The collection of classified vehicle counts in an urban area: accuracy issues and results.

To produce estimates of small area commercial vehicle trips, Transport Data Centre developed a commercial vehicle trip estimation procedure that utilises three major data inputs: trip ends, screenline counts and a prior matrix from a previous large-scale Commercial Vehicle Survey. One known weakness of the current CTS 1996 base year estimates is that the heavy vehicle screenlines were derived mainly using assumed proportions of rigid and articulated trucks from annual average daily traffic (AADT) counts. This is due to the lack of actual classified counts on major freight routes because of the difficulty in obtaining accurate counts on roads characterised by high traffic volume, multiple lanes and heavy congestion. To address this problem, TDC conducted a comprehensive Classified Vehicle Count Study in 2002. (Author/publisher) For the covering entry of this conference, please see ITRD abstract no. E210413.