If you have a choice whether to use a controlled access roadway (or freeway, expressway, etc), or a city boulevard, you should choose the controlled access road, because your potential for a collision is less. A freeway has no intersections, and, with few exceptions, traffic is typically moving at similar speeds. This contributes to safer travel.
But what's the best lane to use on the freeway? I suggest that in most cases, the center lane is your safest bet. While you read my advice on this topic, put your thinking cap on. This particular rule is an exercise in logic and experience, and there aren't many statistics that bear on the topic. You may have a different point of view, but I want you to think about it -- just as you should every aspect of the driving task.
Some driving instructors advise drivers to always use the right lane. I don't usually agree, but I see their point. (And when I'm on my motorcycle, I often use this advice, because of other overriding concerns.) It's based on the idea that speeds are slower in the right lane. Therefore if there is a collision, the results will be less serious and result in fewer injuries. However, near on/off ramps, the right lane is used for preparing to enter and exit -- it is the closest equivalent to an intersection on the freeway. With vehicles constantly transitioning on and off, there is an increased potential for collisions -- even if usually they are minor ones. My goal is to avoid ALL collisions.
Other instructors suggest the left lane is safest, because there are fewer vehicles over there. But we call that lane the "high speed lane" or the "passing lane," right? If you have a collision there, it can have serious results because of the higher speeds. Second, in many states, it is not legal to drive in the left lane unless you are passing someone -- vehicles that are not passing are required to drive to the right. Is there any such thing as a "high speed lane?" Is the speed limit any different in the left lane? The answer to both questions is, "No." Is it legal to speed in order to pass someone? It is not, contrary to popular belief.
I believe the center lane or lanes are the safest. One of your goals should be to avoid getting "boxed in." Constantly adjust your speed as necessary to maintain a safety cushion all around your vehicle. Don't let others drive in your blind spots, and don't drive in theirs. In the center lanes, you will find it is easier to ensure you have a "way out" when you need it -- because you'll have two ways to go. If you work to maintain your space, then the only vehicles to worry about are the ones you are passing, or who are passing you. With a lane on each side, you have increased odds of a clear path if you suddenly need one.
In the center lanes, you avoid the vehicle conflicts that occur in the right lane, and you are out of the way of the speeders and tailgaters common to the left lane. Anyone coming up behind can get around, left or right, if they want. All things considered, the center lane is where I want to be.
Keep the shiny side up!