The Royal Ulster Constabulary (RUC) Traffic Branch was created in 1930 to police the rising number of motor vehicles on Northern Ireland roads. The branch was established in Belfast and consisted of twelve men patrolling the roads on 498 CC Triumph motorbikes with sidecars. The new Road Traffic Act gave constables the right to stop, penalise or arrest without warrant, drivers who were guilty of motoring offences such as speeding, reckless, dangerous or careless driving, driving while under the influence of drink or drugs, driving without a licence or ignoring a traffic sign.

Car ownership in Great Britain had rapidly increased since the previous 1903 Motor Car Act. In 1905 there were 15,895 private car licences, this figure had increased to 1,760,533 by 1930. During the same period, the number of traffic accidents increased and the death toll on Britain's roads had risen to 7,305. The 1929 Royal Commission of Transport investigated safety on the roads and identified a number of measures for improved control of traffic. These recommendations were enacted in the Road Traffic Act 1930 and enforced by police traffic divisions across the UK.