On a straight, level, undivided two-lane road, how should three reflective triangles be placed around a stopped commercial vehicle?
Correct answer: A. – One within 10 feet on the traffic side, one about 100 feet ahead, and one about 100 feet behind
On a two-way undivided road, federal rules require one warning device on the traffic side within ten feet of the vehicle. The other two are placed about 100 feet ahead of and 100 feet behind the stopped vehicle. The Alaska manual illustrates this arrangement because approaching traffic may come from either direction.
Source: Alaska Commercial Driver License Manual — § 2.5.2, “Communicating Your Presence”, 49 CFR § 392.22(b)(1) – Emergency signals; stopped commercial motor vehicles

