Introduction and Importance of Safe Steering
In discussions about road safety, not much emphasis is placed on the safe steering of a vehicle. As this is often regarded as a “common sense” activity we seldom pay enough attention to the skills required to perform this safely!
Steering safely is a fundamental skill we learn when studying how to drive, and is perhaps the skill that most people associate with operating a vehicle.
Cars are designed to run straight on a level or even slightly cambered road. This means that, if you let go of the steering wheel on a level road, the car should continue in a straight line for some distance before gradually veering to the left, because of the natural road camber
Because it looks really simple, many drivers often pay no importance to steering safely. But don’t make that mistake; virtually all the other driving skills like parking, cornering, and overtaking rely heavily on one’s ability to steer in a fluid but precise manner. Many fatal head-on collisions are directly related to our failure to steer our vehicles safely!
In this section we would like to investigate how we can improve the ability to safely steer our vehicles in traffic!
Vehicle Maintenance and Safe Steering
To steer a vehicle requires not only the right technique and skills – but also roadworthiness of the vehicle and effective response from various vehicle components.
What are these vehicle components?
Vehicle components and factors which may affect steering include the following:
- Steering gear ratio and back lash: The steering gear provides mechanical advantage for the driver to guide the vehicle by exerting only a small amount of physical effort at the steering wheel.
- Steering linkage connection: They must provide free movement of the linkage to transmit driver’s effort at the steering wheel to the knuckles. If there is more play in the joints, most of the efforts shall be going waste and if there is less play, hard steering would result in.
- Type pressure: It should be as per specifications. Less or uneven pressure of air in the wheels shall result in hard steering and more tyre pressure shall lead to wobbling.
- Play in wheel bearings: The wheel bearing should be properly adjusted. Less play shall result in hard steering and more play shall effect wheel alignment and lead to wheel wander.
- Condition of king pins and bearings: The front portion vehicle load acts through the pins. If the pins are tight in the bushes, hard steering shall result in and if there is more play, wheel alignment shall be affected, which has great influence on the steering operation.
- Wheel alignment: this relates to the relative position of wheels for obtaining a true and free rolling movement over the road. The smooth operation of steering depends much upon the wheel alignment.
- Shock absorbers: Shock absorbers are filled with oil, which hydraulically dampen the suspension and prevent the wheels from bouncing. Due to this action, tyre-to-road contact is maintained over bumps and undulations. This in turn allows control of the vehicle to be maintained.
How can I diagnose what is wrong with the steering of my vehicle?
The best advice is to monitor how your vehicle steers on an open stretch of road. Check for the following:
- If the car wanders slightly from side to side during the test it may be due to incorrect, or uneven, wheel alignment, loose steering gear, or an uneven load.
- If the vehicle starts to deviate to one side the moment you let go of the wheel, it may be due to a major difference in tyre pressure between the left and right sides, improper rear wheel tracking, tyres not the same size, or a broken or sagged spring. It may also be a result of any of the faults mentioned in the previous paragraph.
- If you take a sharp corner and the steering wheel is reluctant to return to the straight-ahead position, or the steering requires too much effort, this may be due to low tyre pressure, binding steering linkages, damaged suspension arms, incorrectly adjusted steering gear or sagging front springs. A power-steering system might have a low fluid level, a defective pump, a sticky valve spool, a loose belt, or a kinked or clogged hose.
- If the steering wheel has excessive play, it will also have excessive kickback. This may be due to worn or loose steering linkages, a worn or badly adjusted steering box or improperly adjusted front-wheel bearings. Air in a power steering system could also result in excessive play.
- Tyre squeal on corners is usually due to low tyre pressure, but can also be caused by incorrect toe or camber.
Safety Advice: Have the ball joints on your steering system checked often. If you detect an oil leak on your vehicle, let somebody have a look at it, it might be your power steering fluid leaking. Although it is possible to steer a vehicle with the power steering not working, a sudden loss of power steering might be interpreted as a steering which do not respond.
Power Assisted Steering and Road Safety
Many older drivers learnt to drive before power assisted steering became the well-known feature in our modern cars. Nowadays few new vehicle owners will not insist on having power steering. But what is power steering?
Wikipedia has provided a brief summary:
Power steering helps the driver of a vehicle to steer by directing some of its power to assist in swivelling the steered road wheels about their steering axes. As vehicles have become heavier and switched to front wheel drive, particularly using negative offset geometry, along with increases in tire width and diameter, the effort needed to turn the wheels about their steering axis has increased, often to the point where major physical exertion would be needed were it not for power assistance. To alleviate this auto makers have developed power steering systems: or more correctly power-assisted steering—on road going vehicles there has to be a mechanical linkage as a fail-safe. There are two types of power steering systems; hydraulic and electric/electronic. A hydraulic-electric hybrid system is also possible.
A hydraulic power steering (HPS) uses hydraulic pressure supplied by an engine-driven pump to assist the motion of turning the steering wheel. Electric power steering (EPS) is more efficient than the hydraulic power steering, since the electric power steering motor only needs to provide assistance when the steering wheel is turned, whereas the hydraulic pump must run constantly.
