When driving, the focus should always be on getting safely from one point to another. Most drivers do just that – most of the time anyway – without giving it a second thought. The problem is, even the best drivers sometimes slip up, get distracted, and become part of the grim statistics.
Each year on average 42,000 people die and another 2.2 million are seriously injured or crippled in roadway crashes. Another fact: vehicular crashes are the No. 1 cause of death in the United States for 3- to 34-year-olds.
We all know about the hazards out there, including: bad weather, potholes, construction zones, fog, glare and other bad light conditions, just to name a few. Since we’re in northern Michigan, throw in a few deer and turkeys, and winter (snow drifts, white-outs and black ice). Add to the mix the other drivers, bikers and pedestrians who often act suddenly, unpredictably and sometimes as if they have a death wish.
There are also the hazards that ride right along with you in the car. I’m talking about cell phone calls, text and tweet messages, the radio, kids (or even adults) fighting in the back seat, pets jumping around unrestrained, iPod adjustments, interesting roadside scenery, that french fry that just fell between the seats, etc. (I think you get the picture). Distractions in the car make it hard to focus on the task of driving. Fact: distractions are right up there with drunk driving and speeding as a leading cause of accidents.
One last hazard may be looking at you in the mirror. People generally think that accidents are caused by factors outside their control – but they’re wrong. According to the Federal Highway Administration (FHWA), and based on decades of accident research, the actions (or inactions) of individual drivers themselves are the sole cause in more than half of all vehicle crashes. In other words, most crashes are caused by driver error. The FHWA also reports that driver actions are a contributing factor in almost every vehicular collision.
So what can you do about it? The answer: plenty.
The right response
One good way to become a better, safer driver is to understand and improve your response time.
Response time (also known as “reaction time”) is the time it takes to fully respond to a stimulus such as a road hazard, a traffic sign or signal, brake lights, another car entering the roadway, a fallen tree, a biker, walker or runner, deer suddenly running into the road, or any other external factor you can think of. The response is what a driver does as a result of the stimulus, such as: slamming on the brakes, speeding up, swerving, changing lanes, blowing on the horn, etc.
A lot of things have to happen before the driver can respond appropriately. In fact, total response time has four unique stages that always occur in sequence. These stages are: detection, identification, decision and response.
Detection time is the time it takes the driver to become consciously aware of a hazard after it comes into the visual field. To drive is to be continually exposed to hazards. Being continuously aware of the surroundings – that is, paying attention to driving above all else – is the only way to reduce the time associated with detection. Detection time is impaired by distractions and many people are no longer with us for one simple reason – they failed to detect a hazard before it was too late. One common distraction: talking or texting on the phone while trying to drive.
The time it takes for the mind to figure out the nature of the detected hazard is known as “identification time”. This may seem like a minor point, but hazard identification time is a very important factor. For example, imagine two white lights approaching on a rainy night as you drive down a dark two-lane rural road. At first glance the lights appear to be an oncoming vehicle – no problem. However, as the lights get closer, it turns out they are on the back of a slow-moving farm tractor – now that’s a problem! In cases like this, the time lost in correctly identifying a hazard can mean the difference between life or death.
After a hazard has been detected and correctly identified comes the time when one has to decide what to do about it – this is called “decision time”. The best drivers are decisive and able to quickly act to avoid a hazard.
The final stage of total response time is the time it takes for the body to actually perform whatever action that the driver has decided upon, for example hitting the brakes. This varies between people – some are quicker than others.
Hey! All this time has gone by and we still haven’t acted! This is why response time is so important. No matter how good a car handles, how good the brakes are, or how many stars it has in crash tests, if response time is too slow, there’s going to be an accident!
To put it all together, just imagine you’re cruising along at 55 mph. You crest a hill and suddenly encounter an object in the middle of the road (pick any object you want to imagine). Your response time starts when you detect the presence of the object. Next, your brain identifies the fact that the object is only a couple hundred feet away. Finally, your mind processes the fact that you only have 3 seconds till impact and you decide to swerve and/or slam on the brakes! Only then can your brain instruct your hands to respond by turning the steering wheel or your foot to move off the accelerator and push on the brake pedal.
Please note: don’t confuse response time with the time it takes to turn the wheel or brake – In fact, the swerving or braking in our example only occurs after the end of response time. The time and distance it takes to turn or stop a vehicle is governed by the laws of physics (initial speed, vehicle weight, steering or braking force applied, roadway friction, etc.) So, the total time it takes to complete the maneuver is the sum of the response time (controlled by the driver) and the time it actually takes to physically turn or brake (controlled by the laws of physics). Hopefully, in our example, all this occurs before a collision with our unnamed imaginary object occurs.
Fractions of seconds make the difference
OK, so you’re in a hurry. You’re distracted. You ran out of cat litter, or you’re running late for work or a hair appointment. Chances are, the last thing on your mind is getting from point A to point B safely. This is precisely when you’re most at risk. At one point on the way there or back, there could be (and someday there will be) a situation where time isn’t measured in minutes or hours – it’s measured in fractions of seconds. Whether you survive these critical moments will depend entirely on your alertness and your ability to react quickly and correctly to the random hazards you encounter on the road.
Internalizing the concept and importance of response time will help any driver avoid an accident. Enlightened drivers are vigilant to changing conditions and hazards – they know that the unexpected can and will happen at any time. They know their own limits and control of their available response time by adjusting their speed and driving style to changing conditions. They avoid tailgating and other aggressive driving habits and always allow for adequate stopping distance. Finally, a good driver never assumes the other drivers on the road will behave properly – chances are they won’t.
When properly focused on the task of driving, a driver can not only increase available response time, but can also dramatically reduce total response time by detecting and identifying hazards quicker, being decisive and practicing sudden stops and avoidance maneuvers so they become second nature. When driving distracted, response time dramatically increases and you become a hazard to yourself and those around you.
I hope you think about this next time you buckle up.
This blog is dedicated to Kile, my youngest son, who is just starting driver’s training and will soon join the motoring public at large – Watch out! If you have any questions or comments about this or any other general engineering related topic, please feel free to contact me at firstname.lastname@example.org.