The appellate court said the city has the authority to tax cars rented by city residents within 3 miles of the city's border based on a presumption that the vehicle would be used primarily in the city. The court said the taxable event is the use of the rental car in Chicago, and so the city has the power to tax it. The court also said a use tax by the city is justified, partly because the resident renting the vehicle might be using the city's roads and police protection.