Schlumberger Artificial Lift crew was heading to Rig-82 after receiving a call out at 5 am. Driving started at 5:38 am and on the way missed the correct turn to the rig. The driver encountered an incline followed by left turn and responded by applying break and turning steering to the left side. The vehicle came to a complete stop on the edge (both right tires were off the edge of the embankment). As the driver was trying to manoeuvre the vehicle off the edge, he turned the wheels to the right and the vehicle lost balance and toppled off the side, landing upside down Why it happened/Finding : Absence of road signal indicating immediate sharp left turn after inclined road.  The Driver didn't anticipate the sharp curve after the inclined road. No traffic barrier installed at the sharp turning session of an elevated road.  Vehicles RAS inspection was not valid. Vehicle's tire was in bad condition.