Passenger: Mirrors

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

Sources: 49 CFR 571.111

What you need to know

FMVSS 111 S7.1 requires flat, unit magnification mirrors of at least 323 square centimetres on both sides, adjustable horizontally and vertically, giving a view to the rear along both sides.

They must be on stable supports. None of the figures offered is the one the rule gives.

each bus, other than a school bus, with a GVWR of more than 4,536 kg shall have outside mirrors of unit magnification, each with not less than 323 cm

49 CFR 571.111

FMVSS 111 S5.4.2 requires that exact wording, permanent and indelible, at the lower edge, in letters between 4.8 and 6.4 mm.

A convex mirror shows more but makes everything look further away. It must be permanently marked at the lower edge of the reflective surface.

Each convex mirror shall have permanently and indelibly marked at the lower edge of the mirror's reflective surface, in letters not less than 4.8 mm nor more than 6.4 mm high the words “Objects in Mirror Are Closer Than They Appear.”

49 CFR 571.111

FMVSS 111 S4 defines it as a plane or flat mirror with no size distortion.

That is what makes distance judgment reliable in it, and why a convex mirror needs the warning marking instead. The image is the same angular size as the object seen directly.

Unit magnification mirror means a plane or flat mirror with a reflective surface through which the angular height and width of the image of an object is equal to the angular height and width of the object when viewed directly at the same distance

49 CFR 571.111

Check yourself

• What are the outside mirrors your bus over 4,536 kg GVWR must have?

• What is the marking required on a convex mirror, and where does it go?

• A unit magnification mirror is ______.

Answers are in the practice test for this topic.