Firstly, the roading lobby includes road users who provide all of the money in the Land Transport Fund. Not surprisingly they can get very uppitty if they find that their roads are falling apart because their road taxes are being siphoned off into a government slush fund. Essentially governments pushed their cash-cow approach to roads too far in the 1940s and road users revolted in the mid-50s. Hence the roading "lobby" took back what was rightly theirs.

It has never been possible to build or improve railways from cash flow because, unlike roads, it is not possible to build or improve just a few hundred metres at a time, or even a few kilometres. Typically railways need tens of kilometres to be done in one go. This became a major problem after the second world war when the railways had to compete for public works loans with state housing and huge hydro-electric schemes. However, this problem was hidden until 1954 by the simple expedient of spending half the petrol tax on railways capital works. Between 1954 and 1973 all of the petrol tax was paid into the National Road Fund. This change was triggered by the waterfront dispute disrupting caostal shipping and revealing the fact most of the highway system couldn't carry fully laden trucks because more than three-quarters of the bridges were weight restricted. Coming so soon after the second world war this was seen as a serious threat to national defence as well as a serious threat to economic development. The Roading Investigation Comittee identified the effects of inflation as the major cause of the problem and recommended that the government double the petrol tax, heavy vehicle fees and registration fees to cover inflation since the introduction of these fees in the 1920s. The committee pointed out that road users would resist these increases because half the petrol tax was being used for general government revenue and this was a huge psychological barrier to the motorist's willingness to pay more money for better roads. The government accepted this argument and, by returning all of the petrol tax to the road fund, was able to gain the support of road users for doubling the all the other fees and to also increase the petrol tax by 25% (an additional 15 cents per litre). Unfortunately subsequent governments have pandered to the short term electoral advantages of not increasing the petrol tax in line with inflation. Worse, by reintroducing a Crown petrol tax they have recreated the psychological resistance to paying the real price of creating a modern land transport system.