combination of approaches - using statistical measures such as the coefficient of variation, statistical procedures such as cluster analysis, plots of monthly traffic factors, and geographical mapping of continuous count sites - can produce seasonal factor groups and seasonal adjustment factors to substantially account for seasonal variation and thus produce more accurate AADT estimates for end uses. 14 p.
The Illinois Department of Transportation (IDOT) has requested a waiver from the Federal Highway Administration (FHWA) toallow IDOT to implement a 24-...
For this validation study, NREL compiled traffic volume data from permanent traffic counters at over 500 locations across the U.S. These data were use...
Links with this icon indicate that you are leaving a Bureau of Transportation
Statistics (BTS)/National Transportation Library (NTL)
Web-based service.
Thank you for visiting.
You are about to access a non-government link outside of
the U.S. Department of Transportation's National
Transportation Library.
Please note: While links to Web sites outside of DOT are
offered for your convenience, when you exit DOT Web sites,
Federal privacy policy and Section 508 of the Rehabilitation
Act (accessibility requirements) no longer apply. In
addition, DOT does not attest to the accuracy, relevance,
timeliness or completeness of information provided by linked
sites. Linking to a Web site does not constitute an
endorsement by DOT of the sponsors of the site or the
products presented on the site. For more information, please
view DOT's Web site linking policy.
To get back to the page you were previously viewing, click
your Cancel button.
United States Department of Transportation
[PDF-167.58 KB]
