Altho' I went to all my son's treatments, it was the nausea that encouraged him to turn the driving over to me. Having a nice square plastic dish pan in the car is very useful. If you lay a couple of paper towels in the bottom, clean-up is easier. You could put a smiley face sticker on the outside. And bring a bottle of water. At his last treatment, the hospital staff gave him a graduation present of a plastic dishpan and I always wondered why they hadn't done it sooner! I had been putting lots of towels in the car for the nausea. You might encourage the driver to take it easy over bumps and curves. You might not need any of this - I have heard of people not having any trouble at all but it doesn't hurt to be prepared for eventualities.