The road traffic safety factor is divided into three basic groups: human, vehicle, road (infrastructure). Technically defective, poorly maintained and technologically obsolete vehicles endanger road safety. The number of technically defective vehicles that are involved in traffic accidents, when checks are carried out by officers of traffic police, is 0.2%. Considering that 21.31% of vehicles are found to be defective by periodical technical inspections of vehicles (PTI), it is expected that the number of technically defective vehicles in daily traffic is considerably higher. By analyzing the data collected by PTI and comparing them with the data obtained during the conducted research “Inspection of the technical safety of vehicles involved in road traffic accidents with fatalities” the real state of the technical condition and safety of vehicles on the roads in the Republic of Croatia is presented here. Two-wheel vehicles (mopeds and motorcycles) represent a particularly risky group.