I'm having an issue where the brake and throttle are stuck with half input. I have uninstalled and reinstalled the game but I keep having the same issue. 

Maybe you have a controller attached like a steering wheel? Some controllers use 0.5 as the "idle" position for some axes. If that's the case, you can either unplug the controller or edit the axis bindings in config.ini to something that's not an axis on your controller (set axes to -1 for example).