The Government's proposals to ease congestion on roads come as major motorways are already carrying more vehicles than their designed capacity, and heavy goods traffic is forecast to rise by almost 40 per cent between 1992 and 2002.
Amid concern over the attendant hazards of pollution and accidents, there are increasing calls for alternatives to road freight.
The debate has focused on rail transport, but Napier University's transport research institute is investigating another option: the sea.
Shipping has been largely ignored because it is assumed to be slow and costly despite the Royal Commission on Environmental Pollution suggesting the option of freight ferry services in 1994.
"There has been tremendous research on rail and very little on sophisticated sea transport," said lecturer Alf Baird.
He acknowledges that speed is a key consideration. Coastal ferries in the United Kingdom would offer no advantage in terms of distance, and conventional ferries would take twice as long as road haulage.
"For the UK coastal routes it appears that only high-speed freight ferries could effectively compete with road," he said.
Such ferries are already in service and shipyards are promoting new ferry designs aimed purely at carrying freight.
"There are other factors which make coastal shipping problematic, such as trade imbalances, a lot of traffic moving in one direction,"Mr Baird said.
"On the basis of existing goods flows between Scotland and England, we've looked at short corridors between the Clyde and the Mersey, and Rosyth to Harwich and Teesport."
Mr Baird's research shows that a high-speed ferry shuttle service with two or three sailings a day could match road haulage in terms of time.
Cut-throat competition between haulage companies means sea transport would need a subsidy to compete on cost, although ferries would become increasingly competitive if road costs increase through tolls or higher lorry taxes.
"But it's not just about cost," said Mr Baird.
"Sea transport could take 15 trucks out of every 100 on the trunk roads. And water is a free highway with an infinitecapacity."