Section 2.3 - 2.4

 2.3 Shifting Gears

Correct shifting of gears is important. If you can't get your vehicle into the right gear while driving, you will have less control.

2.3.1 Manual Transmissions

Basic Method for Shifting Up.

Most heavy vehicles with manual transmissions require double clutching to change gears. This is the basic method:

• Release accelerator, push in clutch and shift to neutral at the same time.
• Release clutch.
• Let engine and gears slow down to the rpm required for thenextgear (this takes practice).
• Push in clutch and shift to the higher gear at the same time.
•  Release clutch and press accelerator at the same time.

Shifting gears using double clutching requires practice. If you remain too long in neu­tral, you may have difficulty putting the vehicle into the next gear. If so, don't try to force it. Re­turn to neutral, release clutch, increase engine speed to match road speed, and try again.

Knowing When to Shift Up.

There are two ways of knowing when to shift:

• Use Engine Speed (rpm). Study the driver's manual for your vehicle and learn the operating rpm range. Watch your tachometer, and shift up when your engine reaches the top of the range. (Some newer vehicles use "progressive" shift­ing: the rpm at which you shift becomes higher as you move up in the gears. Find out what's right for the vehicle you will operate.)
• Use Road Speed (mph). Learn what speeds each gear is good for. Then, by using the speedometer, you'll know when to shift up.

With either method, you may learn to use engine sounds to know when to shift.

Basic Procedures for Shifting Down

• Release accelerator, push in clutch, and shift to neutral at the same time.
• Release clutch.
• Press accelerator, increase engine and gear speed to the rpm required in the lower gear.
• Push in clutch and shift to lower gear at the same time.
• Release clutch and press accelerator at the same time.
• Downshifting, like upshifting, requires knowing when to shift. Use either the ta­chometer or the speedometer and downshift at the right rpm or road speed.

Special conditions where you should downshift are:

• Before Starting Down a Hill. Slow down and shift down to a speed that you can control without using the brakes hard. Otherwise the brakes can overheat and lose their braking power. Downshift before starting down the hill. Make sure you are in a low enough gear, usually lower than the gear required to climb the same hill.
• Before Entering a Curve. Slow down to a safe speed, and downshift to the right gear before entering the curve. This lets you use some power through the curve to help the vehicle be more stable while turning. It also allows you to speed up as soon as you are out of the curve.

2.3.2 Multi-speed Rear Axles and Auxiliary Transmissions

Multi-speed rear axles and auxiliary trans­missions are used on many vehicles to provide extra gears. You usually control them by a selector knob or switch on the gearshift lever of the main transmission. There are many different shift patterns. Learn the right way to shift gears in the vehicle you will drive.

2.3.3 Automatic Transmissions

Some vehicles have automatic transmissions. You can select a low range to get greater engine braking when going down grades. The lower ranges prevent the transmission from shifting up beyond the selected gear (unless the governor rpm is exceeded). It is very important to use this braking effect when going down grades.

2.3.4 Retarders

Some vehicles have "retarders." Retarders help slow a vehicle, reducing the need for using your brakes. They reduce brake wear and give you another way to slow down. There are four basic types of retarders (exhaust, engine, hy­draulic, and electric). All retarders can be turned on or off by the driver. On some vehicles the retarding power can be adjusted. When turned "on," retarders apply their braking power (to the drive wheels only) whenever you let up on the accelerator pedal all the way.

Because these devices can be noisy, be sure you know where their use is permitted.

Caution. When your drive wheels have poor traction, the retarder may cause them to skid. Therefore, you should turn the retarder off whenever the road is wet, icy, or snow covered.

Caption

Figure 2.6: In city driving, 2 to 15 seconds is about one block or in highway driving, it is about a quarter of a mile

2.4 Seeing

To be a safe driver you need to know what's going on all around your vehicle. Not looking properly is a major cause of accidents.

2.4.1 Seeing Ahead

All drivers look ahead; but many don't look far enough ahead.

Importance of Looking Far Enough Ahead.

Because stopping or changing lanes can take a lot of distance, knowing what the traffic is doing on all sides of you is very important. You need to look well ahead to make sure you have room to make these moves safely.

How Far Ahead to Look.

Most good drivers look at least 12 to 15 seconds ahead. That means looking ahead the distance you will travel in 12 to 15 seconds. At lower speeds, that's about one block. At highway speeds it's about a quarter of a mile. If you're not looking that far ahead, you may have to stop too quickly or make quick lane changes. Looking 12 to 15 seconds ahead doesn't mean not paying attention to things that are closer. Good drivers shift their attention back and forth, near and far. Figure 2.6 illustrates how far to look ahead.

Look for Traffic.

Look for vehicles coming onto the highway, into your lane, or turning. Watch for brake lights from slowing vehicles. By seeing these things far enough ahead, you can change your speed, or change lanes if necessary to avoid a problem. If a traffic light has been green for a long time it will probably change before you get there. Start slowing down and be ready to stop.

2.4.2 Seeing to the Sides and Rear

It's important to know what's going on behind and to the sides. Check your mirrors regu­larly. Check more often in special situations.

Mirror Adjustment.

Mirror adjustment should be checked prior to the start of any trip and can only be checked accurately when the trailer(s) are straight. You should check and adjust each mirror to show some part of the vehicle. This will give you a reference point for judging the position of the other images.

Regular Checks.

You need to make regular checks of your mirrors to be aware of traffic and to check your vehicle.

Traffic.

Check your mirrors for vehicles on either side and in back of you. In an emergency, you may need to know whether you can make a quick lane change. Use your mirrors to spot overtaking vehicles. There are "blind spots" that your mirrors cannot show you. Check your mirrors regularly to know where other vehicles are around you, and to see if they move into your blind spots.

Caption

Figure 2.7

Check Your Vehicle.

Use the mirrors to keep an eye on your tires. It's one way to spot a tire fire. If you're carrying open cargo, you can use the mirrors to check it. Look for loose straps, ropes, or chains. Watch for a flapping or bal­looning tarp.

Special Situations.

Special situations require more than regular mirror checks. These are lane changes, turns, merges, and tight maneuvers.

Lane Changes.

You need to check your mirrors to make sure no one is alongside you or about to pass you. Check your mirrors:

• Before you change lanes to make sure there is enough room.
• After you have signaled, to check that no one has moved into your blind spot.
• Right after you start the lane change, to double-check that your path is clear.
• After you complete the lane change.

Tums.

In turns, check your mirrors to make sure the rear of your vehicle will not hit anything.

Merges.

When merging, use your mirrors to make sure the gap in traffic is large enough for you to enter safely.

Tight Maneuvers.

Any time you are driving in close quarters, check your mirrors often. Make sure you have enough clearance.

How to Use Mirrors.

Use mirrors correctly by checking them quickly and understanding what you see.

• When you use your mirrors while driving on the road, check quickly. Look back and forth between the mirrors and the road ahead. Don't focus on the mirrors fortoo long. Otherwise, you will travel quite a distance without knowing what's happening ahead.
• Many large vehicles have curved (convex, "fisheye," "spot," "bugeye") mirrors that show a wider area than flat mirrors. This is often helpful. But everything appears smaller in a convex mirror than it would if you were looking at it directly. Things also seem farther away than they really are. It's important to realize this and to allow for it. Figure 2.7 shows the field of vision using a convex mirror.