This research was funded by the National Institute for Transportation and Communities, or NITC, a program of TREC at Portland State University. Funding was also provided by Oregon Department of Transportation (ODOT), the City of Hillsboro, and Washington County.
Oregon. Department of Transportation, Transportation -- Planning -- Oregon
Eco-driving consists of using energy-efficient approaches to driving aimed at reducing fuel consumption and, ultimately, CO2 emissions. A previous study found that an EcoDrive informational campaign was effective at increasing the use of eco-driving behaviors, but only when employees perceived that their supervisor supported the program and when they were personally motivated to perform the eco-driving behaviors. In order to build upon the findings of our previous study, the present study focused on increasing the use of eco-driving behaviors through an informational eco-driving campaign combined with supervisor training to support the use of eco-driving practices.
In this study we collected baseline measures of driving knowledge, attitudes, and behaviors from employees at three organizations, as well as follow-up data collected at two months (Time 2) and six months post-intervention (Time 3). Implementing a quasi-experimental design with a control group (informational campaign only) and an experimental group (informational campaign combined with supervisor training), we tested the incremental effectiveness of supervisor training compared to the effect of an informational campaign alone.
In total, 19 supervisors received supervisor training (supervisor training group) and 10 supervisors were provided with the informational campaign materials only (control group). We collected data from 144 unique participants across the three time points, and of these responses we were able to match responses for 50 participants from Time 1 to Time 2 and 48 from Time 1 to Time 3. We were also able to match responses from 38 participants across all three time points; however, because our interest was in change from baseline, and in order to increase our statistical power, analyses were conducted comparing Time 1 to Time 2 and Time 1 to Time 3 data. We assessed changes in self-reported knowledge, attitudes, and behaviors using mixed method ANOVAs to assess the within-person change across time points and compare the effectiveness of the intervention between the control and supervisor training groups.
We found that, in general, participants reported using eco-driving behaviors more often in the follow-up surveys compared to baseline measures. However, we did not find direct support for the supervisor training intervention providing an incremental increase in eco-driving behaviors and attitudes compared to the informational campaign alone. On the other hand, we did find that supervisor support, frequency of communication about eco-driving, and the percentage of employees who viewed the EcoDrive materials were greater in the supervisor training group compared to the control group. Additionally, employees in the supervisor training group rated the EcoDrive materials as more useful compared to the control group.
Based on these findings, the supervisor training seemed to be effective in improving indicators of supervisor support; however, it may be that our limited sample size did not allow us to find statistically significant differences between the two groups in eco-driving behaviors. In this report we discuss in more detail the basis for this study, the implementation of the intervention, the results, and potential explanations for our findings in order to inform future studies. We also provide a detailed account of the methodology used in this study.
Truxillo, D.M., MacArthur, J., Brady, G., Hammer, L., & Bauer, T. (2016). Evaluation of a Supervisor Training Program for ODOT’s EcoDrive Program. NITC-RR-781 Portland, OR: Transportation Research and Education Center (TREC). https://doi.org/10.15760/trec.155