General Knowledge: Communication
22 questions in the bank cover this topic. Everything below is drawn from the sources those questions cite.
Sources: 49 CFR 392.22, 49 CFR 393.25, TC 21-305-20 para 2-4, TC 21-305-20 para 2-5, TC 21-305-20 para 2-6, TC 21-305-20 para 2-9, TC 21-305-20 para 3-58, TC 21-305-20 para 6-7
What you need to know
392.22(a) requires the hazard warning flashers to be activated immediately and kept flashing until the warning devices are placed.
The flashers are also used again while the devices are being collected before moving off.
Whenever a commercial motor vehicle is stopped upon the traveled portion of a highway or the shoulder of a highway for any cause other than necessary traffic stops, the driver of the stopped commercial motor vehicle shall immediately activate the vehicular hazard warning signal flashers and continue the flashing until the driver places the warning devices required by paragraph (b).
49 CFR 392.22
392.22(b)(1) requires placement as soon as possible but in any event within 10 minutes.
the driver shall, as soon as possible, but in any event within 10 minutes, place the warning devices required by § 393.95 of this subchapter
49 CFR 392.22
392.22(b)(1) specifies one device 10 feet (4 paces) on the traffic side toward approaching traffic, one at 100 feet (40 paces) toward approaching traffic, and one at 100 feet away from approaching traffic.
One goes toward approaching traffic and one away from it, both in the center of the lane or shoulder you occupy.
(i) One on the traffic side of and 4 paces (approximately 3 meters or 10 feet) from the stopped commercial motor vehicle in the direction of approaching traffic; (ii) One at 40 paces (approximately 30 meters or 100 feet) from the stopped commercial motor vehicle in the center of the traffic lane or shoulder occupied by the commercial motor vehicle and in the direction of approaching traffic; and (iii) One at 40 paces (approximately 30 meters or 100 feet)
in the direction away from approaching traffic.
49 CFR 392.22
392.22(b)(2)(v) sets 200 feet and 100 feet toward approaching traffic, plus one device on the traffic side within 10 feet of the rear of the vehicle.
Plus one within 10 feet of the rear on the traffic side.
If a commercial motor vehicle is stopped upon the traveled portion or the shoulder of a divided or one-way highway, the driver shall place the warning devices
one warning device at a distance of 200 feet and one warning device at a distance of 100 feet in a direction toward approaching traffic
shall place one warning device at the traffic side of the commercial motor vehicle within 10 feet of the rear of the commercial motor vehicle.
49 CFR 392.22
392.22(b)(2)(iv) requires placement 100 to 500 feet from the vehicle in the direction of the obstruction, far enough to give other road users ample warning.
Placed in the direction of the obstruction to view.
If a commercial motor vehicle is stopped within 500 feet of a curve, crest of a hill, or other obstruction to view, the driver shall place the warning signal
in the direction of the obstruction to view a distance of 100 feet to 500 feet from the stopped commercial motor vehicle so as to afford ample warning to other users of the highway.
49 CFR 392.22
392.22(b)(2)(vi) prohibits lighting or placing any flame-producing emergency signal except at a distance from the leaking liquid or gas that will assure prevention of fire or explosion.
They must not be lit or placed any closer than that.
If gasoline or any other flammable liquid, or combustible liquid or gas seeps or leaks from a fuel container or a commercial motor vehicle stopped upon a highway, no emergency warning signal producing a flame shall be lighted or placed except at such a distance from any such liquid or gas as will assure the prevention of a fire or explosion.
49 CFR 392.22
393.25(a) allows temporary lamps on the load.
The point is that whatever is actually the rearmost part of your vehicle has to be lit, even if that part is the cargo.
Temporary lamps must be securely mounted to the load and are not required to be mounted to a permanent part of the vehicle.
49 CFR 393.25
The pedestrian, where there are no lights.
Right of way is something you give rather than something you take, and nothing about your size changes that.
Pedestrians have the right-of-way where there are no traffic lights.
TC 21-305-20 para 6-7
Stop, and remain stopped until the crossing is complete.
The rule is absolute because the pedestrian cannot see you creeping forward and has only sound to judge you by, so a horn is the wrong answer twice over.
When a blind pedestrian enters an intersection, all approaching vehicles must stop and must remain stopped until the blind pedestrian has completed crossing.
TC 21-305-20 para 6-7
Let them finish.
A green light gives you permission to go when it is safe, not a right to the space somebody is still occupying.
