Generally speaking there could be malicious data-reporting but this is what our Verification step is for. Am I right in assuming that a HMV map contains a user-specification for height and width. Is the overall mass included in these specs?
While the width is likely to remain fixed, height and mass would clearly change depending on load. A difficulty I can see is that if you drive outbound loaded, then wxh & m will be very important factors to recognise in the route designed in unit. If the return just happens to be in no-load conditions, as a driver, you might want to use a more direct route. This implies that the vehicle specifications have to be carefully chosen (and set) for laden or unladen states.
OK - the foregoing is merely some Sunday evening musing. This signposting is of absolute importance for us to be able to present a map accurate for HMV's. I would consider that this could be a Worldwide phenomenon/valid need and have sent a note in to highlight the 'lack of relevant data' spoken of here. It's not easily done via reports in MSR.
I guess one has to trust the Road Engineers responsible for signposting that permitted height is measured on the outside track of the tunnel and not the absolute top-to-bottom on the centre-line given many or most tunnels have a curved hanging wall 
Madtrucker - was wondering if you could be a little more specific in your comment. Is it in relation to the subject under discussion, if so would you be able to make some suggestions? It's hard to deal with a wide ranging comment.
