Do Speed Cameras Flash Even If You Are Not Speeding?

So, borrowed my sisters car tonight, drove solo for the first time ever since passing my driving test. Going through a 40 zone, at just over 30mph (wasn't going fast because I was looking for the place I was trying to find!!), I'm sure the speed camera flashed.

Do they flash just when you are speeding, or can they just flash when you are travelling under the speed limit?

Any help would be very much appreciated!! :confused:

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Reply 1

Laura Lou

As far as I'm aware they only flash if you're speeding, I'm afraid! :frown:

Are you 100% sure that it was a 40 zone?

edit: just because it flashed doesn't necessarily mean it had a film in it! so you might get lucky...

Reply 2

Ryan

Only flash if you're speeding.

My guess is that it was a 30 zone and your speedo said 40, meaning you were doing 36ish which should have set it off

Reply 3

richard-

I have done 36 past a camera I think it is 37 when it is set off

Reply 4

Solid_L

They say 10% of the speed limit + 2 miles an hour is what they set off at. So in a 30 mph zone, they should go off at 35 miles per hour etc. (30 + 3 + 2)

Reply 5

andy_c

Nah, it was defo 33ish in a 40 zone! I checked the speed limit because I had to go around again, as I couldn't find the place until the second time around. Plus, just after the cameras there is a mass of signs and road markings saying, 30 zone... they wouldn't be there if it was already a 30 zone.

Hope I'm wrong... was my sister's car not mine too!

Reply 6

Kyri

There is this camera I drive past often that I know for a fact flahses on random intervals as 9 times out of 10 when I have seen it flash there has been no car there whatsoever. I don't know if it's meant to do that or if it's broken, but the camera you drove past might have been like this and you just happened to be driving past when it flashed. Hopefully this is the case and you won't be receiving any fine. If you do though you should complain about the camera as there is quite a gap between 33 and 40mph.

Reply 7

pghstochaj

Lines on the floor will mean you won't face any problems aslong as it was a 40 zone.

Reply 8

Cortez

Ryan

Only flash if you're speeding.

My guess is that it was a 30 zone and your speedo said 40, meaning you were doing 36ish which should have set it off

So the speedo is saying over what you are actually doing? I didnt think it was legal for speedos to over estimate your speed :confused:

Reply 9

pghstochaj

No, they can't under-read, i.e. say you're doing 40 if you're doing 45,

Reply 10

OBScene

Cortez

So the speedo is saying over what you are actually doing? I didnt think it was legal for speedos to over estimate your speed :confused:

All spedometers overestimate your speed by 2-4mph to give you a little leeway for speed limits etc - the only ones that aren't are in traffic cops cars that are exactly calibrated every week. As such, if your speedo shows you driving 30mph, in actual fact you're going 26-28mph - and why it's safe to drive on the motorway at 80mph because your actual speed will be no more than 78mph, and you won't get prosecuted until 79mph.

It's also why an ordinary policeman can't stop you for speeding based only on their speedometer, because it's inaccurate. They need to have 2 cops saying you're speeding, or else use a laser/radar gun.

Reply 11

Cortez

pghstochaj

No, they can't under-read, i.e. say you're doing 40 if you're doing 45,

Oh yeah thats it, my bad :redface:

Reply 12

pghstochaj

hehe.

It's always a fixed percentage too on all analogue speedos as far as I am ware, typically 6-10%, not fixed mph points.

I am not sure whether digital speedos (which are driven in the same way) have different ways of presenting the information.

Reply 13

Ryan

Cortez

So the speedo is saying over what you are actually doing?

Yes.

Reply 14

dave134

pghstochaj

Lines on the floor will mean you won't face any problems aslong as it was a 40 zone.

If your sister does get an NIP (Notice of Intended Prosecution) then she should name you as the driver, then when you recieve your own you should say that you were driving but believe you were not speeding and ask them to double check the lines etc.

If you were under the speed limit then she shouldn't get the NIP in the first place but mistakes can happen, thats why the lines are painted on the road in the first place.

Reply 15

Bossworld

Solid_L

They say 10% of the speed limit + 2 miles an hour is what they set off at. So in a 30 mph zone, they should go off at 35 miles per hour etc. (30 + 3 + 2)

That used to be the case with mobile cameras but isn't anymore. I've seen tickets for 34mph so it's not the case, but you're right it's not set at 30 otherwise it would go off too often.

Car speedos over-read more/less depending on tyre size. There's a percentage calculator on the internet somewhere, you're supposed to keep any tyre/wheel change down to below a certain percentage. My car came on 185/65/14 originally but then went on 15" wheels with 195/55/15 tyres. Changed down to 195/50/15 and the speedo is ever so slightly more out from what I've heard but the tyres are cheaper so it makes sense.

borrow a sat nav device if you get a chance, found my car is about 3mph out from what the speedo says.

edit: oh and speed cameras can 'flash' when someone is driving behind you and wants to put you off by flashing their headlights twice in quick succession :smile:

Reply 16

Pseudomuse

it might have been a reflection from the sun or a head light. if it flashed you, then it would have flashed twice!

Reply 17

L0RA

No ones thought it was a car coming in the opposite direction setting it off then?

Reply 18

Pookie

To answer the question they can flash when your going past and not speeding. Some jusdt flash at random intervals. It is only when you are flashed twice when it takes a picture. If you weren't speeding then don't worry about it.

I have been flashed doing 10mph through 30 before now.

Reply 19

flyboy123

There is one thing it could have been. Are you 110% sure that it was the camera that flashed. You say you were doing 33ish mph. Due to your speedo that probably means you were doing around 30mph. I have known of people who would be anoyed that someone is driving 10mph under the limit and thereby holding them up. Someone i know flashes his headlights twice when people go excessivly slowly through speed cameras.

I know thats really bad but i have heard of it happening.

Is that possible?