General Information
Project description
Using sustainable transportation alternatives can often be hindered by car dependence (Haustein, 2021). Within the context of Santa Monica, for example, approximately 75% of Santa Monica residents choose single occupancy vehicle (SOV) commutes to work, and over 50% of households own more than one vehicle (Data USA, n.d.). More generally, vehicle transportation accounts for 62% of greenhouse gas emissions in the city, making it the largest emissions contributor (Johnstone, 2021).
However, notably behavioural science and general research provide a large body of evidence that people respond to incentives (Gneezy et al., 2020) and that sustainability-linked behaviours can be encouraged through nudging and salient incentives (Schwartz et al. 2019). In one conducted in Seattle in 2000, for example, 86 households were challenged to not use their additional car over 6-9 weeks to earn $80 weekly. Researchers found a 27% decrease in drive-alone miles, an increase in sustainable travel miles, and that 26% of households sold their extra car (Bauer et al., 2018).
However, research gaps primarily lie in understanding the effectiveness of cash incentives on travel behaviour through randomised controlled trials and more robust measurement. Based on this and using insights from Seattle’s program, we designed a field study to explore reducing vehicle miles travelled (VMT) in Santa Monica.
References:
Data USA. (n.d.). Santa Monica, CA. Retrieved February 14, 2024, from datausa.io/profile/geo/santa-monica-ca/
Bauer, J., Bedsole, L., Snyder, K., Neuner, M., & Smith, M. C. (2018). Expanding traveler choices through the use of incentives: A compendium of examples (No. FHWA-HOP-18-071). United States. Federal Highway Administration.
Gneezy, U., Kajackaite, A., & Meier, S. (2020). Incentive-based interventions. In The Handbook of Behavior Change (pp. 523-536). Cambridge University Press.
Haustein, S. (2021). The hidden value of car ownership. Nature Sustainability, 4(9), 752-753.
Johnstone, D. L. (2021). U.N. Releases New Report & Santa Monica’s 2019-2020 GHG Emissions Are Calculated. City of Santa Monica. Retrieved February 14, 2024, from www.santamonica.gov/blog/u-n-releases-new-report-santa-monica-s-2019-2020-ghg-emissions-are-calculated
Schwartz, D., Milfont, T. L., & Hilton, D. (2019). The interplay between intrinsic motivation, financial incentives and nudges in sustainable consumption. In A research agenda for economic psychology (pp. 87-103).
Detailed information
Final report: Is there a final report presenting the results and conclusions of this project?
Data Exclusion
To qualify for participation in the "One Car Challenge", each participant must meet the following inclusion criteria:
• Participant owns or has access to at least 2 vehicles within their primary household
• Participant is at least 21 years old
• Participant currently lives in Santa Monica and is not planning to move out of Santa Monica within the next 3 months
Ideally, participants will live in 2-vehicle households and will not have any extended trips planned within 3 months. Addresses, names, and contact information will be checked for duplicates to ensure that there is only 1 participant in each household. If there are duplicates, only the first applicant will be eligible for participation (unless one applicant completed more of the required information for participation). Household duplicates were removed from the final dataset.
The following exclusion criteria was used for participant’s weekly odometer readings:
• Self-reported cheating for 5-week testing periods
• Odometer reading discrepancies (odometer reading declined or was >2 SDs of average mileage changes)
Treatment of Missing Data
Missing data will be handled by the default approaches of the R packages used in analysis, which involved listwise deletion.
Additional information
United States
Santa Monica, California
Who is behind the project?
Project status:
Completed
Methods
What is the project about?
Date published:
27 September 2024