Pay attention to your speed when you are driving. Most, if not all, modern cars have cruise control where you can set your speed if you are having trouble following the speed limits.
5mph is nothing at many speed limits. 50, 60, 70, 80mph
Ideally cars would be equipped with speed limiters. Then the problem disappears. Until this happens, there are many other solutions like you only start paying fines until you do over some limit (like 12 per year) of such minor infractions. Let's not take the focus from the main point: there is currently huge problem with reckless drivers causing death of tens of thousands of people per year (in US alone).