The A16, in Lincolnshire, was extended to Peterborough in 2010, after years of campaigning, delays and a public inquiry.
The speed enforcement cameras will be installed on the stretch of road between Spalding and Crowland.
John Siddle from the Lincolnshire Road Safety Partnership said some drivers were using the road like a race-track.
"Because everything is cut back and it is a very flat area of the county there are no fixed points to gauge distance and speed of other vehicles approaching," he said.
"People are going for overtakes at high speed and what we call injudicious overtakes - which means it's going to go wrong."
A similar scheme on the A15 near Lincoln saw two fixed cameras replaced with average speed checks with the number of drivers caught speeding dropping from an average of 175 a week to 17.
In the five years since the cameras went live on the A52 near Grantham, casualties have fallen by 55%.
The average speed system will be installed on an eight-mile stretch of the A16 from the junction with A1175 near Spalding and the roundabout south of Crowland.
August 2011 - 22-year-old man killed in head-on collision overtaking another car
January 2012 - 78-year-old woman killed when she pulled into the path of another car
November 2012 - 52-year-old man killed when hit by oncoming car overtaking a lorry
April 2012 - 58-year-old cyclist hit and killed
May 2013 - 22-year-old man walking on the road hit and killed
December 2013 - 23-year-old man walking at night hit and killed
March 2014 - 37-year-old motorcyclist killed in head on collision by a car overtaking a lorry
May 2015 - 80-year-old woman killed in three-car crash at a junction
A road which has seen eight deaths and 15 serious injuries in its first five years is to get average-speed cameras.