@ANef_is_Enuf : I understand exactly where you’re coming from. I have generalized anxiety disorder. I had a phobia of parking lots, and they still occasionally give me anxiety to the degree I can’t enter them.
Here’s the strategy I use that helps. First, as @john65pennington mentioned, leave the radio off. I choose not to distract myself in that way. Next, I chose a specific lane in the parking lot or, in some cases, area where I always go to park. If I can’t park there, I don’t go shopping that day.
The reason I’m bringing this up is because it works. Perhaps it would help you if you could pick a lane of the highway to always drive in. If you have to drive on a four-lane highway or street, then stick to the outside lane maybe, until you absolutely have to be in another lane. This might give your mind the kind of reassurance I’m talking about.
You’ve been given some excellent suggestions about taking practice drives. If you have the time, then do it.
I’ve saved the best for last. In order to help me focus clearly on what I’m trying to do, I talk to myself about the specific step of the task I’m trying to accomplish. I’ve used this for driving when I was also stressed out about something and needed to focus on the task at hand, getting from point A to point B.
I would say things to myself like “My hands are on the steering wheel. I’m pressing my foot down slightly on the accelerator. I’m lifting my foot off the accelerator. I’m turning on the turn signal. I’m turning the car. I see the red light ahead. I’m slowing down and stopping the car. Now I’m starting to go again.”
The point is that I talk to myself out loud about every little thing I’m doing. It may sound crazy, but it works for me. I use it for all types of activities, and it gets me through them with as little anxiety as possible.