Habit interference is one of the most important issues in accidents and there are many ways of considering this.

Psychology Research and Mental Habits
Psychology research has shown that mental habits are formed when people repeat certain actions frequently. Mental habits do have their positive side in that they help save people both time and effort. Almost every driver will relate to the experience of having reached a destination without being able to “remember” exactly how they got there.

Human conscious thinking cannot cope with more than a few pieces of information in a limited span of time and this enforces these “economical tendencies”. Intuitively, people try to use the limited resource of conscious thinking as economically as possible and this directly causes a lot of error tendencies.

Two Main Branches of Habit Theory

• Schema Theory - the basis of which is that people develop “scripts” in their minds, or automatic ways of thinking

• Habits - Habits are like a river, the more it flows, the deeper it digs a channel and the harder it is to change. Habit can be useful but occasionally, it catches people out.

Drivers need to process huge amounts of information all at the same time and they often do this without even thinking about it. Many mistakes, caused by habits, go by without causing too much hassle: someone might for instance forget to make a detour to go to a shop when travelling down a familiar route.

How Mental Habit Can Cause Driving Accidents
Turning down a certain road because the route is familiar is the type of mistake that is easily remedied. Other times, however, such errors can be quite serious. A bus driver took the top of his double-decker bus clean off through driving under a low bridge. Why? Because usually on that (familiar) route he drove a single-decker. This absent-mindedness, through habit, caused a very serious accident.

Even a habit of checking your phone right away when it beeps can be risky, too. The habit of reaching for the phone and checking it while driving causes accidents too. In fact, in a survey conducted by Ratedradardetector, they found out that the use of cellphone while driving is the number one reason for distracted driving, which then can cause driving accidents.

Novices and Experts and Accidents
It can be understood why novices make mistakes in complex situations but it's not so easy to understand why experts make mistakes as in the above example; the reason having been given, does help us realise the cause of the error.

In 1961, psychologists Fits and Jones noticed the role of habit interference in aircraft crashes. In 1983, another psychologist, Hendrick found that experienced airline pilots were two to four times as likely to make errors in reversed gear stick conditions as were inexperienced pilots.

In the USA, racing drivers on the road have higher crash rates than ordinary drivers. Employees of the New York Police Department, despite being highly trained drivers, have a crash rate that is nine times higher than the ordinary driver. It would appear then, that high performance is not higher safety. Experts are just as vulnerable to these attentional slips.

Perception in Road Traffic Accidents
Scientific studies of driving are uncovering more and more about human limitations. Humans have a wide range of vision but only a small part is accurate. Dr. Alison Smiley, a Traffic Safety Ergonomist, analysed films of eye movement in drivers and she found that people’s eyes tend to fixate for a brief period of time, then fixate on something else.

In 1988, Luoma studied driver's eye fixations and perceptions, using fixed objects such as road signs as targets. He found that when traffic signs were fixated they were always perceived. However, although 54% of eyes focused on the pedestrian crossing, they did not perceive. Only 8% of the study group both focused on and perceived the pedestrian crossing.

Also, houses which were 50 metres from the road were neither focused on nor perceived.

Hazard Perception
So the fact that people actually “look” at an object does not, therefore, always mean that they perceive it. They have not registered it in their mind.

Each fixation, when driving, takes about a third of a second and it is possible that where a person looks at crucial moments in time while driving could mean the difference between an accident or not.