The 4:40 PM Left Turn on a One-Way Street
At 4:40 p.m. on a Tuesday you are northbound on a three-lane one-way street in downtown Baltimore, driving a 26,000-pound box truck in the right lane. You need to reach a loading dock two blocks west, which requires a left turn at the next intersection. On the mast arm you see a symbol sign showing a black left-turn arrow with a red slash, and directly below it a white plate reading "4 PM–6 PM MON–FRI." The cross street is marked "ONE WAY" pointing west, and the signal head facing you displays a green left-turn arrow. A "No Trucks" symbol sign with an "OVER 3 TONS" plate is mounted on the cross street, facing traffic coming from the other direction. Traffic is heavy, a cyclist is in the bike lane to your right, and your dispatcher is calling about the 5:00 window.
1. The left-turn arrow is green at 4:40 p.m. May you make the turn? Explain how you resolve the conflict between the signal and the sign.
Read the worked answer
No. A green arrow authorizes the movement; it does not override a regulatory sign that prohibits it. The sign-plus-plaque combination is a regulatory restriction with a time condition, and 4:40 p.m. on a Tuesday falls inside 4–6 PM Monday–Friday. The correct reading is: the signal says the movement is allowed when not otherwise prohibited, and the sign says it is prohibited right now. Two common traps: (1) treating the green arrow as permission that outranks the sign - it does not; (2) reading the "OVER 3 TONS" sign as applying to you - it faces opposing traffic, so it governs the other direction, not your turn (though your 26,000-pound truck would exceed 3 tons if it did apply). Practical move: continue north, take the next legal left, and call dispatch with a revised ETA rather than forcing the turn or stopping in the intersection.
2. Suppose it is now 6:20 p.m., the same left turn is needed, and the signal displays a flashing yellow left-turn arrow. What changes, and what must you yield to?
Read the worked answer
The time restriction has expired, so the prohibition no longer applies, and a flashing yellow arrow permits the turn only after yielding. You must yield to oncoming through traffic, to pedestrians in the crosswalk you are entering, and to any cyclist continuing straight - the bike lane on your right matters here because a cyclist going straight has the right of way over your turning path. A flashing yellow arrow is a permissive movement, not a protected one; do not assume oncoming traffic will stop. Because you are in a 26,000-pound truck, judge the gap generously: your acceleration is slow and a misjudged gap is not recoverable. Also re-check the weight sign's orientation before assuming it restricts you - it still faces the opposing direction. If oncoming volume is heavy, wait for a protected green arrow rather than creeping into the intersection.
3. At 4:45 p.m. a uniformed police officer standing in the intersection waves your lane forward and left, against the sign. What do you do?
Read the worked answer
Obey the officer. A police officer directing traffic takes precedence over signs, signals, and pavement markings; the sign's time restriction is suspended for as long as the officer is controlling the movement. Proceed slowly and deliberately, make eye contact, and confirm the gesture is aimed at your lane rather than the lane beside you - hand signals can be ambiguous in heavy traffic, and a 26,000-pound truck committing to the wrong interpretation is dangerous. Watch for pedestrians and the cyclist even though the officer has cleared you, because the officer's authority does not physically stop other road users. If the gesture remains unclear, stop and ask rather than guess. Once the officer leaves, the sign's restriction resumes; do not treat the officer's wave as a permanent exemption or as permission to repeat the turn on a later trip.