kidney function elevated. My doctor called and said that my kidney function was elevated just a little.
Caution.. It means that traffic approaching the yellow light has the Right-of-Way to proceed through the intersection, but a significant volume of traffic is, or may be, approaching from the cross street(s). The driver is thus warned to be wary of vehicles that may be entering or crossing the roadway.
Some traffic lights are timed to reflect the common flow of traffic, but others are designed to keep heavy traffic moving with green lights until they detect vehicles that arrive at a cross street and change accordingly.