Roadside safety inspections have been an important component of federally supported programs to improve motor carrier safety. The inspection selection system (ISS) and its successor, ISS-2, were designed to help roadside inspectors target the vehicles of Interstate carriers with the worst past safety performance. ISS was used as a starting point for developing an intrastate ISS for Wisconsin. Logistics regression was used to identify the relevant independent variables. The logit model estimates the probability that a vehicle will be found to have an out-of-service (OOS) safety violation. An alternative to the logit model, a simple direct-estimation technique that uses the total OOS rate for a motor carrier, was found to produce the highest success rates in predicting inspections that result in an OOS violation. The model can be implemented as a field inspection tool and as a means to generate a list of intrastate carriers ranked by their historical OOS violation record.