How horrible is Phoenix traffic?

Travel Info
Haven't been there but will be going soon. Trying to decide if it would be smarter to get cabs or rent a car. I'm used to Dallas-Fort Worth traffic but I think Phoenix is a little bigger.

Travel Tips

Having lived in Chicago, and visited the 10 largest cities in the US, I will tell you Phoenix is not bad. We do have a good highway system, but the thing that impresses me is the surface streets. Almost all throughfares are 4 lanes wide, sometimes 6 lanes wide. The signals are pretty well timed, and left turn signals at most intersections. Two things to be aware of with streets. Phoenix left turn signals will only active if there are 3 or more cars waiting. Scottsdale's left turn signals are "lagging"--meaning the come on AFTER the main green. My advice, rent a car. However, Phoenix Airport has one of the country's HIGHEST rental car tax. If you can rent it "off airport" you will save some money.
Others

Traffic is not bad but the drivers are some of the worst you will ever see
The traffic was bad when I drove through 12/05 but the SMOG was unreal. And I lived in LA in the 60's and know smog. Couldn't get out of there fast enough.
Rent a car- cab fare will cost you a small fortune.

Like any major city, traffic is bad in the morning when everyone is going to work and the evenings when everyone is going home. Otherwise, its not too bad. Phoenix is laid out like a grid, with central avenue (runs north/south) as the dividing line. Everything running west of Central is an "avenue" and everything running east of Central is a "street". And they're all numbers-7th Street, 59th Avenue.
Any street names like Glendale, Bell, Thomas all run east/west. There are tons of freeways here to get around. And plenty of alternative routes if needed. The valley is really spread out, but really easy to figure out where you are. Good luck.
Definitely rent a car; just avoid rush hour. Traffic is not very bad at all outside of those times. Phoenix is also one of the easiest cities to navigate.
Rent a car, my experience with cabs in Phoenix is they are really expensive and totally unreliable. Right now, traffic is not so bad even during the typical rush hours, but of course it depends on the area of town as well. Traffic is horrible all the time all over when the snowbirds are here but the heat has chased them out now. The freeways and streets here are grid pattern so pretty easy to figure out but everything is far apart. Get a good road map and look at it before you come. Phoenix drivers are aggressive but if you stay to the right you'll be okay. The left lane is the fast lane and going 55 there will get you run off the road, even if that is the speed limit.
I would rent a car. Phoenix is very spread out. It's like one giant grid and cabs will drain your pockets. I don't really compare it to many other cities, esp. traffic wise. The traffic, in my opinion is not that bad. It can get bad on some parts of the 101, I-17, I-10, the 202 and a couple of other spots, but not that bad altogehter. Unless you will only be in one area, then maybe would be okay. ie: downtown phx or old town scottsdale.