it's a fair point.. but i reckon the safe speed limit would a lot less than 20mph.
and yes, it is going off topic.
IMO... all drivers should have their licences suspended for mobile phone use, regardless of whether they drive for a living, drive to get to work or just drive for leisure..
If the 5 or 10mph suggestion was not facetious, why follow it with the quilted bumper thing?
And I quite agree about mobile phone use.