Pavement Markings and Signals
Pavement markings and signals carry the same authority as signs. Yellow lines separate traffic moving in opposite directions; white lines separate traffic moving the same direction or mark the edge of the roadway. A solid yellow line on your side means no passing; a broken yellow line means passing is permitted when safe. Two solid yellow lines prohibit passing in both directions. White dashes separate lanes of same-direction traffic; a solid white line marks the right edge, and a solid white line on the left of a lane means stay in that lane. Crosswalk lines, stop lines, and railroad markings round out the set.
Traffic signals: a steady red means stop; a steady green means proceed if the intersection is clear; a yellow light warns that red is coming, so stop if you can do so safely rather than accelerating. A flashing red is treated as a STOP sign; a flashing yellow means proceed with caution. A green arrow gives a protected turn in the direction of the arrow. A dark or failed signal at an intersection is treated as an all-way stop in many jurisdictions, so slow, stop, and proceed in turn.
Traps: confusing flashing red (stop, then go when clear) with flashing yellow (caution, no mandatory stop); treating a yellow light as a signal to speed up; passing on a solid yellow line; and ignoring edge lines. Worked example: you see a broken yellow line on your side and a solid yellow line on the opposing side. Passing is permitted for you when safe, but not for oncoming traffic.