Speed cameras and dual carriageways

Lauren330727

Hi, I was driving on a dual carriageway yesterday (100kph limit) was just after passing a truck and had moved back into the left hand lane, the jeep behind me stayed in the right hand lane and was going past me when I spotted the speed van on the hard shoulder . I was doing about 105 kph on the speedometer and he was going past fairly quickly so reckon he was doing a lot more. I'm just wondering how the cameras work at judging speed when two cars are coming towards them like that?

Gordon Minard

It's crazy I think having speed cameras on Motorways / Dual Carriageways!

Some day they will cause a pile up! People slam on the brakes when they see the camera and the poor unfortunate behind them ( me 2 years ago ) finshes up running into the back of them!

No speed limits on Motorways - like the Autobahn!

Little CuChulainn

They focus a camera on each lane. If you were only 105 in a 100 I wouldn't worry too much.

Peregrinus

Some of the cameras take two images with a short but precise interval between them. By comparing how much a vehicle shifts between the two images they know how fast it is going. They can do this for each vehicle in the picture.

Victor

Gordon Minard wrote: »

It's crazy I think having speed cameras on Motorways / Dual Carriageways!

Not counting dual carriageways. at least 7 people have been killed on motorways in the last year.

Date Time County Town Location Age Gender User type Vehicle Other vehicle(s) Garda website News website
18/12/13 19:00 Galway County Athenry M6 at Newford, Athenry 5 Female Passenger Car 2 cars www.garda.ie/Controller.aspx?Page=12430 & www.garda.ie/Controller.aspx?Page=12408 & www.garda.ie/Controller.aspx?Page=12396 www.rte.ie/news/2013/1225/494735-rta/
26/01/14 21:00 Tipperary (North) Roscrea M7 at Junction 22 near Roscrea 18 Male Driver Car - www.garda.ie/Controller.aspx?Page=12587&Lang=1 www.rte.ie/news/2014/0127/500348-rta-roscrea-tipperary/
27/03/14 22:00 Laois Portlaoise Portlaoise Bypass 47 Male Driver Car - www.garda.ie/Controller.aspx?Page=12960&Lang=1 ???
27/05/14 17:00 Fingal Swords J3-4, M1 motorway 50 Male Pedal cyclist Pedal cycle Car www.garda.ie/Controller.aspx?Page=13726&Lang=1 www.rte.ie/news/2014/0727/633452-rtc/
30/07/14 09:00 DL-R Shankill M11 at Loughlinstown 23 Male Driver Car - www.garda.ie/Controller.aspx?Page=13743&Lang=1 www.breakingnews.ie/ireland/young-man-dies-after-loughlinstown-collision-637831.html
11/08/14 14:40 Cork County Fermoy M8 northbound between Junctions 14 & 13 (Mitchelstown & Fermoy) 28 Male Driver Car 4x4 www.garda.ie/Controller.aspx?Page=13822&Lang=1 www.irishtimes.com/news/ireland/irish-news/man-28-dies-after-car-crashes-on-m8-in-co-cork-1.1894899
23/10/14 20:45 Kilare Kilare Northbound on M7 at Kildare, just north of at junction 13 ??? Female Car user Car Cars ??? www.irishtimes.com/news/ireland/irish-news/woman-dies-after-multi-vehicle-collision-involving-garda-car-1.1975081 & www.rte.ie/news/2014/1023/654502-kildare/

Gordon Minard wrote: »

Some day they will cause a pile up! People slam on the brakes when they see the camera and the poor unfortunate behind them ( me 2 years ago ) finshes up running into the back of them!

(a) People need to obey the law (admittedly, sometimes the law needs changing). (b) Are there a material number of collisions at such places?

No speed limits on Motorways - like the Autobahn!

If you want that, how about a driving test like the German one? I think it take about two years total. And German-style traffic policing?

Peregrinus

Gordon Minard wrote: »

It's crazy I think having speed cameras on Motorways / Dual Carriageways!

Some day they will cause a pile up! People slam on the brakes when they see the camera and the poor unfortunate behind them ( me 2 years ago ) finshes up running into the back of them!

I have to say that accident is not caused by the speed camera. It is caused by the person who is driving too close to the vehicle in front of him, and/or is failing to keep a proper lookout. Not looking at anyone in particular

plodder

Peregrinus wrote: »

Some of the cameras take two images with a short but precise interval between them. By comparing how much a vehicle shifts between the two images they know how fast it is going. They can do this for each vehicle in the picture.

I could be wrong, but I think that's the original type of fixed "Gatso" camera, because it depends on calibration markings painted on the road surface. I'm not sure how you would determine the distance otherwise. I'm guessing the Gosafe vans use high frequency radio (radar) pulses.

It's something I've wondered about also - how accurate they would be in mutli-lane situations. There's a dearth of information about them available to the public and not any evidence that I see that they test them for accuracy (maybe they do, maybe they don't).

Markcheese

Gordon Minard wrote: »

It's crazy I think having speed cameras on Motorways / Dual Carriageways!

Some day they will cause a pile up! People slam on the brakes when they see the camera and the poor unfortunate behind them ( me 2 years ago ) finshes up running into the back of them!

No speed limits on Motorways - like the Autobahn!

Not all dual carraigeways are motorways, and most busy motorways wouldn't suit no speed limits ... The m50 is probably our busiest motorway and it'd be carnage if you took away the speed limit ..