A new report says congestion on the M25 is so bad the region's economy is at risk and urgent action must be taken.
The report by Highways England found the stretch of motorway between the A3 in Surrey and the M40 in Buckinghamshire had the worst traffic in Europe with more than 220 thousands vehicles using it every single day.
In a highly controversial move it says key roads in Berkshire, Buckinghamshire, Surrey and Hampshire should be improved to cope with the growing problem.
This report is from our Transport Correspondent Mike Pearse.
The M40 southbound near Bicester is now fully open after a crash involving two lorries in the early hours of Saturday morning.
An overturned lorry carrying a load of frozen offal has blocked the M40 Southbound just before junction 6 at Watlington in Oxfordshire.
Thames Valley Roads Policing Unit has said that recovery work is continuing on M40 between junction 6 and 7. Expect severe delays.
A man has died after the van he was driving was involved in a collision on the M40. The accident happened shortly before 7pm. The crash involved a HGV and a van in lane one of the southbound carriageway between junctions 6 at Watlington and 5 at Stokenchurch.
Junctions 6 to 5 southbound are closed and are expected to remain closed for approximately three hours. There is significant congestion on the M40 and motorists are advised to avoid the area.
Signposted diversion routes via the A40 are currently in place.
Officers from Thames Valley Police are appealing for witnesses. Anyone with information is asked to contact PC Perry Knight from Roads Policing based at Bicester, via the 24-hour Thames Valley Police enquiry centre on 101 quoting URN 1300 18/6.
The family of a new mother who was killed in an accident on the M40, have paid tribute to her. Joanna Bull, nee Pedley, aged 29, died on Friday. Her 5-week-old daughter, who was travelling with her, was airlifted to hospital.
In a statement released through the police, Joanna Bull's family said:
“Jo, who was tragically killed in a car accident, was a loving wife, mum, daughter, sister, grand daughter, niece and friend to so many and loved by all who knew her.
“She died on her way to visit her mum Teresa, with her five week old daughter Ruby, to meet newborn cousin Harry (11/06/2014) for the first time, and to have a catch up with big sister Soph, and niece Nelly aged two.
“Jo was vibrant, beautiful, and caring in so many ways. A girl who added zest to a room and who had found true love and happiness with her husband of just one year, Dave.
“To have her taken from her family at such a happy time is utterly unbearable.
“Jo, we never had the chance to say a proper goodbye, but we will never forget how much fun and laughter you brought into all our lives, you will remain in our hearts and memories always.”
Traffic is queueing and two lanes are closed on the M40 London bound in Buckinghamshire between junction 4 A404/A4010 (High Wycombe Handy Cross Roundabout) and junction 3 A40/A4094 (Loudwater). A lorry has overturned and recovery work is ongoing.