If a light changes to yellow or red while crossing, operators must allow them to complete crossing safely.
TC 21-305-20 para 6-7
The pedestrian signal takes precedence for them.
Knowing this tells you when to expect people in the road: it can be their turn to walk while your light is still green.
Where these lights are in operation, pedestrians must obey them rather than the traffic lights.
TC 21-305-20 para 6-7
They say 'I am stopped and should not be', which is why using them while moving slowly muddies a signal other drivers rely on.
Not when parked where you belong.
Four-way emergency flashers are used to warn motorists that a vehicle has come to a stop due to an emergency in a traffic lane or on the shoulder adjacent to a traffic lane.
TC 21-305-20 para 2-9
No.
A vehicle parked where it belongs is not a hazard, and flashers used there teach other drivers to ignore them where they matter.
When a vehicle halts in an authorized space, emergency flashers are not normally used.
TC 21-305-20 para 2-9
Yes.
Flashers depend on the electrical system that may have just failed, and they do not give approaching traffic the distance that a triangle set 100 feet back does.
Four-way emergency flashers are not a substitute for warning devices contained in the highway warning kit.
TC 21-305-20 para 2-9
100 feet, and the manual calls it a minimum rather than a target.
The faster you are going, the earlier you should signal.
The law usually requires you to signal at least 100 feet in advance (this is the minimum distance).
TC 21-305-20 para 2-4
Worthless, because the signal's whole job is to let others act before you do.
A signal that arrives with the maneuver is a description, not a warning.
If you do not signal until you have already started to turn or stop, you might as well not signal.
TC 21-305-20 para 2-4
At least your own stopping distance.
If you signal later than that, a driver behind who reacts to your signal still cannot stop in time.
Your signaling distance should never be less than the distance required for stopping
TC 21-305-20 para 2-4
Down, palm back.
Hand signals matter when your lights have failed, which is also when you most need other drivers to understand you.
The signal for stopping and slowing down is given by pointing the arm and hand down, palm back.
TC 21-305-20 para 2-5
Up from the elbow.
Straight out is left, down is stopping. All three are given with the left arm, since that is the one at a window in a left-hand drive vehicle.
The left turn signal is given by pointing the arm and hand straight out, palm forward. The right turn signal is given by pointing the arm and hand straight up from the elbow, palm forward.
TC 21-305-20 para 2-5
An arm hanging out of a window looks like a signal to anyone behind you.
You communicate whether you mean to or not, so the warning is to control what you are saying. You communicate whether you mean to or not. You communicate whether you mean to or not.
Make your signals clearly and pay attention to your “body” language to ensure that you do not inadvertently give misleading signals to other drivers.
TC 21-305-20 para 2-6
At least 100 feet, the same minimum that applies to any signalled maneuver.
None of the figures offered is the one the rule gives.
Before making any turn, always signal at least 100 feet before the intersection.
TC 21-305-20 para 3-58
Move your own head to restore the sight line.
Delegating the look to a passenger makes them responsible for a judgment only you can make.
When making a left turn, ensure that traffic approaching from the right is visible). If there is a passenger in the front seat, lean forward to obtain a better view of traffic.
TC 21-305-20 para 3-58
Check yourself
- How do you respond first when your vehicle breaks down on the shoulder?
- What must you do within ten minutes of stopping on the travelled way?
- On a two-lane, two-way road, where does the rule require the three warning devices to be placed?
- What warning device placement is required on a divided or one-way highway?
- Where must a warning device go when you stop near the crest of a hill?
- What two warning device rules apply where fuel is leaking?
- What is allowed for a load projecting beyond the rear of your trailer?
- Who has right of way at an unsignalled intersection with a pedestrian crossing?
- How should you act when a blind pedestrian enters an unsignalled intersection?
- How should you act when your light turns green while a pedestrian is still crossing?
- At an intersection with special pedestrian signals, which signal governs pedestrians?
- When are four-way flashers meant to be used?
- What should you do with the flashers when parked in an authorized space?
- What must you still do after a breakdown even with flashers on?
- How far in advance does the law usually require you to signal?
- What is the manual's rule on signaling only as you begin the turn?
- What floor does the manual put on your signaling distance?
- What two elements make up the hand signal for stopping or slowing?
- Which hand signal means a right turn?
- Why does the manual warn about resting your elbow out of the window?
- How far before the intersection must you signal a turn?
- What should you do when a passenger blocks your view for a left turn?
Answers are in the practice test for this topic.