A fog sensor will be installed on the M40 two years after a 33-vehicle crash killed a man and left dozens injured.
The new sensor will be added to a stretch of the motorway near junction 9, a popular commuter route for drivers from the High Wycombe area.
Highways England said it would release more details on when it would be put in place in the coming weeks.
The announcement comes two years after a man was killed and more were seriously injured in a crash on the motorway near Bicester.
Police said at the time that fog had played a “major part” in the crash on February 14, 2015, which left Robert Pilott, 64, dead and that it had been the single largest collision the force had dealt with for many years, involving more than 50 motorists and passengers.
Highways England spokesman Jack Tappin said: “Driver safety is a top priority for Highways England across all of our roads.
“We are committed to installing a new fog sensor on the M40 near junction 9, which we believe will improve driver safety.
“We are currently in the final stages of agreeing this work and will look to deliver it soon.”
An inquest into the death of Mr Pilott in September 2015 heard how there had been no fog sensor at that road and coroner Darren Salter promised to write to Highways England about the issue.
Fog was also a factor after an Oxford Bus Company coach overturned on the M40 near Thame in December.
The only fog detector on the M40 currently is at junction 15 near Warwick.
The devices alert highway staff to fog, enabling them to trigger electronic warning signs.