Trial Outcomes & Findings for Impacts of Subsidized Ridesharing on Drunk Driving, Alcohol Consumption, and Mobility (NCT NCT04949711)
NCT ID: NCT04949711
Last Updated: 2026-04-17
Results Overview
Participants will provide two self-reported measures of impaired driving by indicating whether they "drove after drinking any alcohol" (driving after drinking) and "drove after drinking too much alcohol to drive safely" (driving while intoxicated) for each day during the previous 7 days. Data is recorded at baseline and at 1 week follow-up.
COMPLETED
NA
7034 participants
At 1 week follow-up from baseline
2026-04-17
Participant Flow
Participants were recruited via social media advertisements in eligible, randomly selected cities across the United States. While the cities were selected based on shared criteria, the study design is a two-arm, parallel-group randomized controlled trial where the individual is the unit of randomization, and it is not a cluster-randomized trial. To increase the likelihood of balance within cities, we utilized stratified randomization, using the city of residence as the stratification factor.
Participants enrolled but lost to follow-up before the pre-intervention survey were not assigned to a study arm. 5856 out of 7034 were randomized to a study arm.
Participant milestones
| Measure |
Intervention
Participants will be asked to complete 3 surveys (enrollment survey, pre-intervention survey, and post-intervention survey) over 2 weeks to collect information on their alcohol use and about themselves, and receive ridesharing vouchers.
|
Control
Participants will be asked to complete 3 surveys (enrollment survey, pre-intervention survey, and post-intervention survey) over 2 weeks to collect information on their alcohol use and about themselves, and receive an online shopping voucher.
|
|---|---|---|
|
Overall Study
STARTED
|
2921
|
2935
|
|
Overall Study
GPS Sub-sample
|
117
|
113
|
|
Overall Study
COMPLETED
|
2736
|
2751
|
|
Overall Study
NOT COMPLETED
|
185
|
184
|
Reasons for withdrawal
| Measure |
Intervention
Participants will be asked to complete 3 surveys (enrollment survey, pre-intervention survey, and post-intervention survey) over 2 weeks to collect information on their alcohol use and about themselves, and receive ridesharing vouchers.
|
Control
Participants will be asked to complete 3 surveys (enrollment survey, pre-intervention survey, and post-intervention survey) over 2 weeks to collect information on their alcohol use and about themselves, and receive an online shopping voucher.
|
|---|---|---|
|
Overall Study
Lost to Follow-up
|
185
|
184
|
Baseline Characteristics
Impacts of Subsidized Ridesharing on Drunk Driving, Alcohol Consumption, and Mobility
Baseline characteristics by cohort
| Measure |
Intervention
n=2921 Participants
Participants will be asked to complete 3 surveys (enrollment survey, pre-intervention survey, and post-intervention survey) over 2 weeks to collect information on their alcohol use and about themselves, and receive ridesharing vouchers.
|
Control
n=2935 Participants
Participants will be asked to complete 3 surveys (enrollment survey, pre-intervention survey, and post-intervention survey) over 2 weeks to collect information on their alcohol use and about themselves, and receive an online shopping voucher.
