It is quite worrying when you look at the percentage of drivers who do not realise what is illegal http://www.rac.co.uk/business/business-services-blog/legal-or-illegal
Interesting, thanks. The 18% on the smoking with children doesn't surprise me given the number I still see. I have to fight my vigilante urges otherwise I'd never actually get to work!
Driving with a partially cracked windscreen is only illegal if it's over a certain size and in certain places! Part of the mot testing rules!