A driver has been arrested on suspicion of drink driving after a crash that closed both lanes of the A30 at Penzance this afternoon.
The grey Vauxhall Astra left the road near Tesco at Eastern Green, had gone into some railings and collided with an electrical control box for traffic lights, ending up on its side in the central reservation at around 3.45pm.
A spokesman for Devon and Cornwall Police said the driver was treated on the scene by paramedics for minor injuries.
He said: "The driver was arrested on suspicion of drink driving and taken by police to custody for further testing."
Traffic is being diverted along Jelbert Way while Western Power check the control box to isolate it and make sure it was safe.
Five firefighters from Penzance were called to the scene.
A spokeswoman for the fire service said that when the crews arrived the box was "smoking and still live".