AEA RCT Registry

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The impact of fare-free public transport on travel behavior

Last registered on December 24, 2018

View Trial History

Pre-Trial

Trial Information

General Information

Title

The impact of fare-free public transport on travel behavior

RCT ID

AEARCTR-0003542

Initial registration date

December 21, 2018

Last updated

December 24, 2018 4:33 AM EST

Location(s)

Country

Chile

Region

Primary Investigator

Name

Hugo Silva

Affiliation

Contact Primary Investigator

Other Primary Investigator(s)

PI Name

Owen Bull

PI Affiliation

PI Name

Juan Muñoz

PI Affiliation

Additional Trial Information

Status

Completed

Start date

2016-10-03

End date

2018-08-31

Keywords

Environment & Energy, Other

Additional Keywords

Transport

JEL code(s)

R48; H23; R41

Secondary IDs

Abstract

We investigate the impact of fare-free public transport on travel behavior. We randomly assigned a public transportation pass to individuals working in Santiago (Chile) that allowed them unlimited travel without paying and evaluated its effects over two weeks. The results show that access to fare-free public transport increased the total number of trips, regardless of the mode, by 11%. Interestingly, this trip generation effect is mostly driven by an increase in the number of trips made by modes other than public transport. The average treatment effect public transport trips is positive yet not significant. Therefore we find evidence of a trip generation effect, that there is no transport-mode substitution and, as a consequence, no evidence that fare-free public transport reduces negative externalities from car travel.

External Link(s)

Registration Citation

Citation

Bull, Owen, Juan Muñoz and Hugo Silva. 2018. "The impact of fare-free public transport on travel behavior." AEA RCT Registry. December 24. https://doi.org/10.1257/rct.3542-1.0.

Former Citation

Bull, Owen et al. 2018. "The impact of fare-free public transport on travel behavior." AEA RCT Registry. December 24. http://www.socialscienceregistry.org/trials/3542/history/39547.

Sponsors & Partners

Experimental Details

Interventions

Intervention(s)

Intervention Start Date

2016-10-24

Intervention End Date

2017-04-13

Primary Outcomes

Primary Outcomes (end points)

Total trips; trips made by public transport; trips made by modes other than public transport.

Primary Outcomes (explanation)

Number of trips taken in a two-week period

Secondary Outcomes

Secondary Outcomes (end points)

Secondary Outcomes (explanation)

Experimental Design

The focus of our study was the Santiago labor force, which was selected as our group of interest for many reasons. First, commuting trips are a large share of the trips in Santiago. Commuting represents 74% of the morning peak trips, and 42% of the commuting trips are made by public transport. Commuting trips are also important within the public transport system, as they represent 44% of the total number of trips made by public transport in Santiago in a workday.

The evaluation was done in 13 firms in two periods. The first period began in October 2016 with three employers and the second period started in March 2017 with the remaining ten firms. People within each firm applied for participation in the experiment by filling a survey about their basic information and socioeconomic characteristics. Selection of people for participation in the trial was aimed at individuals whose working schedules displayed enough regularity, such as working every week, to ensure some degree of comparability between the work weeks covered by the study period. We excluded individuals who already enjoyed government-financed fare discounts. Participants were requested to record every trip they took in a trip diary, documenting the trip purpose, start time (departure from place of activity), end time (arrival at destination), the location of destination (the district in Santiago) and mode of transport.

The randomization was carried out at the individual level in each of the 13 firms after the first week of recording trips. Participants assigned to the treatment group were given a public transport card that allowed them to travel on the entire public transport system (including buses and metro) for two weeks without paying. Participants in the control group were given a lump-sum transfer at the end of the experiment of US $22.5. Stratified randomization was performed within each firm, when the sample size was big enough to allow for it, according to the participants' intensity of public transport use (measured on their Santiago fare card data for the 90 days immediately previous to the study period).

Experimental Design Details

Randomization Method

Randomization done in an office by a computer

Randomization Unit

Randomization at the individual level

Was the treatment clustered?

Experiment Characteristics

Sample size: planned number of clusters

13 firms

Sample size: planned number of observations

200 individuals

Sample size (or number of clusters) by treatment arms

101 individuals as control and 106 individuals treated with a two-week public transport pass

Minimum detectable effect size for main outcomes (accounting for sample design and clustering)

Outcome: total trips made by public transport. MDE=1,329701715, SD=2,986540139; 80% power. Outcome: total trips. MDE=1,451911425, SD=3,261025912; 80% power. Outcome: total trips in modes other than public transport. MDE=1,582815793, SD=3,555040084; 80% power.

Supporting Documents and Materials

IRB

INSTITUTIONAL REVIEW BOARDS (IRBs)

IRB Name

IRB Approval Date

IRB Approval Number

Analysis Plan