Cyclists in west London are being educated about the danger they face with lorries on roads.
The event organised by the Metropolitan Police is being held in Richmond Park on Saturday.
It aims to make cyclists aware that if they are on the nearside of a lorry when it changes direction, they may not be visible to lorry drivers.
Seven cyclists were killed in 2007 after being involved in collisions of this kind with a goods vehicle.
A spokesperson said this represents 50% of all collisions in which cyclists were killed in London last year.
Two lorries stationed in the park will be used for a practical demonstration for cyclists to participate in.
Officers will also be on hand to answer questions and to talk to cyclists about road safety in the Roehampton Gate car park.
Police sergeant Peter Lawson of the Metropolitan Police's Traffic Unit, said:
"More and more Londoners are starting to cycle and it is incredibly important that everyone who uses London's roads does so safely."
The event is supported by Transport for London.