In October, 2003, the Federal Highway Administration began a research project to evaluate the magnitude and distribution of commercial vehicles in urban transportation planning models. The research was designed to look at all travel that is not adequately represented by the current state of the practice for urban transportation planning models, which are developed from household travel surveys. Household travel surveys are designed only to capture household-related personal travel. Trips made for commercial purposes or using commercial vehicles are not captured. Some household travel surveys may inadvertently capture commercial trips such as realtors or tradesman making door-to-door visits but this does not represent a comprehensive assessment of this type of commercial vehicle travel.
This project is the first phase of a two-phase project to develop methods for forecasting commercial vehicles in urban transportation planning models. The goal of the first phase is to research, evaluate and identify methods for forecasting commercial vehicles in urban transportation planning models. The goal of the second phase is to develop these methods and estimate parameters that can be used in urban transportation planning models across the country.
The first phase has three primary work tasks:
The focus of this report is on the second work task to estimate the magnitude and spatial and temporal distribution of different types of commercial vehicles.
As part of this work, we defined a commercial vehicle as one that is used primarily for commercial purposes. Many commercial vehicles will be registered as commercial vehicles. Commercial vehicles include autos, trucks and buses and are operated by both public and private sector agencies.
Trips made by commercial vehicles are organized in three groups, based on what is being carried and what economic, demographic and land use factors influence the magnitude and distribution of these trips. The three groups are commercial vehicles: moving people, moving goods and providing services.
These three groups are further subdivided into 12 specific categories of commercial vehicles, based again on what is being carried and what economic, demographic and land use factors influence the magnitude and distribution of these trips. These 12 categories of commercial vehicles are:
These 12 categories of commercial vehicles are direct subsets of the three commercial vehicle groups, as follows: school bus, shuttle services, taxis, paratransit and rental cars are vehicles moving people; package delivery, urban freight distribution and construction transport are vehicles moving goods; and safety, utility and public service vehicles and business and personal services are vehicles providing services.
One additional category of commercial vehicles is public and private buses. These vehicles were not evaluated in this study because some metropolitan transportation agencies are already modeling public and private buses as part of the multimodal demand forecasting process. These would be modeled as part of the development of the transit network; bus vehicle miles traveled can be estimated from the bus services coded in the transit network. Private buses are not as frequently modeled in urban transportation planning models, because they are primarily intercity trips and would be modeled using an intercity or statewide model.
The effort to quantify the magnitude and distribution of commercial vehicle travel relied on a series of data sources that provided data on vehicles, trips, trip lengths and/or vehicle miles traveled in each of 12 commercial vehicle categories. Based on these data, commercial vehicle travel was estimated for 13 urban areas in the U.S. Most of the data sources provided data for multiple categories of commercial vehicles (such as the registration data and the commercial vehicle surveys) but some data sources were category-specific (such as the school bus fleet data, the taxi fact book, the FTA Section 15 data on transit. The primary data sources and the urban areas available in each are provided below:
There were many other data sources reviewed and used to support the estimation of the magnitude and distribution of commercial vehicles. One significant contributor was the Vehicle Inventory and Use Survey (VIUS), which was used to estimate average miles traveled per day for the 12 vehicle categories in our study, but these data were not specific to an urban area only to all urban areas in a state.
The magnitude and distribution of commercial vehicles in each of 12 commercial vehicle categories were estimated from available data sources. The magnitude was estimated using the total fleet size and fleet size per capita. The distribution was estimated using the vehicle miles traveled, the percentage of total vehicle miles traveled and the average vehicle miles traveled per day.
The magnitude of commercial vehicles ranged from two to 89 fleet size per thousand population for all categories. This was highest for vehicles providing services, based on the fleet size per capita rates across all 13 urban areas (average of 26 vehicles per thousand population). While we feel that average among groups of commercial vehicles are reasonable to report for comparison, the maximum statistics are used to evaluate individual categories because of the missing data in many cities. Among the specific categories within the services group, business and personal service vehicles (38 vehicles per thousand population) and public service vehicles (26 vehicles per thousand population) had the highest rates. Urban freight vehicles (35 vehicles per thousand population) and rental cars (22 vehicles per thousand population) also had a high average rates of fleet size per capita. Package delivery (13 vehicles per thousand population) had a lower maximum fleet size per capita rate and all other categories had less than 10 vehicles per thousand population maximum fleet sizes.
Distribution of commercial vehicles ranged from seven to 18 percent of total vehicle miles traveled, across all categories. This was highest for vehicles providing services (five percent), based on the percent of total vehicle miles traveled. Again, the maximum percent of total vehicle miles traveled was used to evaluate the individual categories. Urban freight distribution and business and personal services (both at eight percent) had the highest percent of total vehicle miles traveled, next highest was rental cars (four percent) and public service vehicles (three percent). All other categories had less than two percent of total vehicle miles traveled (maximum).
The magnitude and distribution was also evaluated across time periods and facility types, but these data were not sufficient to stratify the data by urban area or commercial vehicle category. Based on data from the commercial vehicle surveys, the majority of commercial vehicles operate in the off-peak hours (58 percent). The a.m. peak period of three hours (31 percent) has quite a bit more travel than the p.m. peak period of three hours (11 percent). The distribution of commercial vehicles by facility type is based on data in the Freight Analysis Framework. This shows that freight and non-freight trucks have higher allocation of vehicle miles traveled on interstates and lower allocation of vehicle miles traveled on arterials than autos.
The analysis of the magnitude and distribution of commercial vehicle travel uncovered a number of gaps in the data that made comparison of data across categories of vehicles and across different urban areas more challenging. The most comprehensive data sources were the department of motor vehicles data, which included all vehicle types but did not contain any data on miles traveled, and the commercial vehicle survey data, which included all data necessary for the analysis, but did not include all vehicle types. There was limited data on shuttle services, rental cars and public service vehicles. These data gaps will be identified as areas for future research in the next task of the work.
The overall impact of commercial vehicles ranges from six to 18 percent vehicle miles traveled for the urban areas in our evaluation. This is reasonable compared to ballpark estimates of commercial vehicle travel in urban areas. The next step in the overall evaluation is to identify methods, parameters and data sources that can be used to estimate and forecast commercial vehicles in urban transportation planning models. The data sources contained herein will be used as a basis for this evaluation, combined with additional data sources needed for forecasting purposes.
