Everyday Metastability: Traffic Light Problem
• Traffic light: GREEN, ORANGE, RED sequence
• Sufficiently long ORANGE, GREEN periods
IS IT POSSIBLE TO RELIABLY AVOID
RUNNING A RED LIGHT ...
1. Under ANY circumstances
2. Without blocking intersection
3. Assuming you don’t slow down
when the light is continuously GREEN
PLAUSIBLE STRATEGIES:
A. Move at 55. At calculated distance D from light, sample color (using an unbounded-time arbiter). GO ONLY WHEN stable GREEN.
B. GO on GREEN; STOP otherwise.
C. Stop 1 foot before light. On GREEN, gun it.