page 20 of 29 IN THIS NEXT SUB-SECTION, A DISCUSSION WILL BE MADE OF ROADWAY SAFETY ISSUES ABOUT THE EFFECTS OF TRACTION.
Traction is friction/adhesion between the tires and the road. Traction is needed for steering and braking purposes. However, there are some conditions that could reduce traction on the road. Some of these are slippery surfaces, hydroplaning, curves, hills, gravel roads, etc.
Slippery surfaces: Road surfaces become slippery when slightly melting ice will make ice wet. Wet ice is very slick, and when met, is very hard to control steering or to stop in a timely manner. Black ice is a thin layer of ice that allows you to see the road underneath it, watch out for black ice. As with wet ice, maneuverability becomes an issue. Bridges will freeze before roads when the temperature drops, because cold air flows against the bottom and the top of the bridge. Even wet roads from rain will become slick. In these conditions, your vehicle will take longer to stop and be harder to steer without skidding. If you do start skidding or sliding, steer in the direction of the skid, gently tapping your brakes until you regain control. It is always wise to slow down in these conditions, because the stopping time increases and steering mobility is lost.
Hydroplaning: This occurs when a layer of water builds up between the tires and the road surface, leading to a loss of traction and can lead to a catastrophic loss of steering. This could be likened to water skiing. It does not take a lot of water to cause hydroplaning. It could occur at speeds as low as 30 mph. The most dangerous point hydroplaning occurs when you come upon an unexpected ponding of water, and can panic the most experienced of drivers. Be sure to watch for ponding, and as with ice, steer in the direction of the slide, tapping your brakes.
Curves and hills: Many roads have curves and hills; however, the most dangerous of them are usually in rural areas with two lanes of traffic and trees or shrubs in the line of sight. This leads to a dangerous situation if you suddenly encounter another vehicle, and try to adjust your movement too quickly. When this happens, even on dry pavement, the sudden steering or stopping could cause you to skid out of control. This event could cause a rollover, and as with the above statements; steer with the skid, brake gently.
Gravel roads: There are many gravel roads in the country, and rural areas teem with them. When traveling fast, gravel can be just as treacherous as ice. Never travel past the posted limit on gravel roads. The same application of driving applies here as it does in the previous three statements. Steer into the skid and gently tap your brakes.
D. TOWING TECHNIQUES
The following section will contain an explanation of the tools and equipment, and the techniques of driving, while coming to, and working in an incident.
Tow truck equipment – light-duty trucks and car carriers
Tow trucks have four main parts to them, structure, booms, winches, and power systems.
– The structure generally refers to the fact of a truck having jacks in the rear in order to lift heavier loads.
– The power system of a tow truck may consist of one of three different systems,
1. An electrical system that is generally weaker than the other two, and the winch moves, but the boom does not move,
2. A mechanical system that operates the boom, and the winch – the great plus to this system is that it can work in all types of climates, and the maintenance costs are low,
3. A hydraulic system that usually works well than the other two, but cold climates dramatically reduce its effectiveness, and the upkeep costs are much higher.
– The boom is used to pick articles up and clear the body of your truck. Both mechanical and hydraulic booms can be moved up and down, and pulled out and in. The main difference between mechanical and hydraulic is that the booms on mechanical trucks are operated manually.
– Winches are applied to bring in articles and lift them free of the ground. There are also secondary winches on some trucks that will increase the amount of weight that can be applied at one point; these winches do not go over the boom.
Both booms and winches are used in conjunction with wheel lifts and straps, and tow slings.
Wheel lifts are used to haul a vehicle by the wheels, and when indicated, straps are used to keep the vehicle from coming out of the lift in adverse conditions,
Tow slings are used for cars, light trucks and vans, they may have one or two winch cables, and a snatch block and grab hooks are used along with them.
Tow trucks also have dollies in case it is needed to keep the towed vehicle
Entirely off the ground due to both axles being damaged, or it is a 4-wheel drive, or the wheels are locked in a position of inaccessibility.
There are three types of dollies:
1. Jack-up dollies that have to use another jack to lift the vehicle,
2. Pan dollies that go under the trailing wheels,
3. And self-loading dollies that get the vehicle into the proper position without the use of other equipment.
Car carriers are used to, as the name indicates, to carry vehicles on a bed behind the cab of the truck. The bed tilts up, after being moved back about a foot, then the bed is lowered to the ground. Then straps or chains with hooks are attached to the proper points of the vehicle. Then the vehicle is winched onto the bed and it lowered back down.
A point to remember is that all towed vehicles should be secondarily chained or strapped into place at four points, in addition to the drawbar, tongue, or other device.
Other parts that tow trucks and carriers have are as follows:
– Chains are an integral part of the towing system, and they are broken down into several categories, uses, and strengths;
– Tie-down chains are at the four opposing corners of a carrier
– Secondary chains or safety chains are employed for use on tow trucks in conjunction with wheel lifts and slings,