Conspicuity for the rear of a vehicle is provided by rear position lamps (also called taillamps or tail lamps, taillights, or tail lights). These are required to produce only red light and to be wired such that they are lit whenever the front position lamps are lit, including when the headlamps are on. Rear position lamps may be combined with the vehicle's stop lamps or separate from them. In combined-function installations, the lamps produce brighter red light for the stop lamp function and dimmer red light for the rear position lamp function. Regulations worldwide stipulate minimum intensity ratios between the bright (stop) and dim (rear position) modes, so that a vehicle displaying rear position lamps will not be mistakenly interpreted as showing stop lamps, and vice versa.