Study of the Measurement of Generation 2 Toyota Event Data Recorders in Low-Speed Side Impacts 2021-01-0904

Automotive Event Data Recorders (EDRs) are often utilized to determine or validate the severity of vehicle collisions. Several studies have been conducted to determine the accuracy of the longitudinal change in velocity (ΔV) reported by vehicle EDRs. However, little has been published regarding the measurement of EDRs that are capable of reporting lateral ΔVs in low-speed collisions. In this study, two 2007 Toyota Camrys with 04EDR ECU Generation modules (GEN2) were each subjected to several vehicle-to-vehicle lateral impacts. The impact angles ranged from approximately 45 to 135 degrees and the stationary target vehicles were impacted at the frontal, central, and rear aspects of both the driver and passenger sides. The impact locations on the bullet vehicles were the front and rear bumpers and the impact speeds ranged from approximately 7.9 to 16.1 km/h. Instrumentation was mounted at the approximate center of gravity (CG) of the target vehicles, as well as on the front reinforcement bar, rear body panel, airbag ECU, B-pillars, and C-pillars to evaluate the varying lateral ΔV (ΔV_y) readings from the 3 sensor locations (ECU, B-pillar, C-pillar) represented in the Toyota EDR and to account for rotational (yaw) effects on the data. The lateral ΔVs reported by the Toyota EDRs were then compared to the recorded ΔV_ys from the reference instrumentation mounted within the test vehicles. A comparison of the data revealed a general under-reporting of impact severity from the Toyota EDRs at the ECU sensor when compared to reference instrumentation at the vehicle CG for impacts near the center of the target vehicle where the vehicle typically rotated about its frontal aspect. There was a general over-reporting of impact severity from the Toyota EDRs at the ECU sensor when compared to reference instrumentation at the vehicle CG for impacts near the front (heavy) axle of the target vehicle where the vehicle rotated about its rear aspect. Rotational data from the reference instrumentation and the distance between the ECU and reference instrumentation at the CG was also utilized to calculate the corresponding ΔV_y at the ECU location for a direct comparison to the Toyota EDR measurement at the ECU (maximum of 12.0% difference). A comparison of the data recorded at the Toyota ECU sensors and the reference instrumentation mounted to the ECUs revealed accurate measurements by the Toyota ECU sensor (maximum of 7.6% difference). Differences in reported values between the 3 aforementioned Toyota sensor locations, as well as non-recordings and longitudinal ΔV recordings from the Toyota EDRs were also evaluated.