Police were called at 9.48pm on Friday, 11 March, to a car in collision with a pedestrian and subsequently a house on the eastbound A406 in Neasden.
The pedestrian – a man aged in his 30s – was pronounced dead at the scene.
Enquiries are ongoing to trace his family, believed to be overseas.
A passenger in the car – a man aged in his 50s – was taken to hospital. His condition remains life-threatening.
The driver of the car – a man aged in his 40s – was arrested on suspicion of causing death by dangerous driving. He has also been taken to hospital, where his condition is not life-threatening.
The car is a white BMW. It collided with a house causing significant structural damage. Lane closures remain in place on the A406 as work continues to remove the car and ensure the building is safe.
Detectives from the Serious Collision Investigation Unit are investigating. Any witnesses or anyone with dashcam footage are asked to call them on 020 8246 9820, ref 7729/11mar.