Changes could be brought in at a number of motorway junctions across England after a car drove the wrong way down the carriageway killing three people.
Driver John Norton, 80, and passenger Olive Howard, 87, from High Wycombe, died when their Subaru towing a caravan crashed on the M40 in Oxfordshire.
The driver of a Mondeo, Stuart Richards, 32, from Stockport, Greater Manchester, also died in the collision.
Highways England said it was now reviewing "high risk" junctions.
The accident happened between junction 6 and junction 8A on 15 October.
Highways England said it was looking to introduce measures such as no entry signs or streetlights and to improve road markings.
A spokesman said: "Safety is our first priority and we monitor our network for locations with a high risk of wrong-way driving.
"We're actively reviewing [this] in light of the recent M40 incident. We are also undertaking wider international research examining the effectiveness of mitigation measures."
Sites where work has been undertaken or is planned:
- The A3 near Queen Elizabeth Country Park Visitor Centre
- The A5 at the M54 Junction 7
- The A1 between Clifton and Stannington
- The A1(M) between junction 4 and junction 5
- M25 on the west side of Clacket Lane Motorway Services Area
The Subaru was involved in another collision five days before the fatal crash.
Thames Valley Police said it had made a mandatory referral to the police watchdog in relation to the fatal collision "due to previous police contact".
Mr Richards was in the Army for nine years, serving as an engineer and safety officer in Iraq, Afghanistan and Jordan.
After leaving he worked as a health and safety adviser for Persimmon Homes.