|
Total
n=5856 Participants
Total of all reporting groups
|
|---|---|---|---|
|
Age, Continuous
|
36 years
STANDARD_DEVIATION 14 • n=130 Participants
|
36 years
STANDARD_DEVIATION 13 • n=132 Participants
|
36 years
STANDARD_DEVIATION 14 • n=130 Participants
|
|
Sex/Gender, Customized
Sex/Gender · Female
|
2001 Participants
n=130 Participants
|
1982 Participants
n=132 Participants
|
3983 Participants
n=130 Participants
|
|
Sex/Gender, Customized
Sex/Gender · Male
|
899 Participants
n=130 Participants
|
924 Participants
n=132 Participants
|
1823 Participants
n=130 Participants
|
|
Sex/Gender, Customized
Sex/Gender · Other
|
21 Participants
n=130 Participants
|
29 Participants
n=132 Participants
|
50 Participants
n=130 Participants
|
|
Race (NIH/OMB)
American Indian or Alaska Native
|
29 Participants
n=130 Participants
|
22 Participants
n=132 Participants
|
51 Participants
n=130 Participants
|
|
Race (NIH/OMB)
Asian
|
277 Participants
n=130 Participants
|
286 Participants
n=132 Participants
|
563 Participants
n=130 Participants
|
|
Race (NIH/OMB)
Native Hawaiian or Other Pacific Islander
|
6 Participants
n=130 Participants
|
12 Participants
n=132 Participants
|
18 Participants
n=130 Participants
|
|
Race (NIH/OMB)
Black or African American
|
241 Participants
n=130 Participants
|
278 Participants
n=132 Participants
|
519 Participants
n=130 Participants
|
|
Race (NIH/OMB)
White
|
2081 Participants
n=130 Participants
|
2082 Participants
n=132 Participants
|
4163 Participants
n=130 Participants
|
|
Race (NIH/OMB)
More than one race
|
173 Participants
n=130 Participants
|
131 Participants
n=132 Participants
|
304 Participants
n=130 Participants
|
|
Race (NIH/OMB)
Unknown or Not Reported
|
114 Participants
n=130 Participants
|
124 Participants
n=132 Participants
|
238 Participants
n=130 Participants
|
|
Ethnicity
Hispanic or Latino
|
385 Participants
n=130 Participants
|
375 Participants
n=132 Participants
|
760 Participants
n=130 Participants
|
|
Ethnicity
Not Hispanic or Latino
|
2471 Participants
n=130 Participants
|
2498 Participants
n=132 Participants
|
4969 Participants
n=130 Participants
|
|
Ethnicity
Unknown or Not Reported
|
65 Participants
n=130 Participants
|
62 Participants
n=132 Participants
|
127 Participants
n=130 Participants
|
PRIMARY outcome
Timeframe: At 1 week follow-up from baselinePopulation: Enrolled participants who were lost to follow-up between the pre-intervention and post-intervention surveys were not included in the outcome measure. Additionally, participants who elected not to respond to the survey question regarding this measure were not included in the outcome measure.
Participants will provide two self-reported measures of impaired driving by indicating whether they "drove after drinking any alcohol" (driving after drinking) and "drove after drinking too much alcohol to drive safely" (driving while intoxicated) for each day during the previous 7 days. Data is recorded at baseline and at 1 week follow-up.
Outcome measures
| Measure |
Intervention
n=2441 Participants
Participants will be asked to complete 3 surveys (enrollment survey, pre-intervention survey, and post-intervention survey) over 2 weeks to collect information on their alcohol use and about themselves, and receive ridesharing vouchers.
|
Control
n=2467 Participants
Participants will be asked to complete 3 surveys (enrollment survey, pre-intervention survey, and post-intervention survey) over 2 weeks to collect information on their alcohol use and about themselves, and receive an online shopping voucher.
|
|---|---|---|
|
Number of Participants Involved in Alcohol Impaired Driving Incidents
Driving after drinking
|
771 Participants
|
802 Participants
|
|
Number of Participants Involved in Alcohol Impaired Driving Incidents
No driving after drinking
|
1670 Participants
|
1665 Participants
|
SECONDARY outcome
Timeframe: Baseline, 1 week follow-upPopulation: Enrolled participants who were lost to follow-up between the pre-intervention and post-intervention surveys were not included in the outcome measure. Additionally, participants who elected not to respond to the survey question regarding this measure were not included in the outcome measure.
Participants will be asked to state the number of drinks consumed on each day for the 7 previous days, and their responses will be used to calculate the frequency (defined as the number of drinking days) of drinking.
Outcome measures
| Measure |
Intervention
n=2921 Participants
Participants will be asked to complete 3 surveys (enrollment survey, pre-intervention survey, and post-intervention survey) over 2 weeks to collect information on their alcohol use and about themselves, and receive ridesharing vouchers.
|
Control
n=2935 Participants
Participants will be asked to complete 3 surveys (enrollment survey, pre-intervention survey, and post-intervention survey) over 2 weeks to collect information on their alcohol use and about themselves, and receive an online shopping voucher.
|
|---|---|---|
|
Change in Number of Days in Alcohol Consumption
Baseline
|
3.21 number of drinking days
Standard Deviation 2.05
|
3.07 number of drinking days
Standard Deviation 2.05
|
|
Change in Number of Days in Alcohol Consumption
1 week follow-up
|
2.83 number of drinking days
Standard Deviation 2.14
|
2.82 number of drinking days
Standard Deviation 2.14
|
SECONDARY outcome
Timeframe: Day 3 to Day 17 of studyPopulation: Enrolled participants who were lost to follow-up were not included in the outcome measure. Additionally, participants without valid GPS data were not included in the outcome measure. Only 117 out of 2921 in the Intervention Arm and 113 out of 2935 in the Control Arm were included in the analysis.
