Belt and braces Welsh speed detection?
Discussion
On the westbound A55 this morning, at the average speed monitored zone near Rhuallt, I was surprised to see a speed(?) camera van with its rear windows open in the lay-by at the bottom of the hill. Nobody was appearing to be exceeding the limit.
Both seem more than a little pointless individually, but if it was a speed camera van, having both simultaneously appears ridiculous.
Well, at least it wasn't on another road.
Both seem more than a little pointless individually, but if it was a speed camera van, having both simultaneously appears ridiculous.
Well, at least it wasn't on another road.
They do this kind of thing for many reasons -
If its the downhill section they will be looking for people point and brake tailgaiting through the average speed section, people moving around not tracked by the fixed infrastructure get caught but most likely they are looking for non-speeding offences because the vans have cameras to look for you using you phone, not wearing seatbelts and stuff like that.
If its the downhill section they will be looking for people point and brake tailgaiting through the average speed section, people moving around not tracked by the fixed infrastructure get caught but most likely they are looking for non-speeding offences because the vans have cameras to look for you using you phone, not wearing seatbelts and stuff like that.
bigothunter said:
Rh14n said:
Seeing as there were two majorly disruptive RTCs in that area yesterday perhaps it shouldn't surprise us.
Which must have been caused by breaking the speed limit 
yourself.craigjm said:
They do this kind of thing for many reasons -
If its the downhill section they will be looking for people point and brake tailgaiting through the average speed section, people moving around not tracked by the fixed infrastructure get caught but most likely they are looking for non-speeding offences because the vans have cameras to look for you using you phone, not wearing seatbelts and stuff like that.
Exactly this. It regularly has a camera van there.If its the downhill section they will be looking for people point and brake tailgaiting through the average speed section, people moving around not tracked by the fixed infrastructure get caught but most likely they are looking for non-speeding offences because the vans have cameras to look for you using you phone, not wearing seatbelts and stuff like that.
Because if someone is speeding, they can be given twice as many tickets.
And presumably because many people speed up once they've passed what they know in normally the last camera.
Also, thinking about it, people probably speed up as they go down the hill, so if you pass the first camera at 70mph and the second at 80mph (assuming constant acceleration) they'll clock you at 75mph average speed and you won't get a ticket, but if you pass the van at 80mph, you will get a ticket.
And presumably because many people speed up once they've passed what they know in normally the last camera.
Also, thinking about it, people probably speed up as they go down the hill, so if you pass the first camera at 70mph and the second at 80mph (assuming constant acceleration) they'll clock you at 75mph average speed and you won't get a ticket, but if you pass the van at 80mph, you will get a ticket.
LotsOfLaughs said:
Because if someone is speeding, they can be given twice as many tickets.
And presumably because many people speed up once they've passed what they know in normally the last camera.
Also, thinking about it, people probably speed up as they go down the hill, so if you pass the first camera at 70mph and the second at 80mph (assuming constant acceleration) they'll clock you at 75mph average speed and you won't get a ticket, but if you pass the van at 80mph, you will get a ticket.
That's not how they work, you could go past the first camera at 200mph and drive 99% of the way at that speed then stop for a picnic on the hard shoulder 1cm before the 2nd camera, set off again a short (or long, you do the math) while later and never get a ticket.And presumably because many people speed up once they've passed what they know in normally the last camera.
Also, thinking about it, people probably speed up as they go down the hill, so if you pass the first camera at 70mph and the second at 80mph (assuming constant acceleration) they'll clock you at 75mph average speed and you won't get a ticket, but if you pass the van at 80mph, you will get a ticket.
Frane Selak said:
LotsOfLaughs said:
Because if someone is speeding, they can be given twice as many tickets.
And presumably because many people speed up once they've passed what they know in normally the last camera.
Also, thinking about it, people probably speed up as they go down the hill, so if you pass the first camera at 70mph and the second at 80mph (assuming constant acceleration) they'll clock you at 75mph average speed and you won't get a ticket, but if you pass the van at 80mph, you will get a ticket.
That's not how they work, you could go past the first camera at 200mph and drive 99% of the way at that speed then stop for a picnic on the hard shoulder 1cm before the 2nd camera, set off again a short (or long, you do the math) while later and never get a ticket.And presumably because many people speed up once they've passed what they know in normally the last camera.
Also, thinking about it, people probably speed up as they go down the hill, so if you pass the first camera at 70mph and the second at 80mph (assuming constant acceleration) they'll clock you at 75mph average speed and you won't get a ticket, but if you pass the van at 80mph, you will get a ticket.
If you go past point A at 70 and point B at 80, with a constant rate of acceleration, your average speed between A and B is 75.
LotsOfLaughs said:
Hence why I said "assuming constant acceleration".
If you go past point A at 70 and point B at 80, with a constant rate of acceleration, your average speed between A and B is 75.
Fair enough, a lot of people assume it takes one speed reading at A and another at B and then averages the two readings.If you go past point A at 70 and point B at 80, with a constant rate of acceleration, your average speed between A and B is 75.
LotsOfLaughs said:
Hence why I said "assuming constant acceleration".
If you go past point A at 70 and point B at 80, with a constant rate of acceleration, your average speed between A and B is 75.
Fun fact of the day.If you go past point A at 70 and point B at 80, with a constant rate of acceleration, your average speed between A and B is 75.
You can be driving at a fixed speed (say 70mph) and you could still be constantly accelerating.
LotsOfLaughs said:
Because if someone is speeding, they can be given twice as many tickets.
If the average speed camera and the mobile detected excess speed there would be one prosecution for speeding with 2 sets of evidence.LotsOfLaughs said:
And presumably because many people speed up once they've passed what they know in normally the last camera.
Also, thinking about it, people probably speed up as they go down the hill, so if you pass the first camera at 70mph and the second at 80mph (assuming constant acceleration) they'll clock you at 75mph average speed and you won't get a ticket, but if you pass the van at 80mph, you will get a ticket.
The reason for the mobile unit is likely to be because some drivers slow for the first and second cameras and speed up between the cameras, they are also probably speeding before and after the average camera system.Also, thinking about it, people probably speed up as they go down the hill, so if you pass the first camera at 70mph and the second at 80mph (assuming constant acceleration) they'll clock you at 75mph average speed and you won't get a ticket, but if you pass the van at 80mph, you will get a ticket.
Seems like the mobile unit is a sensible tactic.
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