Proposal Summary

This proposal defines a work plan for the California Vehicle Inventory and Use Survey (CA-VIUS), which will focus on freight related vehicles operating in California, with questions designed to obtain annual freight truck activities, operational characteristics, physical characteristics, and the types of commodities carried at the state level. The survey results are needed for the development and validation of the Emissions Factors (EMFAC) model for the California Air Resources Board (CARB), since its assumptions for base and target years are based on VIUS data including vehicle miles traveled (VMT), and commodity and truck fleet characteristics. The survey results are also expected to yield key insights on the inventory and flow of different types of commodities and truck fleets that are critical for statewide freight travel demand modeling as well as forecasting transportation energy demand by the California Department of Transportation (Caltrans) and the California Energy Commission (CEC). Following the discontinuation of the VIUS at the national level by the U.S. Census Bureau in 2002, it has become a challenge to obtain equivalent data for satisfying the aforementioned needs. Thus, this first phase of the CA-VIUS study is proposed to build an appropriate survey framework as well as to implement a pilot survey in California in an effort to provide the necessary update of freight movement data for the State of California.

The final deliverables of this project will include the following: the proposed survey sample design with associated supporting methodology and data analysis, digitized pilot survey data with completed survey response sheets, statistical analysis of pilot survey results, freight related factors generated from pilot survey results, and a final report including a comprehensive survey framework, procedure, pilot survey implementation issues, and the corresponding responses to pilot survey implementation issues. While the pilot survey will only cover a selected sub-region of California based on the developed comprehensive survey framework, the pilot survey is expected to provide guidelines and be combined with later surveys applicable to the entire state of California, including the sub-region of the pilot survey.

The tasks defined for this project are split into three main phases: the first involves survey design and preparation, the second encompasses conducting the pilot survey, while the final phase involves presenting and analyzing survey results. The survey design and preparation phases consist of tasks including literature review, background information collection, decisions for sampling frame, sample size determination, sample selection procedures, survey questionnaire design and survey method selection. To the best of our knowledge, the population of trucks operating in California, regardless of the state in which the trucks are registered, can be obtained both from the California Department of Motor Vehicles (DMV) and the International Registration Plan (IRP), and these sources will be used for sampling framework decisions. Based on initial analysis, a mail-out and mail-back survey design for instate and interstate trucks is likely to be recommended. The design of survey questions will also involve reviewing the 2002 VIUS questionnaire to ensure consistency between them. The tasks for conducting the survey will depend on the anticipated response rate as well as the reliability of the response results. In order to address the possibility of low response rate and to improve survey results, a pilot survey will be prepared and telephone and e-mail services for answering the respondents' questions regarding the survey will be adopted. The tasks associated with the final phase are the analysis of pilot survey results and generation of useful freight-related factors for stakeholders.