whislt bein held captive at sainsburys stoke i got chattin to another driver we got to talkin about gettin stuck at low bridges etc i told him how i ended up on a rd with 2 bridges the same hight as my trailer n was forced to blindside into a tiny side st to get out of the situation anyway this fellow driver went on to say how every bridge that is marked up with a height is actually 2 or 3 inch higher than stated on the sign an that if he meets a bridge the same height as him he will always go through it is this true or is the bloke as i suspect 1 either full of it or 2 a fool n eventually come unstook
there was a guy at our place who crept under a 12’ 8 bridge even though his truck was 12’ 9!
i would assume there must be some safety paramiters
Ive taken a 14’9 trailer underneath a 14’6 bridge in princes risborough near the M40 but wouldn’t do it again or make a habit out of it.
Our double deckers also go under a bridge in greenford on the way to Palletways hub thats marked up at 15’6 and our deckers our 16ft but u don’t even have to drop the air as there is still about 2 inches clearance.
The highways agency by law has to mark up a bridge 3 inches lower than it actually is. I always take a truck underneath a bridge that is marked up the same height as the trailer but I wouldn’t bounce through it put it that way.
the way i always c it is that if u ■■■■ it an hit the bridge first thing they look at is your height n then its u in ■■■■ st for doin it the reason i turned around that time was due to the fact the bridge as over the top of a brew n didn fancy my chances
FarnboroughBoy11:
The highways agency by law has to mark up a bridge 3 inches lower than it actually is.
Maybe that’s a resurfacing margin 
There is USUALLY a couple of inches leeway - but don’t forget that you commit an offence by going under a bridge that has a height marked less than your vehicle height - even if you clear it…
I’d only go under if its gonna be an arse hole to turn around but would be bloody carefull.
Triangle warning signs are advisory and can state anything up to 3" lower than the bridge but they don’t have to be by law. If it’s a circular sign then it’s against the law to go under it if your over the height stated.
At my old place we used to do a delivery off upper Clapton road with a 16’ trailer. The designated route in was off the 406 on to the 107 and under a bridge marked up 16’ in a triangular sign. We could fit under it, just. One day my mate rang me saying he’d heard a thud as he went under it nothing to bad but was certain he’d clipped it. I met up with him later that day and the trailer he had on, had hit a tree (or something) a while before and was creased up may be 1" may be not even that. We decided that the raised bit if the trailer had clipped the bridge. So just telling you that tale to say that not all bridges are marked up 3" lower than they are 
Loads of trucks have gotten stuck under Southport pier over the years (heading from S to N)
Drivers can find their trailer fits nicely under the pier with inches to spare, trouble is the road then rises quite sharply which goes unnoticed with the mini roundabout road layout, and the trailer ends up wedged solid around the halfway mark.
The Sarge:
There is USUALLY a couple of inches leeway - but don’t forget that you commit an offence by going under a bridge that has a height marked less than your vehicle height - even if you clear it…
I didnt know that.
Why are some bridge height markers triangle and some circle?? Always wondered as circles are ment to be orders and triangles warnings.
I have always been told that the marked height is the maximum height wagon that can safely pass under it.
cliffton 27:
whislt bein held captive at sainsburys stoke i got chattin to another driver we got to talkin about gettin stuck at low bridges etc i told him how i ended up on a rd with 2 bridges the same hight as my trailer n was forced to blindside into a tiny side st to get out of the situation anyway this fellow driver went on to say how every bridge that is marked up with a height is actually 2 or 3 inch higher than stated on the sign an that if he meets a bridge the same height as him he will always go through it is this true or is the bloke as i suspect 1 either full of it or 2 a fool n eventually come unstook
The round signs gives the maximum height of a vehicle which can proceed beyond the sign and will be less than the height of the bridge. Pass that sign with a vehicle higher than the height marked on the sign and you commit an offence similar to going through a red light.
The triangle signs show the maximum headroom under the bridge.
If either of them show the same height as the vehicle you are driving you can proceed.
Of course it is all dependent on you knowing the actual height of your vehicle and not relying on an indicator in the cab or some random numbers on the trailer headboard. That’s where one of these can save you many miles of detour.
jc69817:
I have always been told that the marked height is the maximum height wagon that can safely pass under it.
Me too, I run at 14’ 6" and go under 14’ 6" marked bridges all the time without worrying, maybe I should start worrying?
theres a bridge in walsall marked 14ft and I go under it most nights with a 16ft DD, and theres still about a foot spare
We had a guy working for us who shot under a 14’6" with a 15’6" trailer in Luton but unfortunately he didn’t get all the way under it, his illegally carried passenger (Girlfriend) did though, cam flying through the windscreen at about 60 kph 
waynedl:
jc69817:
I have always been told that the marked height is the maximum height wagon that can safely pass under it.
Me too, I run at 14’ 6" and go under 14’ 6" marked bridges all the time without worrying, maybe I should start worrying?
Why should you? Sign shows maximum height of a vehicle which can pass under the bridge and you are the same height as that so no problem.
When I was new at our place ‘a good’ driver crunched his 15’8" trailer into the 15’6" bridge on the A20 near Lenham.
I asked him why he went that way and he said it was because that’s what he always did. Turns out he pressed the wrong button on his air suspension (because he was on the phone) and lifted the trailer high enough to write it off.
He didn’t get prosecuted or even fired but he did have to tow the wrecked trailer all the way to Preston.
He left within the month.
W
AlexWignall:
When I was new at our place ‘a good’ driver crunched his 15’8" trailer into the 15’6" bridge on the A20 near Lenham.I asked him why he went that way and he said it was because that’s what he always did. Turns out he pressed the wrong button on his air suspension (because he was on the phone) and lifted the trailer high enough to write it off.
He didn’t get prosecuted or even fired but he did have to tow the wrecked trailer all the way to Preston.
He left within the month.
W
I’d have prosecuted and sacked the muppet for being on the phone AND playing with the air suspension whilst the vehicle’s moving. MUPPET!!
I have been told that bridge heights are measured from the top of the pavement if there is one, and that there is therefore more clearance under a bridge if it has a pavement running beneath it. I do not know if this is true, but from observation it would appear that it is.