Cars can be rented there, but unless you are planning to go out of town, parking in the downtown will be expensive, and traffic is quite congested.
Airport shuttles cost less and run frequently.
Taxi fares can be a little unpredictable, and you should be sure that you have agreed on the fare before you get in the cab. Shuttle service is via Grayline Airporter which leaves from the United baggage claim area every 20 minutes. By calling ATC , you will receive 10-15 percent off United Airlines and Delta tickets purchased more than 60 days prior to your travel dates. For tickets purchased less than 60 days prior to the convention, the discounts will be 5-10 percent . ATC is available 6am-6pm PST Monday through Friday.