Are you renting a vehicle - if you are then factor in the amount of time it will take to catch the rental car shuttle and pick up your vehicle. This will likely add about half an hour to your travels. Traffic will likely be manageable but we have found that in any large metropolitan area traffic can pop up and bite you when you least expect it - all it takes is one accident and poof it's stop and go, or just stop! Google maps is great for letting you know where the red is you should avoid, I'd check that before leaving to be able to perhaps avoid certain routes.