Question While in a motor vehicle on a highway, it is: Answers Illegal to either drink from or possess open containers of alcohol. Legal to drink alcohol if you're not driving. Legal to drink alcohol if you're driving but not drunk. Explanation It is illegal to operate a motor vehicle while under the influence of alcohol. Neither drivers nor passengers may possess an open container of alcohol in a motor vehicle while it is in operation. This questions appears in the following tests: Wisconsin Motorcycle Practice Test 1 Wisconsin Motorcycle Practice Test 3