Speed limits will be cut on dozens of key roads in Oxfordshire, despite the reservations of police.
At a meeting earlier, county councillors agreed to cut the limit on 48 A and B roads to improve safety.
Before the meeting police objected to many of the changes, including reducing the limit on a section of the A40 at Oxford from 70mph to 50mph.
A council report shows Thames Valley officers believe there will be "little or no compliance" from motorists.
20mph zones introduced
Councillors said they considered the police objections to the changes, which were included in the report written by transport experts.
The report followed a year-long study into road safety in the county.
At the meeting councillors also agreed to increase the speed limits on five stretches. The changes on the 53 roads are likely to be made after March.
Last year the number of road deaths in Oxfordshire fell from 48 to 30, the lowest level since records began 35 years ago.
In August 2009 the council introduced 20mph speed limits on many residential roads in Oxford despite objections by police.