Regulatory Signs: Speed Limits, STOP, YIELD, Prohibitions and Mandatory Directions
Regulatory signs carry legal force, and this domain tests whether you can read them quickly and tell a rule from a recommendation. On the Colorado knowledge test you will meet speed limits, STOP, YIELD, prohibition signs and mandatory-direction signs, often mixed with warning signs that look similar but have no legal weight.
Speed limits
Colorado applies the basic speed law on top of posted limits: never faster than is reasonable and prudent for conditions, even below the posted number. Where no limit is posted, statutory defaults apply - 30 mph in residential districts, 25 mph in business districts and 20 mph in school zones. Rural interstate segments are posted as high as 75 mph; urban freeway segments are commonly 65 mph or lower. A SPEED ZONE AHEAD sign announces a change but does not itself set the limit; the new number begins at the sign that carries it.
STOP and YIELD
A STOP sign requires a complete halt at the stop line; if there is none, at the crosswalk; if there is none, at the edge of the roadway - the first of these you reach. After stopping, Colorado allows a right turn on red unless a sign prohibits it, and a left turn on red from a one-way street onto another one-way street. YIELD does not demand a stop unless traffic, pedestrians or sight distance require one.
Prohibitions and mandatory movements
A red circle with a slash means the symbol inside is prohibited (no U-turn, no left turn, no trucks). Mandatory-direction signs give the only legal movement - a white arrow on black, or a black arrow on white - and symbol signs for turn lanes or bike lanes define where you must be.
Worked example
A rural Colorado highway is posted 65 mph. Four hundred feet later a yellow diamond shows a curve with a 40 MPH advisory plaque. The 65 is regulatory; the 40 is advisory. Taking the curve at 60 can still support a citation under the basic speed law if that speed is unsafe for the conditions, even though you are below 65. Slow before the curve, not in it.
Traps
Treating an advisory speed as the legal limit, or the posted limit as a target. Rolling stops where the line is not visible. Turning right on red where a NO TURN ON RED sign is posted. Missing a prohibition that applies only to trucks or only during certain hours.