Thatcham, which will represent the Association of British Insurers and Lloyd's Motor Underwriters Association (LMUA), is a specialist in head restraint and security ratings.
Representatives from Thatcham have become members of the board of directors at Euro NCAP, Europe's leading proponent of vehicle safety.
Both organisations say the union will enable an exchange of vital data on leading edge automotive development, tackling numerous aspects of vehicle safety.
Thatcham chief executive Peter Roberts said: 'This new alliance will result in direct benefits for drivers, their passengers and pedestrians - it is a major milestone for the motoring public.'
He added that Thatcham's pioneering work in the field of head restraints, whiplash injuries and security ratings will be of particular value to the enlarged Euro NCAP organisation.
'Euro NCAP is recognised by the EC and consumer groups in every European country,' he said. 'We will draw upon their vast experience and contribute our expertise in return.'
A spokesman for Euro NCAP said: 'Thatcham's arrival will further strengthen Euro NCAP and our ability to help save lives.'