This dashcam footage shows the moment a car violently flips over and rolls across three lanes of the M4 motorway following a high-speed road rage incident near Port Talbot last year.The footage shows two men driving at speeds of over 100mph, while repeatedly undertaking, tailgating and flashing their lights at each other along the eastbound carriageway in June 2018.The dangerous driving eventually causes one of the vehicles - a blue Mini - to veer across the road and smash into the barriers at the side of the carriageway.The impact then forces the car onto its roof and to violently roll back into the centre of the road, strewing glass, tyres and the contents of the vehicle across the lanes.South Wales Police have now confirmed that two motorists have been convicted of dangerous driving following the incident.Paul Carpenter, aged 44, from Boxhill in Surrey, and Wayne Sebury, 59, from Pontypridd, initially denied any wrongdoing but later pleaded guilty to dangerous driving.They appeared at Cardiff Crown Court on Thursday, April 11, where Carpenter was sentenced to six months in prison and disqualified from driving for 18 months.Sebury was given an 18 month community order, was disqualified from driving for 12 months and must also carry out 150 hours unpaid work.PC Kathryn Matthews, from the South Wales Police Roads Policing Unit, said: “This incident was a classic case of road rage where two motorists have driven dangerously, at high speeds, undertaking, tailgating and flashing their lights.“It is sheer luck that nobody was killed or seriously injured and the dash cam footage of the incident sends out a clear message about the consequences of driving in such an irresponsible manner.”South Wales Police added that witness evidence showed that Sebury drove his blue Mini and Carpenter his Ford Mondeo at speeds of up to 101mph shortly prior to the collision.