Search Results

Crash data recorded by the restraint control module (RCM) installed in newer Ford passenger vehicles have recently become available to investigators. To quantify the accuracy of the crash data in low-speed collisions, two RCM-equipped vehicles were exposed to 84 aligned frontal barrier collisions with speed changes up to 13.5 km/h. The accuracy of the speed change reported by the RCM ranged from an underestimate of 1.8 km/h to an overestimate of 0.3 km/h. The error varied with speed change. The RCMs were mounted on a linear sled to investigate their sensitivity to specific collision pulse parameters. For both RCMs, the first eight acceleration data points were duplicated at the end of the data and the record of the crash pulse was often incomplete. Based on the results of this study, crash investigators need to carefully interpret the RCM-reported acceleration and speed change data before using it to reconstruct low-speed collisions involving Ford vehicles.

The Vetronix Crash Data Retrieval (CDR) system can download information recorded by the restraint control module (RCM) of newer Ford vehicles. In an earlier study, a 2003 Ford Crown Victoria and a 2003 Ford Windstar were exposed to 84 staged collisions with speed changes up to 13.5 km/h. After each test, crash data was downloaded from the RCM using version 2.1 of the Vetronix CDR software. In this study, the crash data was re-analyzed using the current version 2.4 of the software. Unlike version 2.1, version 2.4 did not report duplicate data points. Version 2.4 reported more accurate speed changes for the Windstar (average underestimate of 0.23 km/h) RCM but less accurate speed changes for the Crown Victoria (average underestimate of 0.73 km/h).

Most 1999 and newer General Motors (GM) vehicles have an event data recorder (EDR) that can record pre-crash speed incorporated into the airbag sensing and diagnostic module (SDM). The accuracy of the SDM-reported pre-crash speed over a wide range of speeds has not been previously tested and reported. In this study, the SDMs of three late-model GM passenger cars were artificially triggered while driving at a constant speed between 1 and 150 km/h. The SDM-reported pre-crash speeds were compared to speeds measured by a calibrated 5th-wheel of known accuracy. The results showed that the accuracy of the SDM-reported pre-crash speed varied with both speed and vehicle. The overall uncertainty associated with all three SDMs tested varied from a 1.5 km/h overestimation of vehicle speed at low speeds to a 3.7 km/h underestimation of vehicle speed at high speeds.

The purpose of this paper was to compare the damage to pickup truck bumpers produced by vehicle-to-barrier and vehicle-to-vehicle collisions of a similar severity, in order to determine whether vehicle-to-barrier tests can serve as surrogates for vehicle-to-vehicle tests in accident reconstruction. Impact tests were conducted on the front and rear bumpers of five pickup trucks. Each truck was subjected to an impact with a fixed barrier and with a passenger vehicle. All impacts resulted in pickup truck speed changes of about 8 km/h. Damage produced in the barrier and vehicle-to-vehicle collisions was similar if both collisions resulted in bumper mount damage on the pickup truck. If there was no bumper mount damage, then the bumper beam deformation depended on the shape of the impactor.

Collision data stored in the airbag sensing and diagnostic module (SDM) of 1996 and newer GM vehicles have become available to accident investigators through the Vetronix Crash Data Retrieval system. In this study, two experiments were performed to investigate the accuracy and sensitivity of the speed change reported by the SDM in low-speed crashes. First, two SDM-equipped vehicles were subjected to 260 staged frontal collisions with speed changes below 11 km/h. Second, the SDMs were removed from the vehicles and exposed to a wide variety of collision pulses on a linear motion sled. In all of the vehicle tests, the speed change reported by the SDM underestimated the actual speed change of the vehicle. Sled testing revealed that the shape, duration and peak acceleration of the collision pulse affected the accuracy of the SDM-reported speed change. Data from the sled tests were then used to evaluate how the SDM-reported speed change was calculated.