Good driving depends on timing

Most people guess low when it comes to passing on a highway, making a turn in city traffic or braking

Motorists face innumerable decisions on the road: How much space do I need to pass? How long would it take to make a turn? In today’s column, Steve Wallace suggests that many of us can’t estimate the right time and space.
Photograph By DARREN STONE, TIMES COLONIST

Now that vehicular traffic has returned to a more consistent volume and reliable cyclical nature, it is worth reviewing some driving techniques which will help us return to predictable travel behaviour.
Most every action behind the wheel is going to take longer than anticipated by the average driver. This tendency is even more dramatic among those learning to drive. No matter which driving actions are referenced by a driving instructor, the student driver will most always predict these actions could be completed in less time and space than is the norm. When we are in the act of doing, time seems to pass more quickly than if we are simply waiting and inactive.

When students are asked to estimate how far it will take in time and space to pass another vehicle on the highway, they invariably guess low. To do a safe pass on a two-lane opposite direction road, at a reasonable highway speed, the average driver would need about eight to 10 hydro pole placements to complete such a manoeuvre. The average student driver will in the initial lesson schedule guess a paltry three to four poles. The danger in this underestimation is obvious.

The same characteristic presents itself when new drivers estimate the time needed to make a simple and unobstructed right or left turn from a complete stop at an intersection. It takes about six seconds for a right turn and a couple of seconds more to do a left turn, when the count begins with the first turn of the wheel to the complete centre retraction. Student drivers consistently guess low when asked to estimate this common driving action. The act of doing seems to skew their time and space estimate.

Many experienced drivers fall victim to a velocity principle. After travelling for an extended time at high speed, they are unable to estimate their speed reduction as they leave the freeway or highway. If asked to call out their speed with the speedometer hidden from view, they nearly always guess low, and are going much faster. After doing this drill with several thousand learners, only a handful have ever ended up 10 per cent over/under the 30 kilometre-per-hour target and posted exit speed. Try this at your earliest convenience on an extended trip with a co-pilot. Even experienced drivers have trouble reaching the 30 km/h over-under allowance. The tendency to take longer and further to do simple driving actions is very apparent when this drill is completed. Once again, more time and space will be needed for the above drill.

Most drivers underestimate the time and space necessary to make a quick and safe crash-avoidance stop. When new drivers are asked how much further it would take to stop a vehicle when the speed is doubled, they invariably answer twice as far. Physics students usually are the exception. They know from their studies that the relationship is a square proportion. It takes four times as far and nine times the skid, when the speed is tripled. It takes longer and further in time and space to stop than most drivers, not just learners, will estimate. That is why the most common crash is the rear-end collision.

It is much safer to avoid a crash by steering than braking. This not only reduces the potential to hit a vehicle ahead, but also negates the possibility of being rear-ended, as most following drivers do not appreciate the exponential nature of stopping distance.

We will never hit a space. We will never kill a space. Space cushion driving is the safest way to get around in the city or a rural area. Steering to a space to avoid a crash is preferable to braking. More on this is an upcoming column.

Steve Wallace is the owner of Joan Wallace Driving school on Vancouver Island. He is a former vice-president of the Driving Schools Association of the Americas, a registered B.C. teacher and a University of Manitoba graduate.