See this often. Bridge height, 16’0” 4.8m. 16ft is 4.88m, not 4.8.
I often pull a 15’10 trailer which is 4.83m.
So if I go under a bridge that says 16ft and 4.8m then if I go off imperial units I’m within the clearance, if I go off metric I’m too high. So if I smash into a 16ft bridge in a 15ft 10 trailer that is also a 4.8m bridge that should be 4.88 and I’m in a 4.83m trailer. Is that then my fault?
They need to sort the signs out.
Lift your suspension all the way up and steam into it. That will teach them.
We need more bridge hits Stobarts are not meeting their quota of bridge strikes.
Rowley010:
See this often. Bridge height, 16’0” 4.8m. 16ft is 4.88m, not 4.8.I often pull a 15’10 trailer which is 4.83m.
So if I go under a bridge that says 16ft and 4.8m then if I go off imperial units I’m within the clearance, if I go off metric I’m too high. So if I smash into a 16ft bridge in a 15ft 10 trailer that is also a 4.8m bridge that should be 4.88 and I’m in a 4.83m trailer. Is that then my fault?
They need to sort the signs out.
Different calculation methods used to arrive at the marked figure using metric vs imperial units. It is all explained in the official Road Signs Manual. The discrepancy comes from the way the measurements are rounded up to ensure a safe clearance margin.
Sent from my SM-G920F using Tapatalk
Roymondo:
Rowley010:
See this often. Bridge height, 16’0” 4.8m. 16ft is 4.88m, not 4.8.I often pull a 15’10 trailer which is 4.83m.
So if I go under a bridge that says 16ft and 4.8m then if I go off imperial units I’m within the clearance, if I go off metric I’m too high. So if I smash into a 16ft bridge in a 15ft 10 trailer that is also a 4.8m bridge that should be 4.88 and I’m in a 4.83m trailer. Is that then my fault?
They need to sort the signs out.
Different calculation methods used to arrive at the marked figure using metric vs imperial units. It is all explained in the official Road Signs Manual. The discrepancy comes from the way the measurements are rounded up to ensure a safe clearance margin.
Sent from my SM-G920F using Tapatalk
So if I strike a 16ft or 4.8m bridge with a 15’10 or 4.83m trailer am I in the wrong? Or is my company making a claim to the people that mark it all up?
I appreciate there different calculations but the difference between 4.8 and 4.88 which is actually is is 8cm, which is significant. It’s not like it’s a few millimetres different.
Rowley010:
Roymondo:
Rowley010:
See this often. Bridge height, 16’0” 4.8m. 16ft is 4.88m, not 4.8.I often pull a 15’10 trailer which is 4.83m.
So if I go under a bridge that says 16ft and 4.8m then if I go off imperial units I’m within the clearance, if I go off metric I’m too high. So if I smash into a 16ft bridge in a 15ft 10 trailer that is also a 4.8m bridge that should be 4.88 and I’m in a 4.83m trailer. Is that then my fault?
They need to sort the signs out.
Different calculation methods used to arrive at the marked figure using metric vs imperial units. It is all explained in the official Road Signs Manual. The discrepancy comes from the way the measurements are rounded up to ensure a safe clearance margin.
Sent from my SM-G920F using Tapatalk
So if I strike a 16ft or 4.8m bridge with a 15’10 or 4.83m trailer am I in the wrong? Or is my company making a claim to the people that mark it all up?
It’s not going to happen - the measured clearance under that bridge must be at the very least 16’ 3". If the clearance was only 16’ 2" it would have to be signed as 15’ 9".
Also, a bridge marked as 4.8m could have been measured at anywhere between 16’ and 16’4"
Since both the above are true (marked as 16’ and 4.8m) the measured height must be between 16’ 3" and 16’ 4" (any lower and the imperial markings would have to be 15’ 9", any higher and the metric markings would be 4.9m)
adam277:
Lift your suspension all the way up and steam into it. That will teach them.
We need more bridge hits Stobarts are not meeting their quota of bridge strikes.
Well I’ve certainely done my bit over the last week
8cm is a touch over 3". (3.149" actually)
Would you really risk getting through with just that amount of clearance?
Or put another way. Would you drive through a gap with just 1.5" gap each side? (3" total)
If they round down the conversion, you will be safe for height (re-surfacing excluded…)
Or just make sure the number on the bridge is bigger than the one in your cab. Or you what you measured on the trailer.
