The results of the available data on the magnitude and distribution of commercial vehicle trips are presented in this report. There are quite a few data sources available to use to quantify these data and quite a few data gaps in trying to identify a comprehensive assessment of commercial vehicles in an urban area. These data gaps are discussed in Section 5.1. Some of the differences we identified potentially have to do with the definitions of categories rather than real differences in the amount of commercial vehicle travel. This problem could be alleviated, albeit not completely, by aggregating categories for analysis, as described in Section 4.2. Section 5.2 describes the results of an evaluation related to upcoming priorities for modeling in the next task in the project.
There are three categories of commercial vehicles where data could be obtained from only one source and for only a limited number of urban areas: Fixed Shuttle Service vehicles (category 2), Rental Cars (category 5), and Public Service vehicles (category 11). We had data on fixed shuttle service vehicles in 27 urban areas in the United States, but these included only included five of the cities we reviewed. The data were based on the Airport Ground Access Planning Guide, which is not an ongoing data collection effort but a one-time report designed to improve planning for airport ground access travel. Information on Rental Cars and Public Service vehicles were available only in the California Energy Commission database, which is DMV database that has been specially processed for use in California. The Polk data, a private sector source of DMV data, can be purchased to fill this data gap.
The urban areas with either DMV data or commercial vehicle survey data provide the most comprehensive evaluation of commercial vehicles in an urban area. In the commercial vehicle surveys, though, many trips made by what are defined for this project as commercial vehicles are excluded. This is apparent in the total percentage of vehicle miles traveled (VMT) and per capita fleet size statistics for an urban area because the areas for which the VMT are based on DMV data are quite a bit higher in total VMT than the cities for which the VMT are based on commercial vehicle survey data. These differences are readily apparent in categories where vehicles have been excluded, such as business and personal services, public service vehicles, public utility vehicles, public safety vehicles, and public mail delivery (U.S. Postal Service).
There also are gaps in the DMV databases because they include data only on fleet size, and the VIUS was used to estimate average miles per day for these data (since VMT data were not available in the DMV databases). The VIUS data can be used to estimate average miles per day for all urban areas in a state but not for individual urban areas because the sample sizes for individual areas are too small.
Table 5.1 presents the range of the percentage of VMT in the 11 urban areas in our evaluation (Houston and Orlando were not included as they did not have either registration or survey data sources). These 11 urban areas (presented in Table 4.6) were selected because the data were more comprehensive to support statistical evaluation. This table demonstrates that many of the commercial vehicle categories defined for this project have a negligible impact on VMT (school buses, fixed shuttle services, private transportation, and paratransit vehicles all comprise less than one percent of VMT). At a small-area level, however, the percentages may be significantly higher; for example, shuttle services may contribute a very high percentage of overall VMT near the airport, and taxis may contribute a very high percentage of overall VMT in downtown areas.
| Vehicle Type | Minimum | Maximum | Average |
|---|---|---|---|
| School Bus | 0.0% | 0.5% | 0.1% |
| Shuttle Service at Airports, Stations, etc. | 0.0% | 0.0% | 0.0% |
| Private Transportation: Taxi, Limos, Shuttles | 0.1% | 0.5% | 0.2% |
| Paratransit: Social Services, Church Buses | 0.0% | 0.0% | 0.0% |
| Rental Cars | 0.8% | 4.3% | 2.0% |
| Package, Product and Mail Delivery: USPS, UPS, FedEx, etc. | 0.0% | 0.7% | 0.2% |
| Urban Freight Distribution, Warehouse Deliveries | 1.0% | 4.9% | 2.7% |
| Construction Transport | 0.0% | 1.4% | 0.6% |
| Safety Vehicles: Police, Fire, Building Inspections, Tow Trucks | 0.1% | 1.3% | 0.4% |
| Utilities Vehicles: Trash, Meter Readers, Maintenance, Plumbers, Electricians, etc. | 0.0% | 1.0% | 0.3% |
| Public Service (Federal, State, City, Local Government) | 0.6% | 3.5% | 1.6% |
| Business and Personal Services (Personal Transportation, Realtors, Door-to-Door Sales, Public Relations) | 0.7% | 7.0% | 3.5% |
| TOTAL | 3.4% | 25.0% | 11.8% |
The commercial vehicles with the largest impact on vehicle miles traveled are Business and Personal Services (maximum 7.0 percent), Urban Freight Distribution (maximum 4.9 percent), Rental Cars (maximum 4.3 percent), and Public Service Vehicles (maximum 3.5 percent). The maximum values are used for this evaluation because the average across cities is affected by the exclusion of some vehicles in certain categories, making this statistic less useful for our purposes.
The overall impact of commercial vehicles ranges from 3.4 to 25.0 percent for the urban areas in our evaluation. This is reasonable compared to ballpark estimates of commercial vehicle travel in urban areas.
