This clinical trial will look at whether young adults with intellectual and developmental disabilities (YA-IDD) have better outcomes when a travel training intervention called Ready to Ride (R2R) is taught by a specially trained Peer Supporter (PS) who shares the lived experience of having an IDD than YA-IDD who are taught Ready to Ride by staff at their community services organization. The aspects of life being looked at are loneliness, satisfaction with social activities, travel skills, service use and access, employment, and health related quality of life.

The researchers think the following things will happen.

1. YA-IDD who learn from a Peer Supporter will report significantly higher satisfaction with social activities, increased social connectedness and significantly less loneliness compared to YA who are taught organization staff.
2. Both groups will learn the same amount of travel skills.
3. YA-IDD who learn from a Peer Supporter will show larger increases in access to community-based services, transportation use, employment and health related services after 4 months than the YA taught by organizational staff.

This clinical trial has 2 aims.

Aim 1. Compare the effectiveness of peer support (R2R-PS) or staff delivered (R2R-S) Ready to Ride (R2R) travel intervention on loneliness, satisfaction with social activities, and travel skills (primary outcomes), and service use/access, transportation use, employment, social connectedness, and health related quality of life (secondary outcomes) for YA with IDD.

Hypothesis 1.1: YA receiving R2R-PS will report significantly higher satisfaction with social activities, increased social connectedness, and significantly less loneliness compared to YA receiving R2R-S.

Hypothesis 1.2: The travel skills demonstrated by YA receiving R2R-PS will be no worse than travel skills demonstrated by YA receiving R2R-S. We use a non-inferiority approach in response to community service organizations' request for evidence that peer support delivery does not lead to poor outcomes.

Hypothesis 1.3: YA receiving R2R-PS will demonstrate significantly greater improvements in service use/access, transportation use, employment, and health related quality of life 4 months post intervention compared to YA receiving R2R-S.

Aim 2: Evaluate heterogeneity of treatment response by assessing differences in R2R outcomes across characteristics of groups (race and ethnicity, anxiety, adaptive behavior) and context (transportation availability).

Hypothesis 2.1. There will be no difference in treatment effect for YA who identify as white, non-Hispanic and those identifying as Black, Hispanic, Asian, or other race/ethnicity.

Hypothesis 2.2. There will be greater gains for YA with lower levels of adaptive behavior completing R2R, based on past research that identified that participants with intellectual disabilities (ID) with lower levels of adaptive behaviors demonstrated greater improvements in transportation skills than those with a developmental disability but without an ID after receiving the R2R intervention.37 Hypothesis 2.3. There will be no difference in primary outcomes for YA living in areas with less transportation availability, given R2R's individualized travel training approach.

Hypothesis 2.4. There will be greater gains for YA in transportation outcomes who report lower levels of anxiety, given that anxiety in linked with reduced transportation use.

Inclusion Criteria:

• Between the ages of 18 to 27 years old during the start of the study
• Receives services at one of the eight community service organizations participating in the study.
• Meets the federal diagnosis of a developmental disability (DD)
• Qualifies for services related to their DD.
• Scores >28 on the Transportation Prescreening Assessment (indicating readiness for travel).

Exclusion Criteria:

• Independently uses public transportation >4 times/month.
• Is not able to independently mobilize through walking or use of a mobility device.
• Has significant non-corrected visual impairments.

We will submit de-identified IPD data and associated documentation to the Interuniversity Consortium for Political and Social Research (ICPSR) within 24 months after the end date of the project, enabling other researchers in the field to analyze the data and publish from it following a 12-month embargo period. Specifically, we will be self-publishing the data through the openICPSR research data-sharing service (www.openicpsr.org), which assigns a persistent DOI and DDI-compliant metadata. This will enable independent reanalysis, verification, and secondary research.

We will submit de-identified IPD data and associated documentation to the Interuniversity Consortium for Political and Social Research (ICPSR) within 24 months after the end date of the project, enabling other researchers in the field to analyze the data and publish from it following a 12-month embargo period.

We will be self-publishing the data through the openICPSR research data-sharing service (www.openicpsr.org) which is accessible to anyone, as it is a publicly available dataset. The dataset will be publicly accessible upon embargo expiration. Users will be required to cite the dataset and adhere to ethical use standards. If the repository requires a click-through data-use statement, we will enable it to reinforce responsible use.

At least one research staff masked to group assignment at each of the 4 research sites.

Primary Investigators will be masked unless a situation arises during data collection that requires them to know which group a participant was assigned to.

The project statistician/Co-I will be masked to organization and individual participants and complete randomization using a random number generator. Each community service organization will be assigned a letter (A to H) to maintain masking.