I'll check it out right now. Be back with the results.

Update:

I tried it in both directions. Sorry, but I didn't notice any wall, either visually, or invisible via Interstate 5 to Highway 101, in Single Mission.

Thanks for trying. I guess the problem is just isolated to my computer.

.... Or your graphics card. What do you have?

I have an Nvidia 7800. It is well over the minimum requirements. I found another "wall" on my way to Mojave from Oxnard. I think I figured it out though. I can not see some of the competing trucks and when I try to pass them, I run into a wall. I think that I run into a trailer instead of a wall. But that poses another problem, why can't my computer show other trucks? The computer is pretty old but it almost meets the recommended requirements and it is well over the minimum.

NVidia is program that supports your graphic card. What is your graphics card? With this game, almost won't work. You need the minimum spects, but I reccomend the suggested specs.

Please provide a picture of what you are talking about.

So then, USA Trucker, could my processor be the problem. That is the only component that does not fit the recommended specs.

Yes, it could very well be. I don't what your processor is. Can you tell us? The game specifies what you need, both minimal, and recommended. I would shoot for the higher/better recommendations. Today, upgrading a computer is not as expensive as it use to be. Heck, even buying the one I have with 8gb ram, G-force 9500 Video Card, Intel Core 2, Quad, 2.9 GHz cost less then $1,200!

Of course if you can't afford that, then upgrade what you need to get the game to run properly.

Writing about the problem of invisible wall ??????
If so, I read this issue with Russian colleagues.
I say try one ride (not the campaign) to run and pass the place where the invisible wall. If there is not, it's a problem loading wrong career line. The solution is to start a new campaign.
If the invisible wall and there in a contract free ride, then a problem with installing games. Advises that to reinstall the game! Really helps.
I heard many, many problems resolve when reinstal the game to resolve any problems.

If you re-install, then you need to de-activate the first installation, if I understand it correctly. This way you don't lose your 3 activation options. You are granted 10 de-activations. Don't confuse this with the 3 ACTIVATIONS!