I have had forty years of experience as a Senior Civil Engineering Technician designing, constructing and maintaining roads. I have driven extensively in South Africa and in other countries and have observed driver behaviour as related to road conditions for many years.
Many South African drivers tend to blame the taxis for our high road death rate without realising that the taxi death rate runs at about ten percent year after year, while busses and other heavy vehicles account for approximately another ten percent, leaving a massive eighty percent at the door of the average motorist.
I found driving in the United States an absolute pleasure with everyone travelling at the posted speed and no weaving speed merchants. The drivers were as bad about indicating lane changes as South Africans but there was no closing of a gap when you changed lanes and everyone was considerate. Then we struck a Florida rainstorm that brought visibility down to about ten metres or less and I saw the bit of American insanity that causes hundred car pileups! Nobody slowed down! They all kept going at seventy miles an hour! Unfortunately there are some South African drivers who have the same habit!
I once spent three days and nights within hearing and sight of a major US freeway. In that time I heard one car passing at high speed and the police siren was about five seconds behind it!
How often don’t we hear the words: “I came over a blind rise and there it was! There was nothing I could do!” The simple answer is: “You were driving faster than was safe for the road conditions!”
Another common one is: “He stopped too suddenly in front of me and I hit him!” Absolute rubbish! No country has a statute that limits how suddenly a driver can stop. Internationally engineers agree that a two second interval is the minimum following interval in good conditions, with some recommending up to twelve seconds in snow! In the idle moments of a retired person I stand and watch the cars passing on a nearby highway and count the seconds as they pass a telephone pole. Approximately thirty percent are travelling not more than one second apart! It is simple enough. When the car in front of you passes a roadside object, start counting “One thousand, two thousand”. If you don’t finish the count you are following too closely!
If a car is following less than a second behind a big truck and the load falls off the truck it could land on the bonnet and come through the windscreen. At a two second following distance the load will hit the road first and the car’s airbags will probably save the occupants.
I have not driven in India, but the worst driving I have seen in terms of road rules was in Panama, but they drive slowly and there is no road rage. Result: fatal accidents are almost unknown and it is difficult to find a body repair shop!
Roads are not built by guesswork. A design speed is decided on. The international average time for a driver to recognise a danger and start braking is 0,6 of a second so the designer uses one second in his calculations. A side force of 0,6G is used for calculating the minimum radius of a curve and the “camber” (correctly “superelevation”) of the road surface. The one second reaction time and a braking rate of 0,6G is used for calculating the vertical curves over hills and through valleys to allow a safe stopping sight distance and to calculate where the solid white line must go where there is insufficient passing sight distance. When driving through a dip, the distance at which headlights will illuminate the next rise is also taken into account. Exceeding the design speed pushes the safety limits allowed in the calculations and can be fatal on wet or uneven road surfaces.
Many of our older roads were designed and built before the days of the blanket speed limit of 120 k.p.h. As a rough idea, our freeways were designed for a safe speed in good weather of 120 k.p.h. A road with single carriageways each way and tarred emergency lanes outside the yellow line probably has a designed speed of 100 k.p.h. When the road has a single carriageway in each direction and no hard emergency lane the designed speed is likely to be 80 k.p.h. All of this gives an idea of how far we are pushing safety limits at 120 k.p.h.
Town streets have to be built within the limits allowed by the terrain and the town planning layout and it is not always possible to design the streets to the in town speed limit and the designer has to depend on the good sense of drivers. Streets in industrial areas are designed for large trucks but sometimes residential areas become industrial areas and it needs extra care when turning at an intersection where there is also truck traffic.
Truck-trailer combinations have become longer and I have seen a few cars damaged when either the truck driver or the car driver forgot that then rear wheels of a combination take a much narrower curve than the front wheels in a tight turn. Usually the truck-trailer shows few signs that it has just squeezed a car down to 300mm narrower than the designers intended!
South Africa has not had a shining record among the general public in the field of mathematics. If you ask the average South African: “If a car travelling at 60 k.p.h. can stop in ten metres, how far will the stopping distance be at 120 k.p.h.?”, you will probably get the reply: “Twenty metres!” WRONG!! Energy increases as the square of the speed. Double the speed and stopping distance is 2X2 of the original because there is four times the amount of energy to be dissipated!!
