When the traffic jam ends and the car reaches 30mph, the auto-pilot -- called "Traffic Jam Assist" -- hands control of the vehicle back to the refreshed driver.
The revolutionary technology, developed by engineers at US auto major Ford, is expected to be available on several of its models within five years. Prototypes are being tested at Ford's European research and advanced engineering centre in Germany and in the US, the Daily Mail reported.
Experts said its widespread adoption could help speed up traffic caught in jams by up to 37 per cent and reduce journey times by 20 per cent by helping cars keep pace more efficiently with the flow of the traffic.
The technology works using a camera and radar behind the rear-view mirror which scans the road ahead by picking out the white lines marking the lane, plus any other traffic.
Signals are then sent to the "brains" of the system in a computer central processing unit or "black box". Once a jam is detected, the car uses a voice command to ask the driver if they want to switch to Traffic Jam Assist.
If the answer is yes, then the car assumes command -- braking to stop a collision with the car in front or to slow down to meet its speed, and then accelerating to keep up with the flow of cars in front when they move off.
It will even recognise a car that "cuts in" ahead of the vehicle in front and take appropriate braking action needed.
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The system is designed only for motorways, but coping with the problems of urban traffic is just a matter of time, Ford bosses said.
Pim van der Jagt, MD of Ford's Aachen operation, said: "The car will stay in the middle of the lane even when the motorway takes a curve. It will accelerate, brake and steer itself in a jam." However, he insisted that the driver still has to pay some attention.
Ford research engineer Joseph Urhahne added: "Traffic Jam Assist could help make travelling through congestion a more relaxing experience and, by keeping pace with the flow of traffic, potentially help relieve road congestion."