No Time Like the Present: The Effects of On-Demand Trips for Paratransit Customers on Rider Mobility, Wellbeing, and Health

Last registered on January 05, 2026

Pre-Trial

Trial Information

General Information

Title
No Time Like the Present: The Effects of On-Demand Trips for Paratransit Customers on Rider Mobility, Wellbeing, and Health
RCT ID
AEARCTR-0017496
Initial registration date
December 22, 2025

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 05, 2026, 7:16 AM EST

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

Locations

There is information in this trial unavailable to the public. Use the button below to request access.

Request Information

Primary Investigator

Affiliation
University of Warwick

Other Primary Investigator(s)

PI Affiliation
Icahn School of Medicine at Mount Sinai
PI Affiliation
Texas A&M University

Additional Trial Information

Status
In development
Start date
2026-05-01
End date
2030-05-01
Secondary IDs
Prior work
This trial does not extend or rely on any prior RCTs.
Abstract
About a quarter of Americans with disabilities are living in poverty. One contributing factor is a lack of physical mobility, which may limit access to health care, social relationships, and economic participation. Although the Americans with Disabilities Act requires public transit agencies to provide riders unable to use fixed-route transit with paratransit alternatives, paratransit users are generally required to book trips a day in advance, constraining flexibility. In this study, we will conduct a randomized controlled trial of King County Metro’s new Access On-Demand program, which allows paratransit users to book same-day trips. This is the first study to evaluate the effects of an on-demand transportation option on paratransit customers’ mobility, transportation security, health, and wellbeing. The research design, which will leverage administrative data complemented by surveys, is the product of a long collaboration between the research team and King County Metro and is informed by an nonexperimental pilot.
External Link(s)

Registration Citation

Citation
Cassidy, Michael, Ludovica Gazze and Melissa Gentry. 2026. "No Time Like the Present: The Effects of On-Demand Trips for Paratransit Customers on Rider Mobility, Wellbeing, and Health." AEA RCT Registry. January 05. https://doi.org/10.1257/rct.17496-1.0
Sponsors & Partners

There is information in this trial unavailable to the public. Use the button below to request access.

Request Information
Experimental Details

Interventions

Intervention(s)
The Americans with Disabilities Act (ADA) requires public transit agencies to provide paratransit services for individuals whose disabilities preclude them from using fixed-route transit, such as buses or subways. This service is meant to be comparable in terms of service area and availability. Nevertheless, federal regulations allow paratransit to remain incongruous in one important respect: most services require riders to schedule trips a day in advance, limiting flexibility and spontaneity in ways that may be detrimental to rider mobility and wellbeing. To fill this gap, King County Metro (KCM), a public transportation agency serving the Seattle, Washington, area, has introduced an “Access On-Demand” (AOD) program, which allows paratransit users to take subsidized trips through a third-party platform without advanced reservations. The cost to riders is that of a bus ticket, $2.75, for trips that would cost $15-$50 through rideshare apps (although these are not generally available to wheelchair users).

This study will evaluate the impacts of KCM's on-demand program on paratransit customers’ mobility, transportation security, health, and wellbeing. We will use rich administrative and survey data to answer two primary research questions: (1) How does an accessible on-demand transportation option affect rider mobility, transportation security, and satisfaction? (2) How does an accessible on-demand transportation option affect riders’ physical and mental health, wellbeing, and access to health care? We hypothesize that the flexibility offered by AOD will benefit riders in each of these domains.
Intervention Start Date
2026-07-01
Intervention End Date
2028-05-01

Primary Outcomes

Primary Outcomes (end points)
mobility - measured as trips taken and distance traveled using King County Metro admin data
transportation security - measured using survey data one year after enrollment into the intervention
healthcare utilization - measured using Washington State All Payer Claims Data (APCD)
Primary Outcomes (explanation)

Secondary Outcomes

Secondary Outcomes (end points)
General wellbeing - measured using survey data one year after enrollment into the intervention
Secondary Outcomes (explanation)

Experimental Design

Experimental Design
Eligible paratransit customers will be randomized to a treatment group that is offered enrollment in the Access On-Demand program and a control group that is not offered enrollment. Both groups will sustain access to traditional paratransit services.
Experimental Design Details
Not available
Randomization Method
Randomization done in office by computer
Randomization Unit
Individual
Was the treatment clustered?
No

Experiment Characteristics

Sample size: planned number of clusters
N/A
Sample size: planned number of observations
1000-1500 residents of King County, WA, who are paratransit customers
Sample size (or number of clusters) by treatment arms
1000-1500 total participants with half assigned to the treatment group and half to the control group
Minimum detectable effect size for main outcomes (accounting for sample design and clustering)
Assuming 80 percent power, a significance level of 0.05, a sample size of 1,000, and 40 percent take-up, we should be able to detect individual-level effects of 0.2 standard deviations.
IRB

Institutional Review Boards (IRBs)

IRB Name
Icahn School of Medicine at Mount Sinai
IRB Approval Date
0012-04-25
IRB Approval Number
STUDY 25-01124