ICR-14-46 Proceeding of International Crashworthiness Conference 2014 1 | ICRASH2014 Opportunities for heavy truck front end compatibility with passenger vehicles K Friedman*, D. Mihora**, J. Hutchinson** *Friedman Research Corporation, 1508-B Ferguson Lane, Austin, TX 78754 **Friedman Research Corporation, 81 David Love Place, Goleta, CA 93117 Abstract - By 2030, substantial increases in the number heavy trucks are expected to be on roadways throughout the United States. Currently, three to five thousand occupant fatalities occur in the vehicles impacted by heavy trucks. A significant portion of these engage with the front end of the heavy truck. The use of radar systems has been shown to significantly mitigate many of these rear end crashes. In this study, the use of deployable front end airbags is evaluated in terms of the potential effects on the struck vehicle in front and rear end impacts with passenger vehicles. A virtual testing methodology for evaluation of various designs under impact conditions is described. The study reports on the potential effects of radar activated heavy truck front end airbag systems on crash mitigation in front and rear end impacts. Keywords: Heavy Trucks, Compatibility, External Vehicle Airbags, Radar Activated Airbags, Front Underride, Rear Underride INTRODUCTION Due to the size and mass of heavy vehicles, the problem of compatibility with other road users is a serious issue. Trucks in the United States are stiff, heavy and high off the ground and pose a serious threat to occupants of other vehicles in the event of an impact. In passenger vehicle to truck impacts the front of the truck is the most frequently involved damage area. By 2030, substantial increases in the number of long-haul, medium and heavy trucks are expected to be on roadways throughout the United States. In this study, the use of deployable front end airbags is evaluated in terms of the potential effects on the struck vehicle in front and rear end impacts with passenger vehicles in conjunction with the radar activated deployment. A virtual testing methodology for evaluation of various designs under impact conditions is described. Characteristics of the airbag system are described. Discussion of finite element models used and their validation are included, as well as examples of results associated with a range impact severities. The study reports on the potential effects of radar activated heavy truck front end airbag systems on crash mitigation in front and rear end impacts including the reduction in struck vehicle crush and struck vehicle acceleration across a range of impact conditions. BACKGROUND The need for compatibility of heavy trucks with the passenger vehicle fleet has been known since 1953 when a rear underride guard requirement (393.86) was created by the Interstate Commerce Commission 1 . By 1971 Deleys and Ryder [2] reported that the need for underride guards on trucks and tractor-trailers was generally recognized among experts and the industry. Their work was conducted to assure inter- vehicular compatibility and crash energy control. They showed that a maximum height of 450 mm (18”) would address the range of vehicles using down to fifteen inch wheels. They reported force measuring force levels of 168,000 lbs in rigid designs and 90,000 lbs for yield designs with 24” stroke. They observed that with guards that deformed, constant force stroke was superior to increasing ramp force or decreasing ramp force characteristics, when evaluating the striking vehicle crush and decelerations. Their work showed that the requirements of 393.86 were inadequate. In 1972, the Transportation Safety Board, reported that designs to prevent the fatal underride of passenger vehicles with trucks was needed and apparent.[3] In 1974, Martens, [4] observed that in addition to underride design implementations, design consideration was needed to ensure vehicle suspensions during heavy braking did not allow the vehicles to be susceptible to underride or override.