Want trip itinerary which avoids big city traffic
Try to travel highways before/after rush hour (7:30am-9:00am and 2:30pm-6pm). Phoenix has become quite large with lots of traffic! If possible, take 'secondary' main surface streets to get where you're going during high traffic hours, e.g., take Osborn not Thomas, take Missouri not Camelback, etc. Know alternate routes that avoid the I-10 or just use the 10 a bit to get to a less-busy surface street, especially during those rush times. Hope that helps!
Avoid traveling when people are commuting to and from work. Especially on the highways. Other than that Phoenix is very easy to get around because it's roads are setup on a grid system.
Mentioned in this answer:
as much as it sucks, theres no way to get into the city without hitting city traffic. Earlier times are better but either way theres some traffic