625 ILCS 55/5

(a) The taxi driver's picture, the taxi driver's license or registration number, and the taxicab medallion number or an exterior identification number must be posted in a visible location in each cab. (b) There must be posted in a visible location in each taxicab a telephone number for a passenger to call if the taxi driver is operating the taxicab in a reckless manner. (c) If a taxi driver collides with a pedestrian while operating a taxicab, resulting in bodily injury, then any responding law enforcement officers must test the taxi driver for drug and alcohol use.