Hugh Borbidge, BSME, Director of Engineering Animations
We, as vehicle operators, avoid collisions every day. We stop for red lights, brake when a car cuts us off, and slow down if there are children playing close to the roadway. In these avoidance situations, there are three components: Perception, reaction and braking.
Perception is when we first notice a hazard or the need to react to something. Reaction is the time taken to respond to what was perceived. A typical daytime perception/reaction time for a vehicle operator is about 1.5 seconds, meaning that, when you notice a hazard you keep traveling at the same speed for 1.5 seconds before you start applying the brakes. Braking is the minimum time it takes to bring the vehicle to a stop. Every bit of time in this series of events equates to a certain distance traveled. For example: Continue reading “Perception – Reaction – Braking”
The simple method is the easiest and fastest method as the name implies. The vehicle is treated as one object. The chassis and wheels do not move independent of each other. They all move as a unit. In the image above, the red lines represent the tire paths. You can see that the front and rear tires follow the same path even as the vehicle makes a turn. This is not scientifically accurate but can sometimes be useful for a “down and dirty” review for things like basic spatial relationships. 
