#StaySafeSaturday: Crash Avoidance and Electronic Stability Control

Avoiding a crash is ALWAYS preferable to attempting to “manage” the crash.  How a vehicle manages a crash is often referred to as “crashworthiness.” This concept will be addressed in later posts.  

The most significant crash avoidance technology relating to vehicle stability is electronic stability control (ESC). This technology reacts faster than the operator of a vehicle.  It does so by regulating braking, engine speed, and transmission adjustments. The concept of ESC has existed for decades, primarily in the aviation industry. When a passenger airplane encounters turbulence, avionics of the airplane stabilizes the airplane before a pilot can react. Historically without such a system, the pilot would attempt to correct the stability of the airplane. Many times the pilot would overreact, which would cause further instability to the airplane. This is commonly referred to as “pilot induced error.” The same occurs with drivers attempting to regain control of a vehicle that is starting to slide or rotate in an emergency steer maneuver. The driver is undertaking all reasonable actions as a driver perceives. However, the driver’s perception reaction can actually further the instability of the vehicle.

ESC identifies and reacts faster than a driver. Similar to the airplane turbulence scenario, the vehicle will stabilize itself to prevent a crash.   

ESC has existed in vehicles since the late 1990s. However, it was not until March 2007 that the National Highway Traffic Safety Administration (NHTSA) required vehicles weighing 10,000 pounds or less be equipped with an ESC system. NHTSA estimated that as many as 2,534 lives would be saved annually once all passenger vehicles had ESC systems. In 2004 NHTSA concluded that ESC was approximately 30% effective in preventing fatal single vehicle crashes for passenger cars and 63% for sport utility vehicles (SUVs).  

NHTSA allowed a “phase-in” for vehicle manufacturers to incorporate ESC from 2009 to 2011 model years. Beginning in 2012 all light vehicles were required to have ESC. Therefore, if searching for a used vehicle, only consider model years 2012 to the present as ESC is mandatory in selecting a safe vehicle.

Cyber Threats Leave Vehicles Vulnerable

Car TechnologyWe have become reliant upon Bluetooth, WIFI, USB devices, and intelligent traffic communications within our vehicles. These features can improve fuel economy, reduce driver fatigue, and increase traffic safety, but it is all at a cost. Increased technologies can allow for dangerous breaches of security in vehicles. The Federal Bureau of Investigations and NHTSA recently published an alert regarding this automotive cybersecurity. 

Vulnerabilities may exist within wireless communication functions of a vehicle allowing an attacker to gain access to vehicle systems. In August 2015, a vehicle was studied in an unaltered condition which allowed cyber-attacks to affect engine speed, brakes, steering, door locks, turn signals, radio, and GPS. Obviously, this is disturbing to consumers who have advanced electronics in their vehicles. The bulletin by the FBI and NHTSA while providing important information, did not address why this could occur or how it would be prevented.

Software safety is not only a software issue, it is a system issue. Software related hazards must be identified, understood, and mitigated considering that software interfaces with hardware, humans, and other software. Software safety is an integral aspect of the overall system safety plan and the methodology is documented in a system safety plan process.

Software safety is not the same as software reliability or quality assurance. A pragmatic way to determine software safety is by incorporating a bilateral safety process.

First, software functional coverage is a process focusing on functional design and hazard identification. Secondly, software development coverage focuses on specific development tasks to ensure high quality software is safe. The bilateral approach is a strategy intended to cover all aspects of software that can impact safety. The approach requires a system hazard analysis to identify hardware and software causal factors, identification of software at critical levels which will impact the level of rigor tasks performed by the software development effort.

With each model year, vehicles become more integrated regarding communications. It is necessary for designers and manufacturers of intelligent transportation systems to undertake system safety planning of software to identify and eliminate said hazards to the extent reasonably possible.