摘要: |
Truck survey methods vary in the response rates they generate and in their coverage, accuracy, and cost. Roadside intercept/interview surveys enjoy representation, coverage, and response-rate advantages compared with phone/mail surveys, but in practice they are frequently restricted to weigh stations, toll plazas, and similar controlled facilities. A roadside truck interview survey for Berks County, Pennsylvania was conducted within the stream of traffic in conjunction with distribution of a postcard automobile survey. Over 1,000 interviews conducted throughout the county at five cordon locations representing key two-lane and four-lane roads were compiled. The sampling rate exceeded 22%, and valid response rates were approximately 98%. The information obtained was limited in detail but was sufficient to achieve the study objectives of estimating major internal-external, external-internal, and external-external truck movement patterns for Berks County. The study was not intended to identify internal-internal trips. The purpose, methodology, and advantages and disadvantages of the approach are discussed, and the focus is on the traffic congestion element. Surveys were conducted within a single lane in each direction, restricting traffic flows. At certain traffic volumes (roughly 200 vehicles per 15 min) delays became a significant problem, including several periods during which surveys were not conducted to alleviate traffic backups. The conclusion suggests using this parameter for applying the method to other locations. |