Portsmouth is set to become the first in the UK to introduce a blanket 20mph traffic speed limit.
Portsmouth will introduce a blanket 20mph speed limit
Residential areas in the city will see the current 30mph speed limit reduced to 20mph by the end of 2008.
The city council will spend £475,000 introducing the scheme in six new zones over the next two years.
Approving the decision, Portsmouth City Council's road chief, Councillor Alex Bentley, said the move would reduce the risk of accidents and pollution.
But the decision has been criticised by the Association of British Drivers as being reactive rather than proactive.
The ABD's director of policy, Mark McArthur-Christie, said: "To use a blanket speed limit is a bit like the NHS saying we'll only issue plasters.
"There is no debate about the fact that in areas of high density the lower your speed limit needs to be.
"But if you put in a large number of 20mph speed limits where the natural speed limit is higher you end up with a dangerous situation where drivers spend more time concentrating on the limit rather than concentrating on the road."
Every road in Portsmouth will be covered by the new blanket Traffic Regulation Order apart from London Road, Northern Parade, Mile End Road, Eastern Road and the seafront.
'Must do better'
Mr Bentley said: "Serious injury accidents on Portsmouth's roads are falling, but we must do better.
"There is no doubt that the speed at which vehicles travel and the injuries sustained by someone in collision with a vehicle are directly related.
"I cannot think that any right-minded person would have a problem with this proposal, particularly as on a great number of our roads it's actually quite difficult to drive more than 20mph anyway."
New 20mph signs will be installed in three zones - North East, Central West and South East - next year with another three zones following suit in 2008.
The six new zones are:
North East - Drayton, Farlington, Cosham East, Highbury, Anchorage Park North West - Paulsgrove, Wymering and Cosham West Central East - Fratton, Copnor, Baffins, part of Buckland Central West - Tipner, Stamshaw, North End, Hilsea, part of Buckland South East - Central Southsea, East Southsea, Eastney, Milton South West - Somestown, Charles Dickens, Portsea, Old Portsmouth, West Southsea