Subsections 2.2 and 2.3  Test Your Knowledge  2.3.2 – Multi-speed Rear Axles and  Auxiliary Transmissions  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.  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.  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.  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.  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.  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.  All drivers look ahead; but many don't look far  enough ahead.  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.  These questions may be on the test. If you can't  answer them all, re-read subsections 2.2 and 2.3.  2.3.3 – Automatic Transmissions  2.3.4 – Retarders  2.4.1 – Seeing Ahead  1.  Why should you back toward the driver's side?  2. If stopped on a hill, how can you start moving  without rolling back?  3. When backing, why is it important to use a  helper?  4. What's the most important hand signal that you  and the helper should agree on?  5. What are the two special conditions where you  should downshift?  6. When should you downshift automatic transmissions?  7. Retarders keep you from skidding when the  road is slippery. True or False?  8.  What are the two ways to know when to shift?  2005 Model Commercial Driver’s License Manual 2.4 – Seeing  Page 2-10 Section 2 – Driving Safely 