Many people can drive right up until, although you might not feel like it. I remember Skittlebub drove maybe 45 min to and from my house and went into labour the next day, so it can be done!

My car seats sloped downwards and put pressure on some vein or something with #1 and I would almost pass out every time I was in that car from about 25 weeks onwards, so I didn't drive, just sat in the passenger seat with cushions. I didn't bother trying in late pregnancy with #2, mostly cos I was able to avoid it.

So barring any medical thing that makes you concerned, you should be able to drive for as long as you like!