The alliances say road must be put ahead of rail in investment terms
Motorists are getting a "raw deal" from the government, which is investing over 10 times more in rail than road travel, according to two campaign groups.
The Taxpayers' Alliance and the Drivers' Alliance say that spending per 1,000 passenger kilometres travelled is £138.66 for rail and £11.11 for road.
They say drivers pay "huge amounts of tax" and deserve to have road investment prioritised.
But rail group Greengauge21 said funding new roads was "a mug's game".
The Taxpayers' Alliance, which campaigns for lower taxes and greater government efficiency, is working in partnership with the drivers' group, which is against road pricing and "excessive" motoring taxes.
They based their calculation on total spending in 2007/08 of £8.2bn on rail and £8.3bn on roads.
While those two figures are roughly similar, campaigners say 59 billion passenger kilometres were travelled by rail in that period, compared with 749 billion by road.
Overall, they argue motorists paid £30.3bn in fuel duty and Vehicle Excise Duty in 2007/08 - £18.4bn more than was spent on improving the road network and offsetting the cost of road transport pollution combined.
Jennifer Dunn, policy analyst with the Drivers' Alliance and the Taxpayers' Alliance, said: "Motorists are getting a really raw deal thanks to the government's misguided transport policy.
"Drivers suffer a double whammy - they pay huge amounts of tax, and only receive a disproportionately small share of transport spending."
Drivers' Alliance chief executive Peter Roberts said road spending must be prioritised if congestion was to be tackled.
"Spending vast sums of drivers' taxes on extravagant rail projects will not address the immediate transport problems we have in the UK."
But Jim Steer, from Greengauge21, which promotes the development of a high-speed rail network in the UK, said roads were rightly second in terms of spending.
"Rail use has been growing faster than car use over the last 10 years or so," he told the BBC News website.
"You might say that's precisely because we don't invest as much in roads, but the truth of the matter is that it's now clear that it's a mug's game to try to invest enough in the road network to meet rising demand. You just can't do it.
"It's perfectly possible to get a good rail system in this country - it's an achievable thing - but to keep trying to expand the road network is impractical."
A spokesman for Network Rail described the alliances' figures as "highly misleading".
"Motorists should welcome investment in Britain's railways as it is one of the best ways to reduce congestion on the roads," he added.
Meanwhile, the Department for Transport said in a statement: "We must both tackle congestion and provide a safe, reliable and sustainable road network for the 21st Century.
"But to beat congestion we must also provide high-quality public transport and we make no apology for investing in rail, which is having clear benefits."