If you’d like to discuss uncertainties of measurement, profiles and tolerances, then let me know.
Paul
Frequently work within those tolerances.
Occasionally tighter too, but I tend to do that somewhat slowly.
If a bridge has a circular prohibition sign of say 4.0m then I will happily go under knowing my trailer is under 4.0m. Only a tad under but it is. The UK and France have some tolerance built into the system.
Italy (from personal experience) mark bridges with their exact height. A 4.0m bridge there isn’t a 4.0m clearance, it is, or can be a bare 4.0m.
We need to do away with imperial measures for heights in this country. Everywhere else in Europe uses metres; only the USA and Canada use imperial, and we have no land border or vehicle ferry links with either so none of their trucks here. Petrol stations have canopy heights in metres; trailers typically have a height in metres on a 5th wheel height which is usually 1250mm. We wouldn’t have these discrepancies if we just used a modern measurement rather than an imperial throwback.
IndigoJo:
We need to do away with imperial measures for heights in this country. Everywhere else in Europe uses metres; only the USA and Canada use imperial, and we have no land border or vehicle ferry links with either so none of their trucks here. Petrol stations have canopy heights in metres; trailers typically have a height in metres on a 5th wheel height which is usually 1250mm. We wouldn’t have these discrepancies if we just used a modern measurement rather than an imperial throwback.
Sensible as that is, dont hold your breath. Its only been going on for the past 50 (?) years.
IndigoJo:
We need to do away with imperial measures for heights in this country. Everywhere else in Europe uses metres; only the USA and Canada use imperial, and we have no land border or vehicle ferry links with either so none of their trucks here. Petrol stations have canopy heights in metres; trailers typically have a height in metres on a 5th wheel height which is usually 1250mm. We wouldn’t have these discrepancies if we just used a modern measurement rather than an imperial throwback.
Your forgetting that in cab signs are in feet and inches.
Personally I hate metric, it means sod all to me. How many tall people say they are over 1.8288m rather than 6ft tall?
Sand Fisher:
IndigoJo:
We need to do away with imperial measures for heights in this country. Everywhere else in Europe uses metres; only the USA and Canada use imperial, and we have no land border or vehicle ferry links with either so none of their trucks here. Petrol stations have canopy heights in metres; trailers typically have a height in metres on a 5th wheel height which is usually 1250mm. We wouldn’t have these discrepancies if we just used a modern measurement rather than an imperial throwback.Your forgetting that in cab signs are in feet and inches.
Personally I hate metric, it means sod all to me. How many tall people say they are over 1.8288m rather than 6ft tall?
Measuring everything in metres makes as much sense as measuring everything in yards with the exception of landing an artillery shell in the right place.Which is also why aircraft heights are generally measured in feet above the ground so as not to wipe out the landing gear on landing.While going by similar logic bridge heights and people are measured in feet and inches and ground distances are measured in miles and fractions of a mile,not bleedin yards and therefore anything but a supposed ancient throwback. 
Carryfast:
Sand Fisher:
IndigoJo:
We need to do away with imperial measures for heights in this country. Everywhere else in Europe uses metres; only the USA and Canada use imperial, and we have no land border or vehicle ferry links with either so none of their trucks here. Petrol stations have canopy heights in metres; trailers typically have a height in metres on a 5th wheel height which is usually 1250mm. We wouldn’t have these discrepancies if we just used a modern measurement rather than an imperial throwback.Your forgetting that in cab signs are in feet and inches.
Personally I hate metric, it means sod all to me. How many tall people say they are over 1.8288m rather than 6ft tall?
Measuring everything in metres makes as much sense as measuring everything in yards with the exception of landing an artillery shell in the right place.Which is also why aircraft heights are generally measured in feet above the ground so as not to wipe out the landing gear on landing.While going by similar logic bridge heights and people are measured in feet and inches and ground distances are measured in miles and fractions of a mile,not bleedin yards and therefore anything but a supposed ancient throwback.
Aircraft mostly use feet for altitude because the Americans cling grimly to Imperial units, or rather a ■■■■■■■ son of Imperial and metric and it’s more important to have standardisation than to worry about which units to use. I seem to remember a lander crashing into Mars because the Americans read kilometres as miles.
I do agree that height signs should be shown in metric and the feet/inches conversion dropped.
Keep it to feet and inches thanks .
