Increasing policy acceptance of road pricing policy

Last registered on May 17, 2023


Trial Information

General Information

Increasing policy acceptance of road pricing policy
Initial registration date
May 12, 2023

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
May 17, 2023, 2:41 PM EDT

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


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Primary Investigator

Institute of Transport Economics

Other Primary Investigator(s)

PI Affiliation
University Carlos III

Additional Trial Information

On going
Start date
End date
Secondary IDs
Prior work
This trial is based on or builds upon one or more prior RCTs.
This is an interdisciplinary project that will create new knowledge and sound empirical evidence acquired by experimentation that will fill important knowledge gaps within transport, behavioral, environmental and political economics. By using a mix of methods from economics, psychology, political and data science, and gathering a rich set of different data, the project aims to answer a set of bold research questions that will contribute to the shift to a sustainable transport system. The overarching focus is to address the tradeoff between policy effectiveness and acceptability in the transport sector, in search for the optimal balance. We develop ad-hoc choice experiments to understand how to facilitate policy acceptability, specifically applied to the transport sector.
External Link(s)

Registration Citation

Ciccone, Alice and Francesca Lipari. 2023. "Increasing policy acceptance of road pricing policy." AEA RCT Registry. May 17.
Sponsors & Partners

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Experimental Details


We develop an ad-hoc choice experiment to understand what factors are most important for individual acceptance of an innovative transport policy: road pricing. In the choice experiment people are asked to choose between two slightly different road pricing policies and the status quo (no road pricing). We implement the experiments in two cities, Madrid and Oslo.

Intervention Start Date
Intervention End Date

Primary Outcomes

Primary Outcomes (end points)
Choice of policy vs status quo
Primary Outcomes (explanation)

Secondary Outcomes

Secondary Outcomes (end points)
effect of prices and EV discount
Effect of the use of revenues
Secondary Outcomes (explanation)

Experimental Design

Experimental Design
To understand how to facilitate the acceptability of a policy change, we randomly divide responders into three/four treatment groups and a control group. Respondents in each treatment group face a different information, while the control group does not receive any information. Then we implement the same choice experiment for everyone.
Experimental Design Details
Not available
Randomization Method
Subjects are randomly assigned to one of the four treatments, i.e. Control, Treatment 1, Treatment 2 and Treatment 3. We will check whether the randomization assumption is true by comparing the average and distributions of the socio-economic variables.
Randomization Unit
Was the treatment clustered?

Experiment Characteristics

Sample size: planned number of clusters
5 arms (1 control and 4 treatments)
Sample size: planned number of observations
We will recruit and start the experiment with 500-1000 subjects.100-200 in each treatment. This number is based on a power analysis calibrated on a pilot analysis run in Madrid in July 2022. The final number of subjects will be influenced by the drop-out rate, which is out of our control and by the recruitment in each country. If needed additional recruitment will be carried out over time.
Sample size (or number of clusters) by treatment arms
100-200 individual per 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
Analysis Plan

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