Crime Perceptions, Urban Transport Choices and Support for Climate Change Initiatives

Last registered on June 24, 2024


Trial Information

General Information

Crime Perceptions, Urban Transport Choices and Support for Climate Change Initiatives
Initial registration date
June 03, 2024

Initial registration date is when the trial was registered.

It corresponds to when the registration was submitted to the Registry to be reviewed for publication.

First published
June 24, 2024, 11:53 AM EDT

First published corresponds to when the trial was first made public on the Registry after being reviewed.



Primary Investigator

University of Southern California

Other Primary Investigator(s)

PI Affiliation
University of Southern California
PI Affiliation

Additional Trial Information

Start date
End date
Secondary IDs
Prior work
This trial does not extend or rely on any prior RCTs.
This study aims to find causal evidence on the relationship between safety in the public transport and commuters' transport mode choice. This study has three main research questions to be answered. First, we want to get an estimate of what is the willingness to pay for safety in the public transport. Second, for a given trip, up to what extent would people substitute their choice of transport mode from private taxis (say, Uber or Lyft) to bus if safety in the latter increases. Finally, we want to understand whether higher insecurity in the public transport system crowds out support for other policies (in particular, environmental policies). We study this through a non-incetivized lab experiment carried on in eight Latin American countries. The study is divided in three different experiments, where participants are randomized in different groups where each group is presented with a different set of information. While in the first two experiments participants are asked to choose between different transport modes, in the last one we ask the participants to allocate a budget between four policies as if they were policymakers. We hope that the results of this study would contribute to understand whether increasing the safety in the public transport system plays a role in tackling climate change by substituting from private to public transport modes.
External Link(s)

Registration Citation

De Martini, Santiago, Juan Gonzalez and Santiago Perez-Vincent. 2024. "Crime Perceptions, Urban Transport Choices and Support for Climate Change Initiatives." AEA RCT Registry. June 24.
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Experimental Details


Intervention Start Date
Intervention End Date

Primary Outcomes

Primary Outcomes (end points)
First, willingness to pay to use a bus in a given trip under different safety levels. Probability of choosing a bus over a private taxi for different bus safety levels. How the allocation of a budget changes when participants are exposed to different newspaper articles that suggest that the public transport system is safe, not safe or a newspaper article that says nothing about safety. Finally, we are interested in capturing the order in which participants click the 'tags' of different attributes of transport modes (mousetracking). Participants are asked to click on different boxes that have a tag that correspond to the topic of the information hidden in each one of them to see such information.
Primary Outcomes (explanation)
We follow the Gabor-Granger method to construct willingness to pay measures.

Secondary Outcomes

Secondary Outcomes (end points)
Secondary Outcomes (explanation)

Experimental Design

Experimental Design
The experiment is divided into three sub-experiments which we denote as parts 1-3. Morover, agents answer questions about other control variables (such as demographics).

In part 1, subjects will have to choose between two types of buses (Bus A and Bus B) to do a given trip. The information of each bus is presented in two columns, but each piece of information is hidden behind a box that has the title of the information contained in each of them. To see the information behind each box, the participants have to click in the corresponding box. There are boxes (pieces of information) about 4 attributes: estimated trip duration (in minutes), estimated emissions (in g of CO2), safety (in number of crimes in the bus) and price (in local currency). Regarding the safety information of Bus B, subjects will be randomized into different levels (+30%, +10%, -10%, -30% in the number of crimes committed on public transportation with respect to the average crime level in buses in their city), and the crime level of Bus A will always be equal to 'same number of crime of buses as the average in your city'. For groups +10% and +30% the price presented of Bus B will be 50% lower than the one of Bus A, and for groups -10% and -30% the price is 50% higher. We proced through the Gabor-Granger method to capture the indifference price between each transport mode.

In part 2, will face a choice between two options: an Uber ride at its usual local price, and an equivalent bus ride at its usual local price; we will present the same attributes as in part 1 The attributes will be presented in two columns, all at once (no need to click on boxes in this part). Moreover, subjects will be randomized between the same levels of bus safety as in part one: +30%, +10%, -10%, -30%. Then, participants will choose whether they would use the private or public transportation option. Following the Gabor-Granger method again, participants who choose public (private) transport will then face the same choice but with public transportation price X% higher (cheaper).

In part 3, we will randomly allocate the participants in one of three groups: two treatments and one control. In one of the treatments, we will present a newspaper article that suggests that the public transport in their city is safe and in the other treatment an article that suggests that it is not safe (and we present a 'neutral' or 'placebo' article the control group). Then, we will tell the participants to think that they are the policymakers of their city and that they have a budget of 120 thousand dollars to allocate between four policies: environmental, efficiency, price and safety. The agents then give their allocation choice and we are interested in studying whether being exposed to different newspaper articles (that aims to vary the safety perception in the public transport system of their city) changes the allocation of the budget.
Experimental Design Details
Randomization Method
Randomization done in office by a computer
Randomization Unit
Was the treatment clustered?

Experiment Characteristics

Sample size: planned number of clusters
Sample size: planned number of observations
Sample size (or number of clusters) by treatment arms
Evenly distributed. For the first two experiments there are 4 arms, so we expect to have approximately 1350 individuals in each one of them. In the last experiment, there are 3 arms, so we expect to have approximately 1800 participants in each arm.
Minimum detectable effect size for main outcomes (accounting for sample design and clustering)

Institutional Review Boards (IRBs)

IRB Name
IRB Approval Date
IRB Approval Number


Post Trial Information

Study Withdrawal

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Is the intervention completed?
Data Collection Complete
Data Publication

Data Publication

Is public data available?

Program Files

Program Files
Reports, Papers & Other Materials

Relevant Paper(s)

Reports & Other Materials