Does a Grande Latte Really Stir Up Gridlock? Stops in Commute Journeys and Incremental Travel

Does a stop a commuter makes on the way to or from work adversely affect peak-period traffic? This question is addressed by examining the effects of stops made as part of commute journeys upon daily, as well as peak-period, travel time and distance, using a six-week travel diary data set from Germany. Increments in travel time and distance due to stops made in commute journeys are evaluated and used in the study, and a panel regression analysis is performed to determine contributions of stops of different types to travel time and distance. Findings include: public transit commuters on average make more stops as part of their commute journeys than do auto or non-motorized commuters; the travel time and distance of a commute journey increase with the number of stops it contains; and incorporating stops as part of commute journeys tends to make daily travel more efficient with more distances traversed with relatively less time, compared with the case where the same number of stops are all made outside commute journeys. Nonetheless, stops in commute journeys do add to peak-period travel time and distance. Stops made before work do not produce very much incremental travel in the morning peak period. Stops made after work, on the other hand, substantially add to peak-period travel time and distance as well as daily travel time and distance. In particular, a home-based journey made after returning home contributes to afternoon peak traffic more than does a stop in a work-to-home commute journey. TRB 2006 Annual Meeting CD-ROM Paper revised from original submittal. Ryuichi Kitamura and Yusak O. Susilo 1