A black VW Golf was found stopped at traffic lights on the A61 South Accommodation Road at Hunslet with the driver unconscious at the wheel. There were no apparent signs of a collision.
Police were contacted by the ambulance service just after 11.30pm yesterday (January 5)
The 59-year-old man was taken to hospital for treatment but was pronounced dead a short time later.
Police are appealing for any witnesses who saw the Golf, registration YL02UKC, travelling from Leeds city centre towards the M621 in the time leading up to the incident or who saw the vehicle stationary at the traffic light signals on South Accommodation Road near to Cross Green Lane.
Anyone with information is asked to contact Safer Roads and Neighbourhood Support via 101 quoting log number 1715 of January 5.