The Use of Three Surveys for Long Distance Travel Estimates in California

Information on long distance travel is crucial for interregional and statewide travel forecasting. While long distance trips may account for a small percentage of total trips within a state, they produce an inordinate share of the statewide vehicle-miles of travel (VMT). For example, based on the daily diary information from the recent California Statewide Household Travel Survey (CSHTS), trips to locations more than 50 miles from travelers’ residences comprised about two percent of the total daily trip making, yet produced about 30 percent of the statewide VMT. While typical, one-day travel diaries can provide some useful information regarding long distance travel, they are an inefficient source of information for the detailed analysis of long distance travel. Since long distance travel is a relatively rare occurrence for most households–the average person makes approximately nine long distance round trips per year–most household will not report any long distance travel in a survey collecting travel data for a single travel day. In fact, only five percent of households participating in the CSHTS reported any long distance trips in their daily diaries. This paper describes how three recent surveys performed in California have been used to provide an overall picture of long distance travel within the state. The three surveys are the 2011 Harris On-Line Panel Long Distance survey performed for the California High Speed Rail Authority (CAHSRA) and the 2012-2013 California Statewide Household Travel Survey Daily Diary and Long Distance Travel Recall Surveys performed for the California Department of Transportation (Caltrans).