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This paper presents findings based on the examination of time-series tire pressure data. Tire pressure is important to vehicle safety due to its effects on vehicle handling and stability, as well as the impact that inappropriate tire pressure has on tire wear and tire failures. Previous research such as NHTSA’s 2001 Tire Pressure Special Study sampled vehicle populations and recorded tire pressures at a single point in time. Such studies yield important insights into tire pressures on individual vehicles and across the vehicle populations, but cannot provide insights into the behavior of tire pressures over time. The data presented in this paper was measured using the tire pressure monitoring system (TPMS) data from Tesla Model S vehicles. Using Tesla’s on-board diagnostic data logging and remote data retrieval capabilities, the time history of each vehicle’s tire pressures was recorded and fleet-wide data was analyzed.

High-intensity discharge (HID) headlamps are increasingly being employed in place of incandescent headlamps for automotive forward light systems. While the post-impact analysis of incandescent bulbs and filaments to determine the power state at impact is a mature field, there is little information currently available in the literature that can be used to determine if an HID headlamp was powered at the time of impact. HID headlamps differ significantly both in architecture and operation compared to incandescent headlamps; the light is produced by passing electrical current through a gas and generating a luminous arc, rather than by resistive heating of an incandescent filament. Though the filament examination techniques often used by accident investigators cannot be directly applied to HID lamps, the unique features of these lamps provide opportunities for new methods. This paper presents the results of stationary impact tests performed on a representative HID lamp.