Text-Message Intervention to Reduce Handheld Phone Use Among Drivers

Last registered on January 31, 2024

View Trial History

Pre-Trial

Trial Information

General Information

Title

Text-Message Intervention to Reduce Handheld Phone Use Among Drivers

RCT ID

AEARCTR-0012887

Initial registration date

January 25, 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

January 31, 2024, 11:44 AM EST

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

Locations

Country

United States of America

Region

Primary Investigator

Name

Yizhou Jin

Affiliation

University of Toronto

Contact Primary Investigator

Other Primary Investigator(s)

Additional Trial Information

Status

Completed

Start date

2020-01-01

End date

2020-03-10

Keywords

Behavior

Additional Keywords

moral hazard, inattention, risky driving, handheld phone use, text and drive

JEL code(s)

Secondary IDs

Prior work

This trial does not extend or rely on any prior RCTs.

Abstract

we collaborate with a transportation company that provides on-demand car rides and self-insures against traffic accidents its drivers incur. Using drivers’ smartphone sensor data, we can accurately identify handheld phone use (“HPU”) behavior. We sent a simple text message to a random subset of drivers with high HPU. The message called attention to their HPU behavior and reminded them that repeated passenger complaints of unsafe driving could lead to suspension.

External Link(s)

Registration Citation

Citation

Jin, Yizhou. 2024. "Text-Message Intervention to Reduce Handheld Phone Use Among Drivers." AEA RCT Registry. January 31. https://doi.org/10.1257/rct.12887-1.0

Sponsors & Partners

Experimental Details

Interventions

Intervention(s)

We sent a one-time text message to treated drivers with records of frequent handheld-phone-use: ”Our app shows you may be holding your phone while driving. Passenger reports of unsafe driving, like handheld phone use, can lead to suspension.”

Intervention Start Date

2020-01-21

Intervention End Date

2020-01-22

Primary Outcomes

Primary Outcomes (end points)

Frequency of handheld phone use

Primary Outcomes (explanation)

We hypothesize that the text-message would trigger a reduction in the frequency of handheld phone use.

Secondary Outcomes

Secondary Outcomes (end points)

Driving hours, other risky behaviors such as harsh acceleration.

Secondary Outcomes (explanation)

Experimental Design

On the intervention day, we pre-selected a 30-minute window (3-3:30 pm EST). All eligible drivers starting a shift during this period are randomized into the treatment group with 50% probability.

Experimental Design Details

Randomization Method

Randomization is done via the company's internal communications systems.

Randomization Unit

Driver

Was the treatment clustered?

Yes

Experiment Characteristics

Sample size: planned number of clusters

Completed: 467 treated drivers; 508 control-group drivers (including 21 drivers randomized into treatment but unreachable by text message due to connectivity or device issues).

Sample size: planned number of observations

277,649 trips

Sample size (or number of clusters) by treatment arms

Among treated drivers, 81,655 trips were observed after the intervention and 45,362 before. 150,632 trips are observed for control-group drivers.

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

The probability of rejecting the null hypothesis (if the null is false) exceeds 95% as long as the treatment generates an increase or decrease in HPU frequency of 5.92% (on that day). Pooling across all days, the minimum detectable effect size is 0.85%.

Supporting Documents and Materials

IRB