It depends on the style of burqa. If you're asking about the style that we have seen associated with Afghan women, the field of vision is incredibly limited. A friend's husband was deployed to Afghanistan last year, and he brought a burqa home for her. It is very difficult to see out of. I can't imagine having the necessary range of motion and vision in order to safely drive.
Other burqas, though, have no impact on vision. It all depends on how fitted the headpiece is and whether there is a scarf or screen in front of the eyes.
I know there is great debate in Europe and the U.K. about whether to allow people to wear burqa, etc. It will be interesting to see where the debate goes.