In EPS, the amount of assistance is easily tuneable to the vehicle type, road speed, and even driver preference. An added benefit is the elimination of environmental hazard posed by leakage and disposal of hydraulic power steering fluid. In addition, electrical assistance is not lost when the engine fails or stalls, whereas hydraulic assistance stops working if the engine stops, making the steering doubly heavy as the driver must now turn not only the very heavy steering—without any help—but also the power-assistance system itself.
Driver Advice on Steering Safely
To steer the vehicle safely literally rests in both hands of the driver! A driver never knows when an emergency may arise and you owe it to yourself, the other passengers in your vehicle, and pedestrians as well as all the other drivers on the road to keep those hands on the wheel and get a grip on safe driving and safe steering!
We would like to provide a few suggestions to enhance safety:
- To have complete control of the car, the driver must be sitting in the correct comfortable position in relation to his size.
- Adjust your seat so that you may rest your hands comfortably on the steering wheel. Sitting too far back will force you to stretch your arms out that they’d tire easily, while sitting too near will leave little space for your arms to move—a dangerous situation when faced with challenging driving conditions.
- Challenging driver conditions would also include driving in strong wind, wet road surfaces etc.
- Always keep your eyes on the road, and hands on the wheel. Do not get distracted!
- Don’t forget to use your turn signals.
- When turning, your hand which is in the direction you are going should pull down while the other hand allows the wheel to pass through. When driving on rough terrain, the other hand can help by pushing the wheel upward to steer safely.
- Avoid crossing your arms over one another, as this limits your ability to adjust quickly.
- When transferring from one lane to another, or when pulling in after overtaking, the turn should be gradual and never a sudden swerve which may result in skidding.
Holding the Steering Wheel and Steering Safety
The positioning of the hands on the steering wheel is of the utmost importance for safe driving – and especially so when the driver has to respond in an emergency situation.
To effectively control your vehicle you must place both hands firmly on the steering wheel either in the 10&2 o'clock position or at 9&3 o'clock. And of course any position between those two would be a safe place to keep your hands.
We would like to share some very important insights from our Road Safety friends at Drive and Stay Alive. Drive and Stay Alive has urged drivers to ignore the latest fad for holding the steering wheel at the eight o'clock and four o'clock positions.
Some so-called experts are recommending 8 & 4 on the basis that it reduces the chance of injury if a collision occurs and the driver's airbag fires but this is highly inadvisable as it creates much more danger than it might eliminate.
It is perfectly true that the number of arm injuries has increased since the advent of airbags, but there are two very important points to be made:
- Holding the wheel at "8 & 4" not only encourages lazy driving, with the arms resting on the driver's thighs or lap, but it also significantly reduces a driver's ability to steer accurately and swiftly in the event of an emergency. Why else would the "10 & 2" or "9 & 3" positions have been recommended for so many decades in the first place?
Surely it is vastly preferable that a driver is able to respond accurately and promptly and thereby avoid a crash than it is to compromise this ability in the interests of possibly reducing arm injuries after a crash?
- The aforementioned increase in arm injuries (and related facial injuries, when the arms are smashed into a driver's face by an expanding airbag) is undoubtedly exacerbated by widespread use, in the USA, of "hand over" steering techniques (known elsewhere as crossing the arms). If the "push pull" (a.k.a. "shuffle") steering method is used instead of "hand over," then the chances of a driver getting one or even both arms smashed into his/her face by an airbag are reduced dramatically.
But the main thing is that avoiding a crash by holding and using the steering wheel properly is vastly preferable to having a crash while hopefully minimizing any arm injuries -- what about injuries to the rest of your body, to your passengers, and to other people on the road if you have a crash that could have been avoided? (That unhindered airbag isn't going to save everybody!)
Over Steer v Under Steer
What is referred to as Over Steering and Under Steering?
Under steer: The condition when, during cornering the vehicle continues, or tries to continue, in a straight line because the front tyres have reached the limit of their adhesion before the back tyres have.
Over steer: This is the opposite of under steer in that it is the rear of the vehicle that slides out when the limit of adhesion is reached while the front tyres are still gripping the road.
Driver Distractions and Safe Steering
You cannot control a car unless you have BOTH hands on the wheel. If you do not have those hands on the steering wheel you are not a safe driver! Accidents happen in milliseconds and you need to be prepared in the event of an emergency.
For example, say you are driving down the road and a child runs out in front of you. Your reaction is to swerve out of the way and avoid that child. If you happen to be driving with your knees or a finger or even just one hand, it will be impossible for you to safely turn the wheel. By the time you have put both hands on the wheel you will have already run over the poor child or lost control of your vehicle!
In South Africa where 30-40% of road fatalities are pedestrian deaths it is even more important to be alert at all times. We need to avoid driver distractions and anything that might deter us from having both hands on the steering wheel! This would include conversations while holding the cellular phone, texting while driving, eating etc.
Remain alert and vigilant on the roads at all times. If you believe that your vehicle is not steering 100% the manner it should rather consult with an expert!
Vehicle Maintenance, Repair and Road Safety
Shock Absorbers and Safety on the Road
Wheel Balance, Wheel Alignment and Road Safety
Avoiding Distractions while Driving
Road Safety and Tyre Safety