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Analysis of real-world crash data from the USA shows that 11.5 per cent of pedestrians struck by large sport utility vehicles (SUVs) are killed, compared with 4.5 per cent of pedestrians struck by passenger cars. The design of the vehicle front-end structure has a substantial influence on injury outcome when pedestrians are struck by vehicles. In the context of the rising population of SUVs, it is important to determine the causes of their increased hazard to pedestrians. In this paper, validated multi-body models are used to show that the shape of SUVs results in higher pedestrian injuries to the mid-body regions compared to passenger cars. Analysis shows that the mass difference between cars and SUVs is not significant for pedestrian injury causation and it is shown that an important effect of the higher front profile of SUVs is that the pedestrian is struck more centrally with respect to the body's centre of gravity, increasing the momentum transfer in the primary impact. A further important effect of the higher bonnet leading edge is that there is a direct impact to the mid-body region, which explains the significant abdomen and other internal injuries reported from real-world SUV/pedestrian impacts. By comparison, head injuries sustained from primary vehicle contact are shown to be similar or slightly lower for SUV/pedestrian impacts compared to car/ pedestrian impacts. However, real-world evidence and the current models suggest that the secondary impact with the ground is more severe in SUV/pedestrian impacts compared to car/ pedestrian impacts. Overall, these results show that the empirical finding that SUVs are more hazardous for pedestrians than passenger cars is primarily a function of the high bumper and bonnet for such vehicles.

The most important factor in pedestrian injuries from vehicle collisions is the impact velocity. In cases where the impact configuration can be ascertained, the most common method now used to determine vehicle speed involves the pedestrian projection distance. The more traditional method of using tyre brake marks is losing applicability as ABS braking systems become more common. The two most common impact configurations are wrap projection and forward projection, these being determined by the vehicle/pedestrian geometry and the initial conditions of the impact. In this paper, two models are presented for pedestrian forward and wrap projection impacts. These models are predicated on separating the total projection distance into the individual projection distances occurring during three principal phases of the collision. The models are novel as they use a rigid single-segment body representation of the pedestrian, include explicit modelling of the impact phase, and also allow for uncertainty in the input parameters. Published data are used to provide distributions for the input variables such as pedestrian and vehicle masses, etc. The model predictions of impact speed from overall projection distance are validated by comparison with real-world accident data.

This paper proposes from fundamental mechanics that the specific energy ( E/ M) absorption characteristics of motorcycles and scooters in frontal impacts are similar where the primary load path is through the front wheel and fork assembly. Examination of 43 barrier test results for 14 different model types of motorcycle and scooter over the impact speed range from 10km/h to 76km/h shows that the specific energy versus wheelbase shortening characteristics are similar and that a single specific collision energy ( E/ M) regression equation with its associated statistical distribution ( r2=0.845) can be used to represent the motorcycle and scooter populations in frontal impact for wheelbase shortening up to 0.45m where the front-fork and front-wheel assemblies remain intact, albeit deformed. Data from 31 staged tests where motorcycles or scooters impacted stationary cars at 90° are used to obtain the energy absorption characteristics of the sides of cars subject to frontal motorcycle or scooter impact. These two regressions are used to estimate collision energy Eca from the permanent deformation or penetration depth of the collision partners, which, when substituted into the standard impact energy loss equation with the appropriate collision partner masses, yields an estimation of collision speed Vccs. This procedure for calculating collision closing speed Vccs is validated against 13 staged tests (six 90° impacts against stationary cars and seven angled impacts at angles up to 45° from the normal, four of which were against moving cars) and shows that the predicted Vccs speeds bound the actual speeds with a standard deviation of 11.2km/h for collision closing speeds up to 122km/h.

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