It seems like you are getting a synchronization problem. Does it only happen on high population areas? If yes, then avoid driving in those places.
I am not sure if clearing the DNS cache, nor the winsock catalog would help, but I would certainly give it a shot. You need to open the command prompt on your computer with administrator's privilege, and type "ipconfig /flushdns" without the quotes and press enter. When it's done, then type "netsh winsock reset all" and press enter. After it's complete, it will ask you to restart computer, then do so.
Another thing I would try if I was you, I would uninstall TruckersMP from your programs and features. Then delete TruckersMP folder in Documents and make sure it is also deleted from Program Files. Run CCleaner, click Registry tab on left, then scan for issues. It will prompt you to ask if you want to backup registry keys, you can if you want, but you don't have to. It never caused problems to me, but who knows. After scan is done, you can click fix all, then install TruckersMP.
Please give us any updates on the issue, if it still persists, or if you have found a workaround.