Speed cameras are set to be installed on a dual carriageway at a cost of more than £1m.
The A30 Sherborne to Yeovil has one of the worst accident records in the county, with six fatalities and more than 60 casualties over a decade.
The cost is being covered by the Department for Transport and comes after repeated accidents and comments from the coroner for further action to be taken.
Sherborne councillor Jon Andrews said: “Given the deaths and serious injuries on the road, something needed to be done.”
Motorists have been recorded in excess of 100mph on the four-mile section at the Over Compton junction, even after the limit was reduced from 70 to 60mph.
Changes have also been made to the junction at Loscombe Corner to reduce potentially dangerous turns.
Dorchester independent councillor Les Fry, a former police inspector, said the stretch of road was a favourite with “car enthusiasts” and “boy-racers” and was ideally suited to average speed cameras.
Sherborne rural ward councillor Robin Legg also welcomed the cameras and said he had been shunted from behind on the road 40 years ago, writing his car off and leaving him with a neck injury.
Chickerell councillor Simon Clifford said on his first day as a trainee journalist he had been sent to interview the parents of a 10-year-old Over Compton girl who had died on the road.
“I’ve since retired and there are still fatalities on that stretch of road,” he said. “Let’s just get this done and make people safer.”
Mr Andrews said cameras would be “cost-effective when considered against the cost of lost and damaged lives”.
“The implementation is considered both necessary and proportionate,” he told Tuesday night’s Cabinet meeting.
