Daytime xx mph
Nighttime xx kmh
Rain/Fog also require different limits, as it is the limits are too high for most roads anyway,we need to rid ourselves of the NSL and start again, country/minor roads should be 40mph tops, there's simply no need for them to have a higher limit. Residential roads/built up areas should be 20mph.
The vast majority of motorists cannot abide by them nor adjust their speed so that others around them and themselves are safe/not in fear of harm so
We can only do this by physically restricting the machines and by addressing the limits themselves (something governments/local authorities are loathe to do), humans are just really dog-do at making these judgements. We have the tech to be able to have this in all new motors and older vehicles should be retrofitted at the expense to the vehicle owner. If that prices some people off the roads that's a win win situation.
One can only dream as we can't even get gov to make small changes to address the killing and maiming spree never mind the injustice against cyclists by police and so called justice system!