We have a great set of units for measuring and communicating… height, weight, speed, money, light, time and so on. An very cleverly they have become very scalable over time. As soon as we have 60 minutes we start counting hours, when we get to 7 days, we start counting weeks, at 100 pence we start counting pounds and so on.
However these are not always applied as sensibly as they might. That just creates unnecessary barriers to understanding.
A publically odd one is that associated with roadworks….. “Works starts here from 20 January for 15 weeks”. This seems part information part quiz. To effectively triangulate this – and help us more easily understand the impact on us - we also need the end date. Deduceable but not explicit. So here counting weeks when months might be more logical. Maybe it’s something about making the end date less explicit to more easily cope with a possible over-run.
This information is presented in a way that makes you have to do some unnecessary mental maths while driving. It might go something like this... “20 weeks…that means 20 divided by 4 weeks and a bit per month on average means about 3 and half months. And 30 days hath November etc… which means they should be done by…………. 4th April”. That’s concentration that’s not being applied to driving, and especially in an area which needs extra care as there are roadworks. This is one way to improve national levels of numeracy, but probably not the safest.
So I propose a standard sign, with start, duration and finish. No distracting mental maths here.