West Yorkshire Police are issuing a new appeal for information over the fatal collision at 4.30pm on December 6 between a Vauxhall Zafira and a Honda motorcycle travelling along the A6120 towards Horsforth, close to the junction with Fillingfir Drive.
The motorcycle left the road after the crash and its 17-year-old rider was pronounced dead at the scene.
Police Constable Carl Sapsford, of the Major Collision Enquiry Team, said: “This is a very busy road and the collision has occurred at the start of rush hour when there would have been a lot of motorists in the area.
“We have spoken to a number of people who have arrived on the scene shortly after the collision but are still keen to speak to anyone who witnessed the actual incident or saw either vehicle prior to the collision.”
Anyone with information should call West Yorkshire Police’s Major Collision Enquiry Team on 101.