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The sampling rate and synchronization of the pre-impact data stored by General Motors (GM) sensing and diagnostic modules (SDMs) have not been experimentally determined. The goals of this study were to measure the time shift between the SDM-reported data times and algorithm enable, sampling rate variation and the synchronization of the sensor data. In this study, two experiments were performed. First, the SDM of a 2002 Pontiac Sunfire was artificially triggered while the throttle position, engine speed, vehicle speed and brake signals were also being monitored at their source sensors. Second, the throttle and vehicle speed sensors were replaced with artificially generated inputs so the timing of the SDM recorded values could be compared to that of the known inputs. Sampling rate and data synchronization were determined by fitting the SDM recorded values to the measured sensor outputs.

Anti-lock brake systems (ABS) produce high levels of vehicle deceleration under emergency braking conditions by modulating tire slip. Currently there are limited data available to quantify the mean, variance, and distribution of vehicle deceleration levels for modern ABS-equipped vehicles. We conducted braking tests using twenty (20) late-model vehicles on contiguous dry asphalt and concrete road surfaces. All vehicles were equipped with a 5th wheel sampled at 200 Hz, from which vehicle speed and deceleration as a function of time were calculated. Eighteen (18) tests were conducted for each vehicle and all tests were conducted from a targeted initial speed of 65 km/h (40 mph). Overall, we found that late-model ABS-equipped vehicles can decelerate at average levels that vary from about 0.871g to 1.081g across both surfaces, and that deceleration levels were on average about 0.042g higher on asphalt than on concrete.