Car design has improved over the years but they are not miracle machines. A passenger car of the fifties could stop from its maximum speed of 150 k.p.h. at 0,75G and a modern high performance passenger car may possibly stop from its top speed of 200 k.p.h. at 1,0G. This means that the modern car will take a third further to stop than the old timer! Again, energy increases as the square of the speed. Do our drivers realise that their modern speed machine can take further to stop at speed than Grandad’s old clunker when the old man was pushing it flat out?
How many South African know the details of the legislation allowing driving in the yellow emergency lane? In layman’s terms, the law specifies: IN DAYLIGHT HOURS and if he/she can see 150 metres and if he/she thinks it is safe to do so he/she may move into the emergency lane to allow another vehicle to pass. It is illegal to drive continuously in the emergency lane.
The emergency lane is designed only for broken down vehicles to stop in and is narrower than a standard high speed lane. The emergency lane is not designed to carry a large number of vehicles at speed and heavy trucks driving continuously in the yellow line are gradually destroying our roads. Because the emergency lane is narrower than a high speed lane, passing a vehicle driving in the emergency lane when there are two approaching vehicles doing the same thing is a recipe for disaster!
Why is South African time management so bad? In many prosperous countries people drive within the speed limits and still manage to make a good living. A relation of mine reduced her gear change points by 500 rpm and saved 20% on her fuel costs with NO INCREASE in trip time in city driving! So often in city driving someone passes me, weaving from lane to lane and braking late for traffic lights and ten kilometres later I find myself next to the same car at a traffic light. Who paid more and risked more in getting to the same place at the same time?
Road holding of cars has improved but how many drivers of certain SUV models and many rear wheel drive bakkies realise that their solid rear axle and leaf springs are of a design from more than 100 years ago! On an absolutely smooth surface the system is satisfactory but as soon as there is any irregularity in the road surface that rear suspension is a hundred years in the past and at excessive speeds the vehicle can quickly swap ends under heavy cornering or braking forces!
The modern SUV is a fine family vehicle, but beware of the “sports car” handling sometimes advertised! Because of its ability to carry anything from one person to six people and luggage, its weight distribution can vary from day to day and weight distribution affects handling. Beware also of advertisements that say you will “Own the road” in their car! Nobody from a Cabinet Minister to the lowliest driver owns the road.
I often see the boy racers racing on public roads late at night and I have seen collisions and near misses caused by braking at the wrong point and lack of knowledge in how to parabolise a bend. Safe high speed driving does not come just from having a licence and a few thousand kilometres of experience. Sweden has one of the lowest general speed limits in the world but they have a lot of very well organised very cheap and safe racing and they have produced some excellent racing and rally drivers.
It was raining hard late at night last year when I was driving in the middle lane of a three lane highway. I was three seconds behind the car in front of me and travelling at 100 k.p.h., which I considered to be the maximum safe speed in those conditions with visibility just good enough to see the tail lights of the car ahead clearly. In my mirror I saw a car coming up behind me at high speed and it ran through my mind: “You can see me, start your lane change.” Then: “You’re leaving it late!” The overtaking car moved into the outer lane and passed me but I saw that he had slid across the road until his right side wheels were on the grass of the median. I estimated his speed to be over 140 k.p.h. He was now about fifty metres ahead of me and running parallel to the road with two wheels on the tar. It ran through my mind: “You’ve got it straight, foot off the accelerator, don’t touch the brake and hold the wheel straight until it slows!” He was about eighty metres ahead of me when I saw his front wheel turn as he swung the steering wheel hard to his left. The car spun until it was facing the direction it was coming from, slid across the grass and flipped neatly over the median guardrail to land on its roof.
Conclusions: (a) Driving faster than road conditions allowed. (b) Leaving lane change too late. (c) Turning steering wheel suddenly at speed on wet grass. Three errors resulting in a nasty accident.
