Traffic Laws, Signs, Signals, and Road Markings
What you must know
Commercial driving law rests on a predictable hierarchy: a uniformed officer's direction outranks a signal, a signal outranks a sign, and a sign outranks a painted marking. Learn the sign families by shape and color, because exam questions often describe a sign without naming it. Octagons mean stop; inverted triangles mean yield; diamonds warn; pennants mark no-passing zones; round signs mark railroad crossings; rectangles carry regulatory or guide information. Colors carry meaning too: red for prohibitions, yellow for warnings, orange for construction and maintenance, fluorescent pink for incident management, green for guidance, blue for services, brown for recreation and points of interest.
Markings are equally testable. A solid yellow line means no passing from your side; a broken yellow line permits passing when safe; double solid yellow forbids passing in both directions. White lines separate traffic moving the same way, with broken white indicating lane changes are allowed. Edge lines and crosswalks have specific rules, and a shared center turn lane is for turning only, never for travel or passing.
Traps to expect
Questions love near-misses: yielding at a four-way stop when two vehicles arrive simultaneously (the vehicle on the right goes first, but a vehicle already in the intersection has the right of way); treating a flashing yellow as a stop (it is caution, not stop); confusing a flashing red (treat as a stop sign) with a solid red (full stop, then proceed only when permitted). School-zone and work-zone speed limits apply when posted or when workers or children are present, depending on the jurisdiction.
Rule of thumb: when two rules seem to conflict, the more restrictive or more immediate instruction controls. Officer over signal, signal over sign, sign over marking, and specific posted limits over general defaults.