Despite efforts by the Kenyan government to enhance road safety, Kenya ranks among the top countries with high road fatality rates. Therefore, this study examined the effects of police roadblock checks on reduction of road accidents along the Salgaa- Mau Summit Highway in Nakuru County. This study was grounded on the Systems Theory and the Deterrence Theory. The study used a descriptive research design. Stratified and simple random sampling techniques were used to identify and select 103 respondents from a population of 302 respondents consisting of 60 traffic police officers; 8 NTSA officers; 218 public service vehicle drivers; and 12 passengers. Four (4) senior officers from traffic police and NTSA were selected as key informants using purposive sampling. Questionnaires were used to collect data from traffic police officers, drivers, passengers and NTSA officers while interviews were used to collect data from senior officers. The SPSS (version 23) was used to conduct descriptive and regression analysis. Qualitative data were analysed using thematic analysis. This study established that police roadblock checks have a significant effect on reduction of road accidents as it accounts for 54.2% variation in road accidents. Results of regression analysis established that Roadblock Checks have a significant effect on reduction of road accidents (β3= - 0.526; P=0.001). The study also found out that police manning the roadblocks mitigate risks of accidents by detaining drunk and speeding drivers, removing non-compliant vehicles; enhancing compliance with road safety regulations; and arresting those violating traffic laws. However, the definitiveness of the police roadblocks has encouraged reckless driving outside the monitored zone, the difficulty of decelerating down the sloppy 11km stretch of the Highway and corruption among some of the traffic police officers have affected the effectiveness of roadblock checks in reducing road accidents.