The 50-year-old man was on the Southend-bound carriageway when he lost control of his black Vauxhall Vectra at 6.50pm yesterday near the Fairglen interchange turn-off to Rawreth.
Paramedics tried to save him but he sadly died at the scene.
Essex Police said the events leading up to the crash were unclear but no other vehicle was involved.
Motorists were left queuing for two hours while the air ambulance landed, with some sitting on their car bonnets.
The A127 remained closed until 11.45pm while police carried out investigations.