Abstract
Objective
On March 23, 2018 a Tesla Model X driver was killed in Mountain View, CA after colliding with a previously collapsed crash attenuator at a speed of 31.7 m/s (70.8 mph). The attenuator, which must be repaired following a collision, had been struck 11 days prior by a 2010 Toyota Prius at a minimum speed of 33.9 m/s (75.8 mph). The Toyota driver survived. The maintenance of traffic safety hardware and benefit of the crash attenuator are evaluated.
Methods
Public information from an NTSB investigation is used to evaluate crash impact severity. Vehicle crash data from Event Data Recorders (EDRs) are compared with test data for the SCI Smart Cushion 100GM crash attenuator. An idealized triangular crash pulse is used to estimate longitudinal peak impact acceleration, and longitudinal impact energy is calculated. The medical outcomes for drivers are considered.
Results
The California Department of Transportation (Caltrans) maintenance and repair program for safety critical traffic safety hardware was found to be ineffective. The Tesla collision into the nonfunctional attenuator was estimated have roughly three times the impact force to the passenger compartment as it would have been if striking a functional attenuator.
Conclusions
The Tesla driver could have survived the collision had the crash attenuator been functional. Roadway management and timely maintenance of safety critical traffic hardware are necessary to ensure safety.