(27)Sensors installed on vehicles are already used to detect anomalies on emissions and trigger related repairs through the on-board diagnostic (OBD) system. The OBD system currently in use, however, does not accurately detect the malfunctions in a timely manner and does not sufficiently urge repairs on time. As a result, it is possible that vehicles have much higher pollutant emissions than allowed. The sensors used until now for OBD could also be used to monitor and control the exhaust emission performance of the vehicles on a continuous basis via an OBM system. The OBM system will also warn the user to perform repairs of the engine or the pollution control systems when such repairs are needed. It is therefore appropriate to require that such a system is installed and that its technical requirements are regulated. The measures implied by those systems should not lead to road safety being endangered.