Expanding Traveler Choices through the Use of Incentives: A Compendium of Examples

5. Applying Incentives to Eliminate Trips

Florida Idriveless Research Program

After looking into different financial incentives offered for transportation demand management and how to improve upon these offers, the Florida DOT (FDOT) and the Center for Urban Transportation Research (CUTR) at the University of South Florida developed a controlled, quasi-experimental initiative called "Idriveless." The program was designed to provide financial rewards to people who reduced their vehicle miles traveled (VMT). FDOT measured VMT every 2 weeks throughout the study period, and participants were compensated based on the number of miles they reduced.

Incentives were structured based on how many VMT participants were able to cut from their baseline trips. Once participants were able to reduce 20 VMT, they received a $5 payment. The incentive structure was increased by $5 for every additional 20 miles reduced, with a maximum payout of $40 at 160 VMT or more reduced. An additional $20 was added to the 10th week of the study to retain participants in the study and complete the exit interview in a timely manner. The maximum payout for those who eliminated 160 or more VMT and completed the survey was $200. Participants were recruited initially based on positive responses to an interest survey. Additional recruitment was performed through a database of registered vehicle owners in Florida – nearly 50,000 registered vehicle owners in Miami-Dade, Broward, Hillsborough, and Duval counties were contacted by email. Seventy-eight participants were enrolled in the study, with a minimum of 20 participants in each study group, including the control group. By the end of the 10th week, the end of the study, 61 participants were still participating in the study. (Lee et al., 2013)

To evaluate the incentive structures in this study, different schemes were adopted, and participants were randomly assigned to each scheme. Group A was a traditional incentive scheme, providing cash rewards after participants completed and reported their saved VMT. Group B was assigned a new incentive scheme, which was designed to provide the incentive in advance of VMT savings based on a pre-committed VMT reduction. If a participant in Group B was unable to meet the pre-committed VMT reduction, they were required to return the incentive. This scheme was designed based on the "prospect theory" and the "loss aversion effect," where people have a tendency to prefer avoiding losses than to acquiring gains. Group C was the control group.

Throughout the study, participants in Group A, those with a reactionary incentive payout, maintained nearly 10 percent or higher VMT reduction each week. Group B, with the pre- incentive payout, achieved significant VMT savings in the first 6 weeks of the program, but reduced VMT reduction during the rest of the study period. Approximately 50 percent of both Groups A and B participants were able to save VMT during the study—so much so that a significant amount of VMT was saved in both groups beyond that for which the participants were compensated. The control group, Group C, showed an average of zero percent change in VMT from the baseline. With such a small sample size, the researchers did not reach firm conclusions on whether up-front or reactionary payments would produce more behavior change. (Lee et al., 2013)

During the exit interviews, participants were asked to identify their primary strategies for saving VMT during the time period. A majority of respondents claimed to have a strategy, and the most common responses included reducing number of trips or trip chaining, carpooling, taking public transportation, biking or walking to work, and telecommuting. (Lee et al., 2013)

For more information, see: http://www.fdot.gov/research/completed_proj/summary_pto/fdot-bdk85-977-41-sum.pdf.

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