Speed limits in many towns and cities should be reduced to 20mph, say the government's road safety advisers.
Their report claims a default speed of 20mph in built-up areas will help halve the number of deaths on Britain's roads within the next few years.
The study also called for greater enforcement of 20mph zones through a new generation of speed cameras.
The devices measure a driver's speed over a certain distance and should be a priority for the Home Office, it says.
The cameras are undergoing trials and still awaiting government approval for use in 20mph zones.
Robert Gifford, executive director of the Parliamentary Advisory Council for Transport Safety (Pacts) which produced the report, told BBC Radio 4's Today programme that reducing speed limits in towns would help save lives.
He said a survey by the Transport Research Laboratory of 20mph zones across the UK and in other European countries found child road accidents fell by 67%, cyclist accidents by 29% and traffic flow by 27%.
"These do work," he said. "People were thinking 'I could actually make that journey on foot, on my bicycle because the road feels safer as the remaining traffic is going more slowly.'
"What you get is more walking, more cycling, fewer people being killed or injured and the environment benefits."
Richard Curedon, from the Transport Research Laboratory, told the BBC cutting the speed limit would dramatically reduce the number of fatalities.
"Twenty miles an hour does seem so slow but simple physics are that if you're driving at that speed you can hopefully avoid the crash, which at 30 you're going to have," he said.
But Nigel Humphries, from the Association of British Drivers, said the move could be counter-productive with drivers concentrating more on their speedometers than the road and pedestrians lulled into a false sense of security.
"All you achieve by making people drive down the road looking at their speedometer is 10 times as many deaths and that's before you cause more accidents because people aren't looking where they're going".
Paul Smith, founder of Safespeed.org.uk, said the policymakers had missed a "golden opportunity".
"We don't need more regulation," he said. "We don't need more speed management.
"These policies have failed in spades. We need better drivers through education, information, and above all improved road safety culture."
The Pacts report, called Beyond 2010 - a holistic approach to road safety in Great Britain, also recommends that all new residential developments should be subject to a "pint of milk test".
This is whether a resident can reach a shop to buy a pint of milk in under 10 minutes without using a vehicle.
In the UK there are currently around 3,200 road deaths annually, compared with more than 7,000 a year in the 1960s.
This improvement is due to a number of factors, including seatbelts, improved car design, the breathalyser and traffic-calming measures.
The government has a target of reducing deaths and serious injuries on the roads by 40% by 2010 compared with the average figure for the mid-1990s.
Mr Gifford added: "Improving road safety is not an academic exercise. Deaths on our roads are preventable occurrences where society could and should do more to prevent them.
"Every year, the inhabitants of a town the size of Nottingham or Belfast are killed or injured on our roads. This report highlights the actions that need to be taken to reduce this level of death and injury."
But Daniel Moylan, deputy leader of the London borough of Kensington and Chelsea, told the BBC that the way to reduce speeds was to re-design the roads with fewer rules to engender a culture where people looked out for each other.
"This is a very national top-down approach that's being put forward," he said.
"Our roads are mostly run by local highways authorities and they need more autonomy and more encouragement to experiment with different means to improve accident statistics."