Work will begin on Monday to build a crash barrier where three teenagers and a motorist were killed on Oxford's Eastern Bypass.

Oxfordshire County Council will install a £600,000 concrete crash barrier along the bypass between Kiln Lane and Horspath Driftway following overwhelming public pressure.

Three 13-year-olds, Josh Bartlett, Liam Hastings and Marshall Haynes, and lifeguard Howard Hillsdon, 21, died when a car veered across the grass central reservation into oncoming traffic in May last year.

Work is expected to last nine weeks and cause delays for motorists using the bypass.

Last night, Josh's mother Jane Barber, of Blackbird Leys, welcomed the start of work.

"I'm very glad it's going in but I wish the council had listened to people before and then Josh would have still been here," she said.

"But it's going up now and hopefully it will never happen to anyone else's child.

"It has been an issue in the past and families have complained before and brought it to the attention of everyone but it wasn't listened to.

"It's taken the loss of my son and other children for it to happen and it should have been done earlier.

"Each day is harder than ever, the only thing that keeps me going is my other children."

A petition calling for a barrier was signed by more than 2,500 people and handed over to highways chiefs days after the crash.

The campaign was also backed by the Oxford Mail, Oxford East MP Andrew Smith and Adrian Bull, of Littlemore, who was left paralysed after a similar 'cross-over' accident on the same spot five years ago.

The concrete barrier was chosen by Oxfordshire County Council ahead of a cheaper metal and wire barrier because it gives greater protection for vehicles, a spokesman said.

The barrier will have shallow foundations due to high voltage cables running underneath the central reservation and three gaps after ancient rights of way were found running across the bypass.

Speed on the bypass will be limited to 40mph and traffic reduced to using one lane in either direction while it is being built.

Motorists using Oxford's Eastern Bypass are advised to expect delays for the next nine weeks.

David Robertson, council county member for transport, said: "We are acutely aware that there are lots of roadworks on the go at the moment and that people often feel quite frustrated.

"However, they are all essential and will benefit the people of Oxfordshire in the long run. In this particular instance, I am sure motorists will welcome these safety improve- ments."

When the new barrier is finished in April, a 50mph limit will be imposed.