Not sure wether to ask on this or the Euro forum 
Remember the illuminated yellow triangles on a blue square.
They used to be mounted on the top of the cab of (what i thought at the time) only Portugese motors but have seen a few pics from the late 60s/early 70s of them on other Euro motors .Did you have to have them to run into Portugal,also
what did the sign signify?
Hiya …i don,t know if i,am 100% correct but i narrowed it down to a vehical towing a trailer.
it seemed a good idea to me, you can see a van or car that will,nt get from the middle to outside lane
on a motorway, then you find he has a trailer. so when i,ve seen cars and vans with the triangle i
know he can,t go to the outside lane . hope this is helpful and correct
john
Hi im almost sure they were spanish and a sign of a long distance truck.
At least thats what a spanish driver told me about 1974 we loaded tomatoes in Alicante to london.
HH.
I remember seeing them throughout the 80`s,and also illuminated yellow crosses. Always on a Spanish truck but sometimes of a Portuguese.Usually there were more than one on the roof.
I thought that it had some sort of religious significance, something along the lines of a St Christopher and that the colour or shape varied depending on what part of Spain the vehicle was from!!
Would be interested to find out the real meaning.
3300John:
Hiya …i don,t know if i,am 100% correct but i narrowed it down to a vehical towing a trailer.
it seemed a good idea to me, you can see a van or car that will,nt get from the middle to outside lane
on a motorway, then you find he has a trailer. so when i,ve seen cars and vans with the triangle i
know he can,t go to the outside lane . hope this is helpful and correct
Hiya …my typing finger never said portugal
Hi Guys, you’ve nearly got it correct between you. It was in actual fact a Spanish law that was sometimes used by the Portuguese simply because they thought it a good law. All lorries had to sport a blue square on the top of the cab to denote that they were a commercial vehicle. If towing a trailer ,then they also had to show a yellow triangle on a seperate blue square( in other words both of the signs). Any car or van towing any type of trailer (including a caravan) had to show the yellow triangle on a blue backing to also show oncoming traffic that they were towing. None of these signs had to be illuminated but were much more effective if they were.
I hope this clarifies the reason behind the fact.
TIR Original:
Hi Guys, you’ve nearly got it correct between you. It was in actual fact a Spanish law that was sometimes used by the Portuguese simply because they thought it a good law. All lorries had to sport a blue square on the top of the cab to denote that they were a commercial vehicle. If towing a trailer ,then they also had to show a yellow triangle on a seperate blue square( in other words both of the signs). Any car or van towing any type of trailer (including a caravan) had to show the yellow triangle on a blue backing to also show oncoming traffic that they were towing. None of these signs had to be illuminated but were much more effective if they were.
I hope this clarifies the reason behind the fact.
Thats what I was told too!
So what was the 3 green lights for on the roof of Japanese trucks ? 
Trev_H:
So what was the 3 green lights for on the roof of Japanese trucks ?
Hiya …Trev-H …I think it also runs to the USA market the 5 yellow cab lights/5 red back lights denote
heavy trucks and not just for show… in Cyprus they put 2 extra sidelights just under the windscreen.
Sorry you had a rough xmas mate plenty of thoughts at this end… chin up.
John
Trev_H:
So what was the 3 green lights for on the roof of Japanese trucks ?
Go Go Go
Sorry Regards Keith
I drove an Isuzu artic one day in the 70’s a rare beast in this country at that time, the lights on the roof were linked to lights in the speedo when you got past 60mph all 3 lit up, must have been some crazy Japanese law. I also have a Japanese home market Honda bike, this has a speed warning light in the clock, first time it lit up I pulled up quick! Its the same colour as the oil warning light 
Dieseldogsix:
TIR Original:
Hi Guys, you’ve nearly got it correct between you. It was in actual fact a Spanish law that was sometimes used by the Portuguese simply because they thought it a good law. All lorries had to sport a blue square on the top of the cab to denote that they were a commercial vehicle. If towing a trailer ,then they also had to show a yellow triangle on a seperate blue square( in other words both of the signs). Any car or van towing any type of trailer (including a caravan) had to show the yellow triangle on a blue backing to also show oncoming traffic that they were towing. None of these signs had to be illuminated but were much more effective if they were.
