It's just trying to prove that humans simply can't multi-task and we focus on what we think is important. I managed a 100% ped count, but missed 8 questions because to me driving a car is more important than a cell phone. Maybe it was because my ex-wife is british and I automatically tune out the yabbering. When she said, "are you paying attention to me?", it sent shivers down my spine!
Being a cyclist/motorcyclist, I found this test neat:
http://www.dothetest.co.uk/basketball.html
At least they are trying to educated the masses about responsibility on the road. We just make stupid, uneducated rules and don't enforce them.