The US government will encourage private-sector investment in new ports, railways, airports and bridges but will not raise federal fuel taxes or restructure financing for existing roads, according to the transport secretary.

Improved vehicle efficiency and falling real-terms fuel tax rates risk curbing budgets for the nation’s road maintenance programmes

In an interview with the Financial Times, Ray LaHood brushed aside calls from many states and transport economists for a fundamental review of the level and means of taxing road use in the US.