Did A Practice And This Made No Sense...

3. Three things factor into how quickly you can come to a full stop; those are: a) Perception distance, response distance, reaction distance. b) Perception distance, reaction distance, braking distance. c) Observation distance, reaction distance, slowing distance. d) Road conditions, speed, perception distance. Incorrect.

I choose D as if the roads are slick and you're going faster or slower that can dramatically change your ability to stop... they said it was B? Whats your knowledge/opinion on the subject?

3. Three things factor into how quickly you can come to a full stop; those are: a) Perception distance, response distance, reaction distance. b) Perception distance, reaction distance, braking distance. c) Observation distance, reaction distance, slowing distance. d) Road conditions, speed, perception distance. Incorrect.

I choose D as if the roads are slick and you're going faster or slower that can dramatically change your ability to stop... they said it was B? Whats your knowledge/opinion on the subject?

While i agree weather conditions and speed have a role to play, you should be adjusting speed accordingly for the weather. Thus the question of what relates to stopping distance becomes:how fast you recognize a problem, how fast can you react to the problem, and how fast the truck can stop....perception, reaction, braking distance.

That's how I see this question anyways.

3. Three things factor into how quickly you can come to a full stop; those are: a) Perception distance, response distance, reaction distance. b) Perception distance, reaction distance, braking distance. c) Observation distance, reaction distance, slowing distance. d) Road conditions, speed, perception distance. Incorrect.

I choose D as if the roads are slick and you're going faster or slower that can dramatically change your ability to stop... they said it was B? Whats your knowledge/opinion on the subject?

While i agree weather conditions and speed have a role to play, you should be adjusting speed accordingly for the weather. Thus the question of what relates to stopping distance becomes:how fast you recognize a problem, how fast can you react to the problem, and how fast the truck can stop....perception, reaction, braking distance.

That's how I see this question anyways.

That makes sense like it could have been a trick question that is to say situational awareness supersedes an idiot in a situation

What they're trying to do is help people understand the factors that affect total stopping distance by dividing them into three general factors - perception distance, reaction distance, and braking distance. Every possibility will fall under one of those three categories.

From Controlling Vehicle Speed in our High Road Training Program:

• Perception distance is the distance your vehicle travels from the time your eyes see a hazard until your brain recognizes it. The perception time for an alert driver is about 3/4 second. At 55 mph, you travel 60 feet in 3/4 second.
• Reaction distance is the distance traveled from the time your brain tells your foot to move from the accelerator until your foot is actually pushing the brake pedal. The average driver has a reaction time of 3/4 second. This accounts for an additional 60 feet traveled at 55 mph.
• Braking distance is the distance it takes to stop once the brakes are applied. At 55 mph on dry pavement with good brakes, it can take a heavy vehicle about 170 feet and about 4 1/2 seconds to stop.

For example:

If you're texting instead of watching the road that's going to increase your perception distance - it took you longer to perceive the problem so you're travelling farther because of this.

If your feet are up on the dashboard cuz you're cool like that it's going to lengthen your reaction distance because it takes you longer to get your feet from on top of the dash to the brake pedal.

If the roads are slick or you're loaded heavy it's going to lengthen your braking distance because you can't stop as quickly under those circumstances.

So they're trying to help you understand the various factors involved with total stopping distance by putting them into three separate categories.

3. Three things factor into how quickly you can come to a full stop; those are: a) Perception distance, response distance, reaction distance. b) Perception distance, reaction distance, braking distance. c) Observation distance, reaction distance, slowing distance. d) Road conditions, speed, perception distance. Incorrect.

I choose D as if the roads are slick and you're going faster or slower that can dramatically change your ability to stop... they said it was B? Whats your knowledge/opinion on the subject?

True it will effect your ability to stop. Road conditions and speed are contributing factors and will either increase or decrease overall perception distance, reaction distance, and braking distance. B is the correct and best choice.

The greater the speed, the greater the distance travelled becomes for all 3; perception, reaction, and braking. If the roads are slick or snow covered, braking distance is increased. If there is fog or other factors limiting visibility, perception distance is longer. Etc.

This is why reducing speed and increasing following distance (time) are such important elements of safely dealing with road conditions (traffic congestion, weather, construction).

For further detail you could reference the CDL Training Manual, page 19, found on this website.

As a school teacher I also taught "test taking strategy" for those multiple choice test you take in April & May.

If one of the answers has a judgement or an explanation in the answer, it's probably wrong. Your choice:

d) Road conditions, speed, perception distance.

Has "Road conditions" which can be a judgement call.

The correct answer:

b) Perception distance, reaction distance, braking distance.

can be staked out on the road and measured. The other two answers contain terms (response & observation) that aren't part of the discussion.

This is a nuts & bolts way to game out a test, and might prove useful on these CDL answer sets.

In our exams they also account for "brake lag" time.

Traction, or lack thereof effects braking distance, and is simply a factor thereof, not a separate entity.

Phil