Zusha! A randomized behavior change road safety intervention
Last registered on November 13, 2014


Trial Information
General Information
Zusha! A randomized behavior change road safety intervention
Initial registration date
November 13, 2014
Last updated
November 13, 2014 5:06 PM EST
Primary Investigator
Georgetown University
Other Primary Investigator(s)
PI Affiliation
Georgetown University
Additional Trial Information
Start date
End date
Secondary IDs
Road accidents kill 1.3 million people each year, most in the developing world. We test the efficacy of evocative messages, delivered on stickers placed inside Kenyan matatus, or minibuses, in reducing road accidents. We randomize the intervention – which nudges passengers to complain to their drivers directly – across 12,000 vehicles. We use insurance claims data and vehicle speeds to assess the impact of the interventions. We also evaluate a complementary radio campaign aired during randomly selected weeks over a 5 month period.
External Link(s)
Registration Citation
Habyarimana, James and William Jack. 2014. "Zusha! A randomized behavior change road safety intervention." AEA RCT Registry. November 13. https://doi.org/10.1257/rct.554-1.0.
Former Citation
Habyarimana, James, William Jack and William Jack. 2014. "Zusha! A randomized behavior change road safety intervention." AEA RCT Registry. November 13. http://www.socialscienceregistry.org/trials/554/history/3081.
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Experimental Details
Our intervention is aimed at promoting agency among matatu (minibus) passengers, empowering them to challenge the driver to slow down and drive less recklessly if they felt their safety was compromised. To this end, we post stickers with evocative messages inside the vehicles, exhorting the passengers to act, with phrases like “Don’t let a reckless driver get away with murder,” and others. We test the efficacy of different kinds of messages, including the role of images in general in eliciting a response, and the relative merits of using fear versus reason to motivate behavior change. We also assess the impact of messages promoting collective action compared with those aimed simply at alleviating individual-level constraints.
Intervention Start Date
Intervention End Date
Primary Outcomes
Primary Outcomes (end points)
Outcomes are insurance claims and speeds recorded by GPS on study vehicles.
Primary Outcomes (explanation)
Secondary Outcomes
Secondary Outcomes (end points)
Secondary Outcomes (explanation)
Experimental Design
Experimental Design
We randomly assign vehicles across 8 treatment groups, one placebo, and a control. Assignment and distribution of stickers occurs at the point of sale of insurance coverage.
Experimental Design Details
Randomization Method
Randomization conducted via computer generation of a random number at the point of recruitment.
Randomization Unit
Randomized at the individual level to 14-seater minibuses.
Was the treatment clustered?
Experiment Characteristics
Sample size: planned number of clusters
12,000 vehicles
Sample size: planned number of observations
12,000 vehicles
Sample size (or number of clusters) by treatment arms
1,000 vehicles in each treatment arm, 2,000 in the placebo arm, 2,000 in the control.
Minimum detectable effect size for main outcomes (accounting for sample design and clustering)
There is no clustering in the assignment of treatment. We have 80% power to detect a 50% reduction in annual accident rates (based on 2009/10 insurance claims data) between the main message groups and the control group.
IRB Name
Georgetown IRB
IRB Approval Date
IRB Approval Number
Post Trial Information
Study Withdrawal
Is the intervention completed?
Is data collection complete?
Data Publication
Data Publication
Is public data available?
Program Files
Program Files
Reports and Papers
Preliminary Reports
Relevant Papers