The collision detection sensor placed on trucks usually measures the forces on the machine in “g” values. But what is worth knowing about this magical g-force value?
The unit of acceleration is m/s². The “g” notation for the acceleration due to gravity on Earth (9.81 m/s²) is also used as the illustrative unit of acceleration. The notation “g” was started to be used in the case of military aircrafts flying in small turns (first in 1922 by the famous American pilot, Jimmy Doolittle), and later for measurements in centrifuges used to train astronauts.
The term, which often appears in motorsport, is also used in the subsequent evaluation of accidents. Let’s recall a few memorable cases – some with more fortunate, some with sadder outcomes.
At the Silverstone race in 1977, British F1 pilot David Purley’s car decelerated from 173 km/h to zero in 66 centimeters, and his body was affected by a force of 178 g. The driver broke many bones and his internal organs were also damaged, but he survived and recovered. So far, it was the biggest impact anyone has survived.
Surely, many remember 1994, when three-time world champion driver Ayrton Senna from Brazil suffered a fatal accident, crashing into the concrete wall at the Imola race. He suffered such a severe head injury that he died after being taken to the hospital.
Luciano Burti, driver for Prost Racing, crashed into the rubber wall at the 2001 Belgian Grand Prix, experiencing a deceleration of approximately 80 g for a moment. Burti suffered a head injury, his doctors kept him in an artificial coma for days, and after several months of rehabilitation he returned as a test driver.
On June 10, 2007, at the Canadian Grand Prix in Montreal, Polish driver Robert Kubica was exposed to a force of 75 g for a millisecond when his car crashed into the wall at a speed of 230 kilometres per hour. The pilot got away from the accident without a scratch, he only sprained his ankle and suffered a mild concussion. Although the maximum force on the car was 75 g, the average deceleration was “only” 28 g.
On October 5, 2014, during lap 44 of the Japanese Grand Prix in Suzuka, French driver Jules Bianchi crashed into a construction machine at 130 kilometres per hour and slowed his car to a complete stop in about 5 meters. According to the 3D sensor placed in the driver’s headset, the head of the pilot, who suffered a serious brain injury, might have slowed down at 92 g. Although the driver miraculously survived the impact, he fell into a coma due to his serious brain injury and 9 months later.
Thanks to the development of safety systems, luckily, there are fewer and fewer fatal accidents in Formula 1. In the case of accidents, the forces effecting the driver’s head are usually not the same as the force on the chassis, and it is good to know that how long a given force effect lasts, it is a more important factor than the momentary deceleration. Under normal conditions, drivers typically do not experience more than 3-4 g of acceleration while racing.
Luckily, we cannot speak of F1-like traffic speeds with forklifts trucks, but when two machines collide, or when they collide with a wall or a column, serious forces can still occur. Truck fleet management systems are (also) designed to identify such cases (when, where, how much force impacted the machine? who drove it?). They also help to increase the individual responsibility of the operators through accountability and training. We can only expect a reduction in the number of dangerous situations and damage resulting from collisions if we manage to make progress in this regard. That’s what we have to work towards!
