Most people think that they are good at doing many things at once, even though some may argue that this may be feasible for some more than for others, the reality is that even if this was true, physically we cannot focus our gaze on two things that are at different distances at once.
On the other hand, we have to consider the reaction times involved in changing from one action to another, this is explained by Mark Green PhD, who is one of the leading forensic consultants of experimental psychology focused on perception, attention, time and the human factor.
There are several components that are involved in a person's reaction time:
- Mental process: This is the time it takes for a driver to spot an obstacle in their path, and make the decision on what to do:
Example: Something draws attention in the peripheral vision of the driver, then he analyzes the object and realizes that it is a person in his way, then combines this with the notion of distance and speed to determine what is happening and what will happen if he does not react. He eventually makes a decision to brake thoroughly rather than turn.
- Movement: the time it takes to move your foot from the accelerator to the brake or to turn the steering wheel.
- Vehicle Reaction: The driver pressing the brake does not immediately stop the vehicle, there are many factors to consider such as physical forces, gravity and friction.
On average, a person will take to react between .7 seconds if they are waiting for the situation and 1.5 seconds if it is a surprise, and up to 2.5 seconds if they are distracted with their eyes on a cell phone.
To make a case, with standard data from the Society of Automotive Engineers in the US, an average vehicle traveling at a speed of 40 mph (Average speed in urban areas), which is crossed by a pedestrian 197 feet away the following will happen:
If you are waiting for it, it will brake 49 feet before running over the pedestrian
If you are not waiting for it, the vehicle will be able to stop at 19 feet from the individual
If it came as a surprise, you will stop less than 3 feet from him; but
If you are looking at your cellphone, the vehicle will run him over at 28 mph, it will travel 60 feet before you even realize that there is a person standing in front of you and you will begin to brake just 50 feet from him. You will finally stop your vehicle 56 feet after running the pedestrian over.
Sending a text message, on average, requires you to take your eyes off the road for 4.6 seconds, at a speed of 54 mph, the vehicle will travel the equivalent of a football field with your eyes closed.
16% of traffic accidents that resulted in death were due to distractions while driving (It is presumed that most of them were due to "texting" while driving).
20% of injuries reported to insurers in 2009 are due to the same reason.