Road Signs: Warning Signs

11 questions in the bank cover this topic. Everything below is drawn from the sources those questions cite.

Sources: MUTCD 11th Ed. Section 2B.41, MUTCD 11th Ed. Section 2C.14, MUTCD 11th Ed. Section 2C.15, MUTCD 11th Ed. Section 2C.16, MUTCD 11th Ed. Section 2C.64

What you need to know

2C.14 ties the sign to a downgrade whose length, grade, curvature or other features require special precautions.

It is a warning about what the hill demands of you, not a statement that a hill exists.

The Hill (W7-1) sign (see Figure 2C-5) should be used in advance of a downgrade where the length, percent of grade, horizontal curvature, and/or other physical features require special precautions on the part of road users.

MUTCD 11th Ed. Section 2C.14

2C.14 lists a threshold per grade: 5 percent over 3,000 ft, 6 percent over 2,000 ft, 7 percent over 1,000 ft, 8 percent over 750 ft and 9 percent over 500 ft.

The steeper the grade, the shorter it has to be before the sign is warranted.

6% grade that is more than 2,000 feet in length,

MUTCD 11th Ed. Section 2C.14

The list runs the other way to the intuition: a 9 percent grade qualifies after only 500 ft, while a 5 percent grade needs more than 3,000 ft.

9% grade that is more than 500 feet in length.

MUTCD 11th Ed. Section 2C.14

2C.14 says the plaque marks a situation where downshifting AS WELL AS braking might be advisable.

It is added to the Hill sign, so it is telling you how to take the grade.

A USE LOW GEAR (W7-2P) or TRUCKS USE LOWER GEAR (W7-2bP) supplemental plaque (see Figure 2C-5) may be used to indicate a situation where downshifting as well as braking might be advisable.

MUTCD 11th Ed. Section 2C.14

2C.64 puts them at approximately 1-mile spacing, so the sign keeps telling you how much grade is left rather than announcing it once and going quiet.

On longer grades, the use of a distance (W7-3aP or W7-3bP) plaque (see Figure 2C-5) at periodic intervals of approximately 1-mile spacing should be considered.

MUTCD 11th Ed. Section 2C.64

2C.15 puts advance warning at approximately 1 mile and again at approximately half a mile, with a further sign at the gore.

You are told three times, because a driver who needs the ramp has no time to decide.

truck escape (or runaway truck) ramp advance warning signs (see Figure 2C-5) should be located approximately 1 mile and approximately

MUTCD 11th Ed. Section 2C.15

This is one of the few hill provisions written as a Standard rather than Guidance, so shall, not should.

A ramp without its sign is not a ramp anyone can find in time.

When truck escape ramps are installed, at least one of the W7-4 series signs shall be used.

MUTCD 11th Ed. Section 2C.15

2C.15 uses the plaque to describe the ramp surface.

Surface is what decides how the ramp stops you, so it is worth reading on the way down rather than at the entrance.

A SAND (W7-4dP), GRAVEL (W7-4eP), or PAVED (W7-4fP) supplemental plaque (see Figure 2C-5) may be used to describe the ramp surface.

MUTCD 11th Ed. Section 2C.15

2B.41 gives the purpose as discouraging other road users from entering.

A car parked on an escape ramp is an obstacle in the one place a loaded truck cannot steer around.

A RUNAWAY VEHICLES ONLY (R4-10) sign (see Figure 2B-10) should be installed near a truck escape (or runaway truck) ramp entrance to discourage other road users from entering the ramp.

MUTCD 11th Ed. Section 2B.41

2C.16 ties it to inadequate stopping sight distance at the posted speed limit over a crest.

The hill is not the hazard. What you cannot see beyond it is.

A HILL BLOCKS VIEW (W7-6) sign (see Figure 2C-5) may be used on the approach to a crest vertical curve where the vertical curvature provides inadequate stopping sight distance at the posted speed limit.

MUTCD 11th Ed. Section 2C.16

2C.16 derives the advisory speed from available stopping sight distance, which is why it can be well under the posted limit on a crest that looks harmless.

it should be supplemented by an Advisory Speed (W13-1P) plaque (see Figure 2C-1) indicating the recommended speed for traveling over the hillcrest based on available stopping sight distance.

MUTCD 11th Ed. Section 2C.16

Check yourself

• What is the Hill sign warning you about ahead?

• At what length does a 6 percent grade call for the Hill sign?

• Which pairing of grade and length warrants the Hill sign?

• What does a TRUCKS USE LOWER GEAR plaque tell you?

• How often do you pass a distance plaque on a long grade?

• How far ahead of an escape ramp are you first warned?

• What must be posted wherever a truck escape ramp is installed?

• What does a SAND or GRAVEL plaque under an escape ramp sign tell you?

• What is a RUNAWAY VEHICLES ONLY sign for?

• What is a HILL BLOCKS VIEW sign warning you about?

• What is the advisory speed you are given on a blind crest based on?

Answers are in the practice test for this topic.