Speed cameras are to be used to enforce the change in the speed limit in Old Shoreham Road, Hove.
The Sussex Safer Roads Partnership said that mobile speed cameras were likely to go live in the week starting Monday 10 February.
The organisation said: “A new mobile speed enforcement site is to be established in Old Shoreham Road, Hove, near the cemetery, after motorists failed to heed a change in speed limit.
“The speed limit on the affected section of Old Shoreham Road changed to 30mph from 40mph in December 2011.
“However, average speeds along the road are approximately 36mph.”
The organisation said that 15 per cent of drivers were driving at or above 41.7mph – vastly in excess of the 30mph speed limit.
It said: “In the last three years, there has been a cluster of 13 collisions, resulting in 18 casualties, at the junctions of both Olive Road and Stapley Road.”
Operations manager Phil Henty said: “As anyone familiar with the Highway Code will know, a system of streetlights along a road indicates a 30mph limit unless signs direct motorists otherwise.
“This section of Old Shoreham Road has seen a number of collisions attributable to drivers travelling too fast at the Olive Road junction.
“Despite the speed limit being reduced to 30mph over two years ago, a significant number of motorists still choose to drive well in excess of 30mph.
“Our speed camera vehicle will be positioned on the central reservation and operators will be able to monitor traffic travelling in both directions.”
Equipment has been installed in the road to help monitor changes in driver behaviour after a vehicle-activated sign and a number of metal speed limit signs go live in the imminent future.
The safer roads partnership said: “In the past three years (collision data to the end of November 2013), there have been 13 collisions resulting in 18 casualties in the area monitored by the new Old Shoreham Road mobile speed camera.
“Of the 18 casualties, two resulted in serious injury. Of the total casualties, four were pedestrians, two were cyclists, two were children and three were OAPs.”
The safer roads partnership consists of Brighton and Hove City Council, Sussex Police, the Highways Agency, East Sussex Fire and Rescue Service, West Sussex Fire and Rescue, East Sussex County Council and West Sussex County Council.
