on a politics note, surely increasing the speed limit has its benefits?
Only if the speed limit was not set based on safety concerns, but others, such as fuel economy. I admit to being a slow driver, tho except on rural interstates, my slowness is limited to driving only the speed limit. (Too many drivers treat speed limits as if they were minimums, a la
Fahrenheit 451, instead of maximums.) My default top speed for rural interstates unless I need to go faster to meet my schedule is 100 km/h. (Going a little faster than 60 mph helps keep me from ending up in clump of drivers doing 60 which is a favored speed for my fellow slow drivers, and 100 km/h is helpfully marked on the speedometer so it's easy to follow.
Going 100 km/h has the dual advantages of improved fuel economy and giving me a built in safety factor for my schedule as I can easily speed up if I get delayed.