I hope this clarifies the reason behind the fact.Thats what I was told too!
Same here mate, but there were several rumours doing the rounds at the time. 
I used to go to Spain quite regularly (but not Portugal) back in the early 80s, and the blue square / yellow triangle thing was in operation at that time.
dieseldave:
Dieseldogsix:
TIR Original:
Hi Guys, you’ve nearly got it correct between you. It was in actual fact a Spanish law that was sometimes used by the Portuguese simply because they thought it a good law. All lorries had to sport a blue square on the top of the cab to denote that they were a commercial vehicle. If towing a trailer ,then they also had to show a yellow triangle on a seperate blue square( in other words both of the signs). Any car or van towing any type of trailer (including a caravan) had to show the yellow triangle on a blue backing to also show oncoming traffic that they were towing. None of these signs had to be illuminated but were much more effective if they were.
I hope this clarifies the reason behind the fact.Thats what I was told too!
Same here mate, but there were several rumours doing the rounds at the time.
I used to go to Spain quite regularly (but not Portugal) back in the early 80s, and the blue square / yellow triangle thing was in operation at that time.
I was always told it was to distinguish international from national operators but trucknet teaches us something new everyday. But to have an obscure sign that is 5 inches square on a 50’ truck is like having a Phaeng sticker on a Danish motor 
Wheel Nut:
dieseldave:
Dieseldogsix:
TIR Original:
Hi Guys, you’ve nearly got it correct between you. It was in actual fact a Spanish law that was sometimes used by the Portuguese simply because they thought it a good law. All lorries had to sport a blue square on the top of the cab to denote that they were a commercial vehicle. If towing a trailer ,then they also had to show a yellow triangle on a seperate blue square( in other words both of the signs). Any car or van towing any type of trailer (including a caravan) had to show the yellow triangle on a blue backing to also show oncoming traffic that they were towing. None of these signs had to be illuminated but were much more effective if they were.
I hope this clarifies the reason behind the fact.Thats what I was told too!
Same here mate, but there were several rumours doing the rounds at the time.
I used to go to Spain quite regularly (but not Portugal) back in the early 80s, and the blue square / yellow triangle thing was in operation at that time.
I was always told it was to distinguish international from national operators but trucknet teaches us something new everyday. But to have an obscure sign that is 5 inches square on a 50’ truck is like having a Phaeng sticker on a Danish motor
What got me thinking about it, was that theres a pic on Topruns site of what looks like a mid 60s motor sporting the sign and … its on Swiss plates
Suedehead:
Wheel Nut:
dieseldave:
Dieseldogsix:
TIR Original:
Hi Guys, you’ve nearly got it correct between you. It was in actual fact a Spanish law that was sometimes used by the Portuguese simply because they thought it a good law. All lorries had to sport a blue square on the top of the cab to denote that they were a commercial vehicle. If towing a trailer ,then they also had to show a yellow triangle on a seperate blue square( in other words both of the signs). Any car or van towing any type of trailer (including a caravan) had to show the yellow triangle on a blue backing to also show oncoming traffic that they were towing. None of these signs had to be illuminated but were much more effective if they were.
I hope this clarifies the reason behind the fact.Thats what I was told too!
Same here mate, but there were several rumours doing the rounds at the time.
I used to go to Spain quite regularly (but not Portugal) back in the early 80s, and the blue square / yellow triangle thing was in operation at that time.
I was always told it was to distinguish international from national operators but trucknet teaches us something new everyday. But to have an obscure sign that is 5 inches square on a 50’ truck is like having a Phaeng sticker on a Danish motor
What got me thinking about it, was that theres a pic on Topruns site of what looks like a mid 60s motor sporting the sign and … its on Swiss plates
Hullo Suedehead,
I believe it was used all over Europe as a warning or indication that a vehicle was pulling a trailer. I can remember asking the very same question when we visited family friends just after the War. Probably in about 1946/7. I saw these signs on several vehicles then in Lille, Nord.
Cheers, Archie.
