In message <LBC*
p2...@news.chiark.greenend.org.uk>, at 23:09:35 on Mon,
11 Oct 2021, Espen Koht <
eh...@cam.ac.uk> remarked:
They aren't legal in the UK (on public roads) apart from a very few
examples which required special legislation (such as the Blackwall
Tunnel in central London).
An alternative is a height sensor that triggers a warning sign.
eg as installed at Ely! Either side, halfway to the bridge in this view:
http://www.perry.co.uk/images/signage-March-2019b.jpg
The permanently closed level crossing is on the right, but there's a
boatyard there too (you can just see the Hoseasons sgn).
A major part of the problem has to be vans ignoring the "Overheight
vehicles turn round" signage, even when activated, on the presumption
that like the traffic lights (and level crossing wig-wags forlornly
blinking years after the crossing was fenced off) they are generic,
rather than applying SPECIFICALLY TO THEM.
>(as would lowering the road one assumes?)
I'm becoming more and more convinced that this was a missed opportunity
when they fairly recently rebuilt the underpass. And not by feet, only
an inch would probably do.
The vehicles which hit the bridge are almost never "far too tall". As
for example when a double decker gets the top ripped off, or as happened
to another local bridge last year, a skip lorry comes to grief.[1]
The Ely underpass is spot on the height of an Ocado delivery van (one
got wedged under a couple of years ago, deflate the tyres to release
it), and about a centimetre lower than a very common type of Mercedes/VW
luton van (eg this weekend). Or exactly the height of this Ford:
http://www.perry.co.uk/images/September-22-2018.jpg
If someone had a bridge that was one centimetre lower than a regular
Land Rover Discovery or Range Rover, there's be an outcry - rather than
heckling about drivers not knowing how tall their vehicles are.
[1] Here's one that almost qualifies, a small van on a flatbed. While
the flatbed cab is a known height (one presumes, but it's often
difficult to find) if you put too big a load on the back, that might
not have been custom-measured before they set off.
http://www.perry.co.uk/images/16th-October-2019.jpg
--
Roland Perry