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39 State Department of Transportation, and Portland Metro (the In 19992001, the National Roadside Survey (NRS) was region's MPO). Roadside intercept surveys were conducted conducted across Canada. This nationwide truck survey at nine external gateways (highways) to the region, rest areas, comprised the aforementioned Ontario survey, as well as weigh stations, and truck inspection locations. Truck counts surveys in other provinces and at U.S. border crossings. A were conducted in order to allow for expansion of the data. selection of intermodal terminals also was surveyed. The NRS was a cooperative effort among the federal and pro- vincial ministries of transportation as well as the FHWA (with respect to the border crossings). Approximately 65,000 trucks were surveyed at 238 data collection sites. The NRS provides a proven example of a nationwide pro- gram for collecting inter-urban truck traffic, one that could be followed in the United States. A consistent survey form, a common general surveying procedure, and common classifi- cations and terms were developed and used across the coun- try. However, although driver interviews were conducted by local staff who were familiar with local travel and vehicle characteristics, some variations in the data collection were observed. Different groups having different objectives (e.g., enforcement, planning, and policy development) gathered the data. This reflected each province's interest in participat- ing in the NRS. However, as a result of these different inter- ests, there was some variation in the focus of the interviews: some focused on vehicle weight and dimensions, which are FIGURE 2 PDA questions--Georgia DOT. [Source : important for enforcement, and others focused on trip details, Statewide Truck Lanes Needs Identification Study, Technical which are important for planning. Although these differ- Memorandum 1: Data Collection (4).] ences must be captured, local nuances must be captured in a "well-planned and consistent manner when national data The surveys collected data on truck type, cargo type, for a wide range of uses are collected" (10 ). A further com- cargo weight, trip origin and destination, facility type at ori- plication arose in the expansion of the 19992000 NRS data, gin and destination, location of the truck's home base, activ- whereby the provinces of Ontario and Qubec and the fed- ity at the origin and destination (i.e., pick up, delivery, or eral ministry of transportation each used a different method. return to base), carrier type, and whether the vehicle had a This means that the resultant travel characteristics and trip WIM transponder. The survey also asked about the highways tables may differ for the same location, depending on whose used during the sampled trip, including the interchanges and expansion method is used. access roads between the highways and the origin and desti- nation (5, 6 ). Figure 3 shows the survey form. Figure 4 shows Data from a 20052007 update to the NRS currently are a variation of the form that was used for roadside interviews being analyzed. Although direct data entry has been in place at entrances to key freight terminals in the region. The form since the 1995 survey, this survey incorporated a GIS-based was administered to drivers at marine and rail terminals, routing component that enabled the surveyor to confirm the tank farms, and pipeline terminals. route with the driver and, if necessary, to modify it in order to get an accurate profile of the highways used for the trip. Commercial Vehicle Survey--Ontario, Canada The 19992001 NRS asked drivers to list the highways used in the trip: this information was used to confirm the route The Ministry of Transportation of Ontario, Canada, has during the data processing stage (11). conducted a large-scale truck roadside origin-destination survey at approximately 5-year intervals since 1978. The surveys are conducted on provincial highways and at inspec- ROADSIDE/INTERCEPT SURVEYS--SPECIFIC TOPICS tion stations, rest stops, and interprovincial and international (U.S.) border crossings. They focus on inter-urban trips. The It is important to note that some roadside/intercept surveys, surveys have collected information on carrier information; although following the general format of the aforementioned vehicle type, number of axles, and weight; trip origin and surveys, focus on specific geographical areas and issues. destination; and commodity type and value (9). The survey As a result, the types of questions may vary from the gen- focuses on heavy trucks, so other commercial vehicles are eral format, with greater or lesser focus on specific types not captured. Intraurban travel also is not captured. of data.

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40 FIGURE 3 Roadside Intercept Truck Survey Form--Portland region. [Source : Roadside Intercept Survey (7) .] For example, some studies have examined drayage activity streets and freeways that were used for the trip. Traffic counts at marine ports. Drayage refers to local movements between a were collected at the same time. Approximately 10,000 surveys port and its surrounding urban area (i.e., local transportation were distributed, and 3,300 of these (33%) were returned (13). within the urban area). Because the dray trucks operate primar- A 2008 study of drayage at the Port of Houston gathered similar ily in an urban environment, they can have a significant impact information to the aforementioned survey, but also asked about on congestion and air quality (12). A 2001 study surveyed truck trip distance (average length of drayage haul), the frequency of drivers entering and exiting the Port of Los Angeles/Port of trips on a typical day, location of "worst traffic" along the route, Long Beach. The survey solicited information about the truck cause of delay, use of a toll facility, average wait time (idle time) type, the type of origin or destination (off-dock, intermodal entering the Port (Barbours Cut Terminal), and the actual wait facility, industrial facility or warehouse, another port terminal, time for the current trip. Demographic information and vehicle other), the location of the origin or destination, and the specific characteristics (age and total mileage) also were gathered (12).