On behalf of NHTSA, the European Commission, and the Dutch Ministry of Traffic and Transport, the Safety department of TNO Automotive is performing numerical fleet studies using multi-body models. Aim is to develop strategies for optimisation and evaluating the effects in new vehicles based on proposed test procedures to minimise the total harm in car-to-car crashes on a fleet-wide basis. For these studies multi-body models are being constructed from existing finite element models. The front-end structure and passenger compartment are modelled in detail to provide realistic deformation modes. Furthermore dummies, airbags, belts and main interior parts like dashboard and steering wheel are included. Currently seven models are available, each of a different vehicle class. Two geometrical variants of the smallest vehicles are also included. The objective of this paper is to show the potential of the multi-body vehicle models for crashworthiness optimisation and/or evaluation of a fleet. To this end a fleet study on offset frontal impacts is performed in which sensitivities of relevant accident and design parameters are investigated by means of parameter sweeps over these parameters. The accident parameters include vehicle type, impact speed and overlap. The design parameters relate to the front-end geometry of the two smaller vehicles. A total set of over 3200 scenarios is simulated. Analysis of results is done on the basis of measures for the overall injury risk and based on separate injury values for different body regions. For the separate injury values clear trends are observed with respect to variations in design variables. For overall injury risk measures these trends are not so clear due to contradicting influences of the design variables on separate injuries. This complicates usage of the overall injury measures. © Woodhead Publishing Ltd.