New Zealand had tended to be over-supplied with some types of transport facilities in the decade before the war. Road transport, while essential as a feeder service to the railways, tended also to offer facilities parallel to those already available by rail. In particular, the Railways Department had been severely affected by competition from the motor lorry. Transport licensing had been introduced in 1931, having for one of its objectives the prevention of excessive competition with the Railways Department. But, on routes where licensing did not prevent it, there was still considerable competition for the transport of passengers and goods right up to the outbreak of war.
The private motor car was also taking a considerable part of the passenger load which would otherwise have fallen on railways or buses. In the three years from 1936 to 1939 motor vehicle registrations had increased by a quarter. In particular, registrations of motor cars had increased by 42 per cent and registrations of heavy trucks by 32 per cent. In terms of the popularity of the motor car, New Zealand was second only to the United States of America, and the number of private motorists was increasing by about one-eighth in each year.
The rapid increase in numbers of motor vehicles not only created a demand for new and better roads but provided, through taxation on motor spirits, an expanding source of revenue for road building and maintenance.
Petrol imports had increased by one-fifth in the three pre-war years and, by 1939, made up 4 per cent by value of all New Zealand imports. All petrol for use on the roads had to be imported, whereas coal for railways locomotives could be mined in New Zealand. The greater relative importance of motor transport was increasing New Zealand's dependence on imports to supply the traction power for transport and, consequently, increasing the vulnerability of her transport system in the event of war. Fittingly, petrol rationing came into force the day war was declared.1
1 The Oil Fuel Emergency Regulations were gazetted as part of the Supply Control Emergency Regulations 1939, on 4 September 1939.