Marshall Haynes, Liam Hastings and Josh Bartlett died in the crash

The work on the Oxford Eastern Bypass barrier between Kiln Lane and Horspath Driftway will begin on 30 January.

A permanent 50mph speed limit is also to be introduced along the route by Oxfordshire County Council.

A mother faces four death by dangerous driving charges after the crash on 28 May, which happened as she took her son and friends on a birthday outing.

Howard Hillsdon was a student at Oxford Brookes University

Those who died were 13-year-olds Josh Bartlett, Liam Hastings and Marshall Haynes and 21-year-old Howard Hillsdon.

Mr Hillsdon was travelling in another car when the crash happened.

Angela Dublin, 45, a nurse, of London Road, Headington, Oxford, was charged after the accident left her in hospital together with her 13-year-old son whose birthday it was.

Work on introducing the new barrier will take nine weeks and one lane in both direction will be closed for safety reasons.

Councillor David Robertson, the county council's cabinet member for transport, said: "The barrier will reduce the possibility of future cross-over accidents on that part of the bypass.

"It has to be pointed out that we have many requests for safety measures following serious accidents.

"We cannot meet all of these requests even though sometimes people lose their lives. We need to concentrate on what will best reduce casualties."