Archie Paice:
Suedehead:
Wheel Nut:
dieseldave:
Dieseldogsix:
TIR Original:
Hi Guys, you’ve nearly got it correct between you. It was in actual fact a Spanish law that was sometimes used by the Portuguese simply because they thought it a good law. All lorries had to sport a blue square on the top of the cab to denote that they were a commercial vehicle. If towing a trailer ,then they also had to show a yellow triangle on a seperate blue square( in other words both of the signs). Any car or van towing any type of trailer (including a caravan) had to show the yellow triangle on a blue backing to also show oncoming traffic that they were towing. None of these signs had to be illuminated but were much more effective if they were.
I hope this clarifies the reason behind the fact.Thats what I was told too!
Same here mate, but there were several rumours doing the rounds at the time.
I used to go to Spain quite regularly (but not Portugal) back in the early 80s, and the blue square / yellow triangle thing was in operation at that time.
I was always told it was to distinguish international from national operators but trucknet teaches us something new everyday. But to have an obscure sign that is 5 inches square on a 50’ truck is like having a Phaeng sticker on a Danish motor
What got me thinking about it, was that theres a pic on Topruns site of what looks like a mid 60s motor sporting the sign and … its on Swiss plates
Hullo Suedehead,
I believe it was used all over Europe as a warning or indication that a vehicle was pulling a trailer. I can remember asking the very same question when we visited family friends just after the War. Probably in about 1946/7. I saw these signs on several vehicles then in Lille, Nord.
Cheers, Archie.
not all over Europe but it was also used in Germany in the fifties and I think early sixties as well
I believe it was used all over Europe as a warning or indication that a vehicle was pulling a trailer. I can remember asking the very same question when we visited family friends just after the War. Probably in about 1946/7. I saw these signs on several vehicles then in Lille, Nord.
Cheers, Archie.
[/quote]
not all over Europe but it was also used in Germany in the fifties and I think early sixties as well
[/quote]
Hullo,
As you say, not all over Europe. But so far we have Portugal, Spain, France and Germany. Slowly we are getting there eh ?
Cheers, Archie.
Archie Paice:
Suedehead:
Wheel Nut:
dieseldave:
Dieseldogsix:
TIR Original:
Hi Guys, you’ve nearly got it correct between you. It was in actual fact a Spanish law that was sometimes used by the Portuguese simply because they thought it a good law. All lorries had to sport a blue square on the top of the cab to denote that they were a commercial vehicle. If towing a trailer ,then they also had to show a yellow triangle on a seperate blue square( in other words both of the signs). Any car or van towing any type of trailer (including a caravan) had to show the yellow triangle on a blue backing to also show oncoming traffic that they were towing. None of these signs had to be illuminated but were much more effective if they were.
I hope this clarifies the reason behind the fact.Thats what I was told too!
Same here mate, but there were several rumours doing the rounds at the time.
I used to go to Spain quite regularly (but not Portugal) back in the early 80s, and the blue square / yellow triangle thing was in operation at that time.
I was always told it was to distinguish international from national operators but trucknet teaches us something new everyday. But to have an obscure sign that is 5 inches square on a 50’ truck is like having a Phaeng sticker on a Danish motor
What got me thinking about it, was that theres a pic on Topruns site of what looks like a mid 60s motor sporting the sign and … its on Swiss plates
Hullo Suedehead,
I believe it was used all over Europe as a warning or indication that a vehicle was pulling a trailer. I can remember asking the very same question when we visited family friends just after the War. Probably in about 1946/7. I saw these signs on several vehicles then in Lille, Nord.
Cheers, Archie.
Cheers for that Archie. So that would have been on wagon + drags?
Hullo Suedehead,
I believe it was used all over Europe as a warning or indication that a vehicle was pulling a trailer. I can remember asking the very same question when we visited family friends just after the War. Probably in about 1946/7. I saw these signs on several vehicles then in Lille, Nord.
Cheers, Archie.
[/quote]
not all over Europe but it was also used in Germany in the fifties and I think early sixties as well
[/quote]
Hullo Suedehead,
Yes BUT obviously not Wagon and Drags as you know them, a normal size lorry then was anything from One Ton to Four Tons, ( There were vehicles much larger than that with larger trailers, but the weights were very much lower than now. The smaller lorries that there were more of, were mostly small Berliets, Citroen Camionettes, Latil’s, Panhards, Saviems or Unic’s, the tailers were just a small flatbed affair.
Cheers, Archie.