A car is necessary for getting around greater San Diego on the sprawling freeway system and for visiting the North County beaches, mountains, and desert. Driving around San Diego County is pretty simple: most major attractions are within a few miles of the Pacific Ocean. Interstate 5, which stretches north–south from Oregon to the Mexican border, bisects San Diego. Interstate 8 provides access from Yuma, Arizona, and points east. Drivers coming from the Los Angeles area, Nevada, and the mountain regions beyond can reach San Diego on I–15. During rush hours there are jams on I–5 and on I–15 between I–805 and Escondido.
There are a few border inspection stations along major highways in San Diego County, the largest just north of Oceanside on I–5 near San Clemente. Travel with your driver's license, and passport if you're an international traveler.
Gas is widely available in San Diego County, except in rural areas. Outlets are generally open 24 hours and accept major credit cards that can be processed at the pump. Full service is not available, but you will usually find window-washing tools next to a pump; water and air are available somewhere on the property. All fuel in California is unleaded and sold at three price levels. Pricing is per gallon pumped and varies widely by season, location, and oil company provider. In San Diego gas tends to cost about 15% more than it does in many other California cities.
Meters downtown usually cost $1 to $2.50 an hour; enforcement is 10–8 every day but Sunday. If you are headed to Horton Plaza, the mall validates for one hour with no purchase required. Be extra careful around rush hour, when certain on-street parking areas become tow-away zones. Violations in congested areas can cost you $45 or more. In the evening and during events downtown, parking spaces are hard to find. Most downtown hotels offer valet parking service. The Convention Center has nearly 2,000 spaces that go for $15 to $35 for event parking. On game day at PETCO Park, expect to pay $10 to $35 for a parking space a short walk from the stadium. Other downtown lots cost $10–$45 per day.
Balboa Park and Mission Bay have huge free parking lots, and it's rare not to find a space, though it may seem as if you've parked miles from your destination. Old Town has large lots surrounding the transit center, but parking spaces are still hard to find. Parking is more of a problem in La Jolla and Coronado, where you generally need to rely on hard-to-find metered street spots or expensive by-the-hour parking lots.
Highways are in good condition in the San Diego area. From 6 to 8:30 am and 3:30 to 6 pm, traffic is particularly heavy on I–5, I–8, I–805, and I–15. Before venturing into the mountains, check on road conditions; mountain driving can be dangerous. Check Caltrans or listen to radio traffic reports for information on the length of border waits from Mexico. For roadside assistance, dial 511 from a mobile phone.
In California you must be 21 to rent a car, and rates may be higher if you're under 25. Some agencies will not rent to those under 25; check when you book. Children up to age eight or under 4’9” in height must be placed in safety or booster seats. For non–U.S. residents an international license is recommended but not required.
Rates fluctuate with seasons and demand, but generally begin at $39 a day and $250 a week for an economy car with air-conditioning, automatic transmission, and unlimited mileage. This doesn't include an 8.75% tax.