Colorado.

Methods	Longitudinal study.
Participants	Repeat offenders. 501 interlock participants and 349 did not installs.
Interventions	Offenders had to have applied for an Interlock Probationary Licence. Participation was voluntary. Sept 1998 ‐ Oct 2000.
Outcomes	Recidivism rates while the interlock was installed in the vehicle and for one year following the removal of the device.
Notes	Program managed by the Hearings Section of the Colorado Department of Revenue. Interlock applicants were older, had higher family income, were non‐hispanic whites and had at least a high school or equivalent education than non‐applicants. Quality assessment score 16/27
Risk of bias
Bias	Authors' judgement	Support for judgement
Allocation concealment?	Unclear risk	D ‐ Not used