Traumatic brain injury (TBI) is the leading cause of death and long-term
disability in road traffic accidents (RTAs). Researchers have examined the
effect of vehicle front shape and pedestrian body size on the risk of pedestrian
head injury. On the other hand, the relationship between vehicle front shape
parameters and pedestrian TBI risks involving a diverse population with varying
body sizes has yet to be investigated. Thus, the purpose of this study was to
comprehensively study the effect of vehicle front shape parameters and various
pedestrian bodies ranging from 95th percentile male (AM95) to 6 years old (YO)
child on the dynamic response of the head and the risk of TBIs during primary
(vehicle) impact. At three different collision speeds (30, 40, and 50 km/h), a
total of 36 car-to-pedestrian collisions (CPCs) were reconstructed using three
different vehicle types (Subcompact passenger sedan, mid-sedan, and sports
utility vehicle (SUV)) and four distinct THUMS pedestrian finite element (FE)
models (AM50, AM95, AF05, and 6YO). We assessed skull stress and brain strains
besides head linear and rotational kinematics. Our findings indicate that
vehicle shape parameters especially bonnet leading edge height (BLEH), when
being divided by the height of the Center of Gravity of the human body,
correlated positively to head kinematics. The data from this study using
realistic vehicle structures and detailed human body models showed that smaller
BLEH/CG ratios reduced head injury criteria (HIC) and brain injury criteria
(BrIC) values for the car center to mid-stance walking pedestrian impacts but
with low-to-moderate R squared values between 0.2 to 0.5. Smaller BLEH/CG
reduced head lateral bending velocities with R squared values of 0.57 to 0.63
for all impact velocities, and reduced HIC with R squared value of 0.62 for 50
km/h cases. In the future, simulations with realistic car structures and
detailed human body models will be further used to simulate impacts at different
locations and with various body shapes/postures.
