Minoo Shah

Driver Injuries in US Single-Event Rollovers

This paper will investigate occupant injuries which may be sustained during a single-event crash with known roll mechanism. The data was obtained from the weighted National Automotive Sampling System/Crashworthiness Data System (NASS-CDS) for calendar years 1992 to 1996. The effect of number of rollover turns, roll direction, ejection and belt usage on driver injury responses was analyzed in single-event trip-overs. Trip-overs were chosen for the analysis because they account for over 50% of rollover crashes. The number of rollovers was divided in 3 categories: 1/4 to 1/2 turn, 3/4 to 1 turn and above 1 turn. Roll direction was either roll-left or a roll- right along the longitudinal axis of the vehicle. Roll-left represents a roll with the driver side leading, while a roll right is with the right front passenger side leading. In the database used in this study, there were three times more belted drivers than unbelted. Ejection was more frequent when the driver was unbelted than belted. Of the 50,504 unbelted drivers, 27% were completely/partially ejected, while, of the 150,426 belted drivers, less than 1% were ejected. The rate to be seriously injured was higher when the driver was completely or partially ejected. Drivers in a roll-left trip-over were most commonly ejected through the left front area (for example, left door) of the vehicle, while drivers in a roll-right were ejected from the left front area and the roof. Of the non-ejected drivers, the rate to be seriously injured seemed higher for unbelted drivers than belted, at 2.2% and 1.1% respectively. For belted drivers in a roll-left, injuries were most frequent in the head, lower extremity (LX), thorax and upper extremities (UX), while, in a roll-right, injuries were most often to the spine, head, and thorax. Spinal injuries resulted when the vehicles rolled right, independent of the number of rolls. Unbelted drivers who rolled left, sustained serious injuries to the head, LX, thorax and UX, while those who rolled-right had serious injuries to the spine, head and thorax. Field data can be useful in the development of safety-countermeasures for rollovers as it provides insights on the significance of various parameters. The results of this study suggest the need to first prevent ejection by keeping the occupant in the vehicle. This could be accomplished by changing driver behavior through increased seat belt use and through technology by helping to obstruct ejection paths. Occupant/vehicle contacts should also be reduced to minimize the potential for injuries. In addition, a better understanding of the head, thorax, spine and lower extremity injury mechanisms is essential for the development of future safety-countermeasures.

US and UK Belted Driver Injuries with and without Airbag Deployments - A Field Data Analysis

This study compares the effect of U.S. and European airbag deployments on injury outcomes for belted drivers in frontal crashes. Two accident databases were used: the weighted and unweighted National Accident Sampling System (NASS-CDS) from the United States, calendar years 1995-1996; and the unweighted Cooperative Crash Injury Study (CCIS) from the United Kingdom, calendar years 1992-1998. The parameters investigated were Injury Severity Score (ISS), Equivalent Test Speed (ETS), occupant weight, occupant height, and seat location. For UK deployed cases, all severely injured drivers were involved in a crash with ETS>24 mph (39 kph), while approximately 70% of the severely injured U.S. drivers were in crashes with ETS>18 mph (29 kph). In the United States, 6 out of 47 deployed cases involving a severely injured (ISS>12) driver occurred in an accident with ETS 12 in the seat forward location when the airbag did not deploy.

The Effectiveness of Adjustable Pedals Usage

The objective of the study presented in this poster was to determine the driver-airbag module distance with and without adjustable pedals. For this study, 20 volunteers were tested in a small and large vehicle equipped with adjustable pedals. The pedals could be adjusted through extension towards the driver. The volunteers were divided into 3 height groups: short (5th percentile), medium (50th percentile), and tall (95th percentile). The volunteers sat in each vehicle and adjusted the pedals in 3 different positions: (1) Normal position, which corresponds to actual production pedal location; (2) Comfortable position, which corresponds to the driver desired pedal extension; and (3) maximum tolerabIe position, which corresponds to maximum drivable pedal extension. This position was used to obtain subjective feedback from the volunteers. For each position, the volunteer drove along a prescribed road course. The subjects comfort was evaluated through a questionnaire. The results showed the effectiveness of adjustable pedals, in particular for short-statured drivers particularly in the large vehicle. For short-statured drivers in the comfortable position, the pedal extension was higher in the large car than in the small car. However, the increase in chest-to-steering wheel distance was similar in both vehicles. This suggests that a short statured can comfortably increase his/her chest distance by 40 mm with pedal extension. For the covering abstract of the conference see ITRD E203643.