Participants enrolled in the GPS sub-sample will be tracked and GPS records will be used to measure exposure to alcohol outlets and mobility.
Outcome measures
| Measure |
Intervention
n=117 Participants
Participants will be asked to complete 3 surveys (enrollment survey, pre-intervention survey, and post-intervention survey) over 2 weeks to collect information on their alcohol use and about themselves, and receive ridesharing vouchers.
|
Control
n=113 Participants
Participants will be asked to complete 3 surveys (enrollment survey, pre-intervention survey, and post-intervention survey) over 2 weeks to collect information on their alcohol use and about themselves, and receive an online shopping voucher.
|
|---|---|---|
|
Average Number of Trips to Alcohol Outlets
|
1.12 Number of trips to alcohol outlets
Standard Deviation 2.10
|
0.92 Number of trips to alcohol outlets
Standard Deviation 1.55
|
SECONDARY outcome
Timeframe: Day 3 to Day 17 of studyPopulation: Enrolled participants who were lost to follow-up were not included in the outcome measure. Additionally, participants without valid GPS data were not included in the outcome measure. Only 117 out of 2921 in the Intervention Arm and 113 out of 2935 in the Control Arm were included in the analysis.
Participants enrolled in the GPS sub-sample will be tracked and GPS records will be used measure exposure to alcohol outlets and mobility.
Outcome measures
| Measure |
Intervention
n=117 Participants
Participants will be asked to complete 3 surveys (enrollment survey, pre-intervention survey, and post-intervention survey) over 2 weeks to collect information on their alcohol use and about themselves, and receive ridesharing vouchers.
|
Control
n=113 Participants
Participants will be asked to complete 3 surveys (enrollment survey, pre-intervention survey, and post-intervention survey) over 2 weeks to collect information on their alcohol use and about themselves, and receive an online shopping voucher.
|
|---|---|---|
|
Average Duration of Trips to Alcohol Outlets
|
1.12 minutes
Standard Deviation 2.10
|
0.92 minutes
Standard Deviation 1.55
|
SECONDARY outcome
Timeframe: Baseline, 1 week follow-upPopulation: Enrolled participants lost to follow-up at each timepoint are not included in the outcome measure. Additionally, participants who elected not to respond to the survey question regarding this measure were not included in the outcome measure. Only 2729 out of 2921 in the Intervention Arm and 2747 out of 2935 in the Control Arm were included in the analysis.
Select questions related to The Drinker Inventory of Consequences (DrInC), a measure of alcohol-related consequences on which higher scores reflect greater alcohol consequences. (Score range: 0-8)
Outcome measures
| Measure |
Intervention
n=2729 Participants
Participants will be asked to complete 3 surveys (enrollment survey, pre-intervention survey, and post-intervention survey) over 2 weeks to collect information on their alcohol use and about themselves, and receive ridesharing vouchers.
|
Control
n=2747 Participants
Participants will be asked to complete 3 surveys (enrollment survey, pre-intervention survey, and post-intervention survey) over 2 weeks to collect information on their alcohol use and about themselves, and receive an online shopping voucher.
|
|---|---|---|
|
Change in The Drinker Inventory of Consequences Score
Baseline
|
0.90 score on a scale
Standard Deviation 1.38
|
0.87 score on a scale
Standard Deviation 1.41
|
|
Change in The Drinker Inventory of Consequences Score
1 week follow-up
|
0.70 score on a scale
Standard Deviation 1.25
|
0.68 score on a scale
Standard Deviation 1.23
|
Adverse Events
Intervention
Control
Serious adverse events
Adverse event data not reported
Other adverse events
Adverse event data not reported
Additional Information
Results disclosure agreements
- Principal investigator is a sponsor employee
- Publication restrictions are in place