A yellow light means you should speed up before the light turns red.

A yellow light indicates that the traffic signal is about to change to red, and it serves as a warning to drivers that they should prepare to stop. The purpose of the yellow light is to allow enough time for vehicles already in the intersection to clear it safely, while also giving those approaching the intersection a signal to stop if they can do so safely. Accelerating at this time can lead to running a red light, which is illegal and dangerous, potentially resulting in accidents. The appropriate action when encountering a yellow light is to slow down and prepare to stop rather than speeding up.