Navigation lights must be displayed between sunset and sunrise for recreational boats. International and Inland Navigation Rules are nearly identical. Sailboats under power must display black "steaming cone" with downward apex
Traffic rules vary by location and should be studied before driving. Stop signs require complete stop, even if slowing down. Speed limits are indicated by white signs with black numbers. Yield signs indicate caution and check both ways. Black arrows show directional restrictions
NUC vessels display two red lights and two balls in vertical line. RAM vessels show three lights: two red, one white, three balls, one diamond. RAM vessels add masthead, sidelights, and sternlight when making way. RAM vessels at anchor use lights from Rule 30
Part C of COLREGS covers navigation lights requirements. Rules apply to various vessel types including power-driven, sailing, fishing, and seaplanes. Rules specify visibility requirements for different vessel lengths
Smart traffic lights combine traditional lights with sensors and AI for intelligent traffic control. Carnegie Mellon University developed system for Pittsburgh to reduce emissions. System uses fiber optic receivers to monitor vehicle numbers in real time
Traffic lights control traffic flow at intersections and crossings. Standard signals use red, amber, and green in specific order. First traffic lights installed in London Parliament Square in 1868