Converting some rail routes into busways on which express coaches would run could chop 40% off commuter fares, according to a report from a think-tank.
Allowing busways on some commuter routes into London could also mean more passengers getting a seat at peak times, the report from the Institute of Economic Affairs (IEA) said.
The IEA also said travel times would be the same, if not shorter through the creation of a busway system.
The report reckoned that converting commuter railways into busways would bring about cheaper fares for passengers, as operating and infrastructure costs would be much lower.
The IEA argued that although the initial cost of conversion would be substantial, adding new rail capacity and continuing rail subsidies would be far more expensive.
Entitled Paving over the tracks: A better use of Britain's railways?, the report envisaged 150 express coaches each seating 75 people operating on commuter rail routes in the morning rush hour.
The report's authors said current government spending on the rail network "costs the taxpayer £6 billion a year and benefits rail companies at the expense of passengers, who often receive poor value for money".
The report added: "Heavy subsidies, rigid state control and powerful interest groups have distorted the industry, resulting in alternative modes of transport being ignored despite their often huge potential for improved capacity and cost reduction."
The authors said Bus Rapid Transit schemes in Latin America and Asia had been successful.
In the UK, there is already a 16-mile Cambridgeshire Guided Busway which uses old rail routes to link Cambridge, Huntingdon and St Ives.
The report's author and the IEA's head of transport, Dr Richard Wellings, said: "Ongoing interference by politicians in the rail industry has led to everyone getting a raw deal.
"Passengers face increasingly expensive fares only to fight their way on to trains during peak times and taxpayers continue to prop up an industry whose importance to the country is disproportionally small relative to the level of resources it receives."
He went on: "Adopting more efficient methods of transport could offer considerable benefits to passengers and the taxpayer alike.
"But only when the sector is liberalised from rigid state control will we see such alternatives being seriously considered."
A spokesman for the Rail Delivery Group, which represents train operators and Network Rail (NR), said: "The railway brings 2.5 million people a day into Britain's biggest cities and towns and rail freight helps to keep the lights on and fill supermarket shelves.
"The Government's sustained investment in rail is a recognition of the crucial role it plays in underpinning jobs and driving economic growth."
He went on: "Phenomenal growth in passenger numbers means that operators and NR now generate some £9 billion of income which covers the day-to-day running of the railway.
"The £4 billion that government invests through NR supports its capital programme to improve rail infrastructure, creating more capacity and helping to deliver faster, more reliable journeys."
Alternatively they could be made buses only during the peak.
