Traffic Signals and Signalized Intersections
Traffic signals assign right of way by phase, and the exam tests what each color and arrow requires, when turns on red are allowed, and how flashing modes differ from steady ones.
Core rules
- Steady red: stop at the stop line, crosswalk, or before the intersection; wait.
- Right turn on red is permitted in Pennsylvania after a complete stop and yielding to pedestrians and traffic, unless a sign prohibits it.
- Pennsylvania also permits a left turn on red from a one-way street onto another one-way street, after stopping and yielding, unless prohibited.
- Steady yellow warns that the light is changing; stop if you can do so safely, not accelerate.
- Green arrow: protected movement in the arrow direction; circular green: proceed when clear, yielding to pedestrians and oncoming traffic when turning.
- Flashing red: stop, then proceed when safe. Flashing yellow: proceed with caution.
Worked example
You face a steady red with a NO TURN ON RED sign. The general right-on-red rule does not apply because the sign is a specific prohibition. You must stop and wait for a green indication, even if traffic is clear. If the sign were absent, you could turn right only after a full stop, yielding to pedestrians in the crosswalk and to approaching traffic.
Traps
Right on red is not automatic; it requires a stop and a yield, and it is banned where posted. Left on red is limited to one-way to one-way and is not a general permission. A green arrow protects you from conflicting traffic, but a circular green does not. Do not enter an intersection on yellow if you cannot clear it.