Three of us South Africans were walking in Hawaii and we came upon a highway with two lanes in each direction. There was a fuel station and shop on the opposite side of the road and traffic was light so we crossed the road. When we stepped onto the hard shoulder of the road, every car in sight stopped completely! Can you imagine putting one foot onto the edge of the tar and fifteen cars on a kilometre of road coming to a dead stop in this country?
A very pleasant Sikh taxi driver drove me from Broadway in New York to J.F.K. airport. The speed limit on the highway was 70 miles per hour and the road fairly busy. He drove at 71 miles per hour and no cars passed us!
Australia is a country similar to ours with busy cities and long distances. Twenty five road deaths over the Christmas season is considered a national disaster and with about twice the population we reach about a thousand! What is wrong with us?
A Canadian friend hired a car in Cape Town and drove to Knysna and back. The car hire firm had never seen so many dents on one of their cars! The same man drove from Canada to meet us in the south of Florida and there was not a scratch on his SUV.
We all know that we can safely chat on the cell ‘phone while driving in spite of the statistics proving otherwise, but texting while driving should be treated the same as drunken driving. Two famous text messages were: “I feel like a cup of coffee.” That one lead to the death of a mother and two children. The other was “I’m going to have breakfast at my next stop.” A train driver killed himself and twenty six other people with that one!
I am not going to discuss drunk driving but what about drugs? “Recreational” cannabis can be detected in a regular smoker for more than a week after he last smoked it! Is a person who smoked cannabis on Thursday capable of safe driving on Saturday night?
When we drive, a lot of our actions are subconscious. If we change gears, we don’t consciously think ‘push the clutch down, ease the accelerator, move the gear lever’ and so on. We decide to change gears and our subconscious mind does the rest. Why do so many drivers forget to indicate lane changes and corners? Drive for one week with a fixed determination to indicate every corner and lane change. After that you will never have to remember to indicate for a lane change or corner again. Your subconscious mind will move the indicator control when you decide to change lanes or turn a corner!
Why do so many drivers turn left at an intersection and the finish their turn in the right hand lane of the road they have turned into? It is illegal to change lanes in an intersection, and for a good reason! What about the driver who is coming from the right? Road design on intersecting roads with two lanes in each direction depends on drivers staying in their lanes in the intersection and then changing lanes if necessary on the straight.
I would love to know how many hours of my life I have wasted waiting to turn right at an intersection while a string of cars coming from the opposite side are turning left into the right hand lane and then moving into the left lane a hundred metres down the road to perform the same ridiculous process at the next intersection when I could happily have turned into the right hand lane! Very frustrating and frustration in impatient drivers can lead to fender benders, not to mention how correct procedures smooth traffic flow.
Can music affect our driving? Strangely enough, the answer is “Yes”!
Two Scottish bagpipers have received the Victoria Cross for playing their pipes under fire to raise the fighting spirit of the troops. One was shot through both ankles and the other got several bullet holes through his uniform but they carried on playing and the Highlanders won the day.
Before the Second World War, the Nazis knew the value of music in raising aggression.
Every Nazi rally had a band present and a continuous heavy bass drum beat was used to increase the aggressive spirit of the crowd.
Give a little extra space to a car that has loud music playing with a base beat that distorts the speakers and almost blows the windows out. It is likely to be aggressively driven.
Digital instrumentation is accurate and looks very modern but it takes more time to read than the old analogue dials. Because we spend our lives among buildings with vertical walls and vertical poles the human eye is very quick at recognising anything that is vertical. In the old four engine aircraft the flight engineer could check twenty instrument readouts in one second. If all of the needles were vertical he did not have to take note of any reading. If a needle was not vertical, he read that instrument and took action. How long does it take to read several numbers and then decide which one is showing a problem?
Of course, there is the red idiot light which tells you only that there is something wrong and no other information! I have had a red light come on for oil pressure but my pressure gauge told me it was a failure of the light’s sensor and I could drive on happily.
My ideal speedometer would one that picked up the local speed limit from the GPS and then adjusted the figures on the dial and the needle movement so that the speed limit was at the top of the dial and as long as the needle was vertical I was at the speed limit. Of course a further improvement would be that if I exceeded the limit by twenty kilometres per hour a loud voice would tell me that the car could be confiscated and crushed!
Lionel Latigan