# COLREGS handling notes (CEDAR)

Three give-way geometries we actually implement (Kuwata et al. style):

- head-on (Rule 14): both alter to starboard. symmetric. easy case.
- crossing (Rule 15): vessel with other on its starboard gives way. we pass astern.
- overtaking (Rule 13): overtaker keeps clear, either side, but prefer starboard.

Velocity-obstacle layer sits UNDER the rule layer:
1. compute VO for each contact (collision cone in velocity space)
2. rule layer biases the chosen velocity to the COLREGS-compliant side of the cone
3. RL policy only kicks in for dense/ambiguous traffic (>4 contacts in gate)

open q: stand-on vessel behavior (Rule 17) — when do we assert? right now we
hold course too long. Kuwata punts on this too iirc. check.