Dorset Police and National Highways carried out a joint road safety operation using an unmarked HGV.
During the week-long initiative, 171 motorists were issued with traffic offence reports.
Offences included mobile phone use, not wearing seatbelts, careless driving and driving without insurance.
Three people were arrested on suspicion of drink or drug driving offences and four vehicles were seized.
Police say the operation forms part of ongoing efforts to reduce deaths and serious injuries on Dorset’s roads.