Exploring the Longest Trip: A New Look on the Impact of Long Road Trips on VMT
Available online at: TRB
Tal, Gil and Michael A. Nicholas (2016) Exploring the Longest Trip: A New Look on the Impact of Long Road Trips on VMT. Transportation Research Board
Long-distance road trips that may accumulate to a significant portion of the total household Vehicle Miles Traveled (VMT), are difficult to survey and therefore are under-reported and underestimated in travel behavior studies that focus on VMT forecasting and modeling. Understanding long trips is a critical part in understanding the impact of policies aimed to reduce VMT. Similarly long trips are critical in understanding the potential of battery electric vehicles which, in most cases, cannot travel long trips without long charging stops. This study explores new methods to survey long-distance road trips using a new web map survey method. We study one trip, the longest vehicle trip in the last 12 month. For 40% of the households in our study one long trip accounts for more than 5% of the annual gas used. For 20%, one long trip accounts for more than 5% of yearly miles. We show that long-distance road trips constitute a significant share of some household’s VMT, and this share is correlated with socio-demographic, location, travel behavior, and vehicle ownership characteristics. The main barriers to studying long-distance road trips are the rarity and complexity of these trips. The Web-map tool addresses 15 limitations of conventional methods that focuses on long-distance trips.