Often the limit is way lower than the "safe" speed - e.g. the variable speed limits on motorways restricting you to 40mph on an empty road in perfect daytime co

Often the limit is way lower than the "safe" speed - e.g. the variable speed limits on motorways restricting you to 40mph on an empty road in perfect daytime conditions, or the 15mph limit for London - both only exist to manage traffic flow and/or dissuade people from driving. You're welcome to match other drivers - enjoy the speeding tickets you'll both get.