Rush Hour is the first expansion pack for SimCity 4.
This expasion allows you to take complete control of your city by allowing you to jump directly into the action. You can take control of a speedboat and chase criminals through your canals, you can take your Sims on a tourist ride by hopping into the engineer's booth of a train, you can track down criminals in a police car, being sure to avoid traffic, you can call in the heavy artillery and take control of your army's tank, or you can please the populace by taking control of a single engine plane and and impress everyone with skywriting.
