Regulatory Signs: Speed, Stop/Yield, Lane Use, Turn and Parking Controls
Regulatory signs tell you what you must or must not do. The Missouri exam tests both recognition and the required driver action. Most are red-and-white or white-and-black, and they stay in force until another sign, signal, or pavement marking changes them.
Core rules
- Speed limits are maximums for ideal conditions, not targets. A posted 55 means 55 or less; a minimum-speed sign sets a floor. The limit ends at an "END SPEED LIMIT" sign or the next posted limit.
- Stop is the octagon. Stop before the stop line, crosswalk, or edge of the intersecting roadway, then yield to pedestrians and cross traffic. At a four-way stop, first arrival goes first; if two arrive together, the driver on the right yields.
- Yield is the inverted triangle. Slow and stop only if necessary to let cross traffic or pedestrians pass.
- Lane-use signs and arrows require you to turn from the marked lane. A center lane marked with left-turn arrows in both directions is a two-way left-turn lane, not a through lane.
- Turn and parking signs prohibit specific movements or stopping. Right turn on red is allowed in Missouri after a full stop unless a sign says otherwise.
Worked example
A driver at a red light wants to turn right, but a "NO TURN ON RED" sign is mounted beside the signal. The general Missouri permission does not apply: the driver must stop and wait for a green arrow or green light, then turn when clear.
Traps
A rolling stop scores as no stop. A yield sign is not a stop sign unless traffic requires it. Turn-only arrows bind you once you enter the lane, and parking signs can apply from the sign to the corner even when the curb looks open.