Can someone tell me how average speed cameras work
Discussion
Basically, you pass a camera & it snaps your plate.
A bit later you pass another one and it snaps your plate again. Compares the times against the known distance and works out your average speed.
Now, as to whether the software is dumb enough to assume that a vehicle will stay in one lane forever or can't cope with missing a vehicle at camera 2 but seeing it again at camera 3 isn't something I can answer. I would be very very surprised if this was the case (unless the coders were also petrolheads!
)
A bit later you pass another one and it snaps your plate again. Compares the times against the known distance and works out your average speed.
Now, as to whether the software is dumb enough to assume that a vehicle will stay in one lane forever or can't cope with missing a vehicle at camera 2 but seeing it again at camera 3 isn't something I can answer. I would be very very surprised if this was the case (unless the coders were also petrolheads!
)Edited by pdV6 on Tuesday 16th October 10:36
pdV6 said:
Now, as to whether the software is dumb enough to assume that a vehicle will stay in one lane forever or can't cope with missing a vehicle at camera 2 but seeing it again at camera 3 isn't something I can answer.
It's not that dumb, but it's only type approved to operate in one lane between pairs of cameras, that said you never know how the cameras are paired; eg.C1 ------ C2 ------ C3 ------ C4
could be paired;
C1 - C2, C3 - C4
or
C1 - C3, C2 - C4
or
C1 -C4, C2 - C3
If you see what I mean.
Something that puzzles me though......
Two SPECS cameras 1 mile apart. 40 limit.
Say you do 20mph through the first, and maintain this speed for the first 1/2 mile.
If they are true 'average' speed detectors (and nothing else), you should be able to do (much) more than 40mph through the second camera, as your average speed over the set distance has not exceeded 40!
Or is each camera capable of nabbing you independently for exceeding the set limit?
Two SPECS cameras 1 mile apart. 40 limit.
Say you do 20mph through the first, and maintain this speed for the first 1/2 mile.
If they are true 'average' speed detectors (and nothing else), you should be able to do (much) more than 40mph through the second camera, as your average speed over the set distance has not exceeded 40!
Or is each camera capable of nabbing you independently for exceeding the set limit?
EU_Foreigner said:
Only when there is a traffic jam at the beginning bit (as everyone goes sooooo slow then) you can catch up on the average later on ...
The trouble with this is that there are often a few pairs of cameras along the whole of the restricted road...so i guess if you exceed the average speed limit through both pairs, one after the other, there's a possibility of two NIPs, same as if you go through multiple GATSOs.Jeremy Kyle said:
Do you know when they are due to approve the SPECS?
Sorry, no. I don't know if its something they are working on currently or whether there are even plans for it in the future.In terms of basic economics, though, I'd have thought the powers that be would be rubbing their hands with glee if they thought they could enforce three of four lanes of motorway with just two cameras..
pdV6 said:
nelly1 said:
Something that puzzles me though......
Say you do 20mph through the first, and maintain this speed for the first 1/2 mile.
Something that puzzles me: Why on earth you'd want to do that?Say you do 20mph through the first, and maintain this speed for the first 1/2 mile.
Either that or just for fun. A sort of impromptu drag race to the last camera knowing you won't get a NIP.
Unless they act as normal cameras as well, which no-one has answered yay or nay to yet......
pdV6 said:
nelly1 said:
Unless they act as normal cameras as well, which no-one has answered yay or nay to yet......
I believe not - all they have to do is snap your pic and record the time. No radar / induction loops to measure your instantaneous speed.
The device detects when a vehicle enters an enforcement zone and when it exits the enforcement zone. It knows the time taken & distance covered between the entry and exit points which enables calculation of the average speed.
The SPECS / SVDD system does not function as an instantaneous speed detection device.
pdV6 said:
nelly1 said:
Unless they act as normal cameras as well, which no-one has answered yay or nay to yet......
I believe not - all they have to do is snap your pic and record the time. No radar / induction loops to measure your instantaneous speed.At any point if it calculates a speed over the limit you get an NIP. Presumably the evidence is two date/time stamped images of your car.
I have no idea how long the images/dates/times are stored. I expect only a few minutes is necessary - with the occasional "offence evidence" getting written away somewhere else.
Here's the thing. So far I have only ever encountered SPECS cameras in roadworks. Enforcing a speed limit designed to protect workers. Sure I know they do it 24/7 and its only necessary 8 hours a day but the cameras are clearly signed and really, really obvious.
They even have big signs saying AVERAGE speed cameras.
There is no excuse for getting caught by any I've seen so far. None at all.
And yet? How many people do you see braking for them! I mean? DIDN'T YOU GO TO SCHOOL? DON'T YOU KNOW THE MEANING OF THE WORD "AVERAGE!??!".
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