Hacker News Reader

Comment by mortov | Hacker News Reader

Often (but not always) in the UK, the laser is accompanied by video footage which shows where the beam has been trained and it is a combination of both the video and laser reading (shows on the video) which is the evidence. (all tripod mounted - so I suspect many of the issues detailed are well known). Sounds like that would give good supporting evidence for a challenge.

However, traffic violations is most places are about revenue raising so anything which reduces the opportunities - like accuracy and fairness - are unlikely to get much of a look in.

edit: for clarity, it looks like this http://www.mirror.co.uk/news/uk-news/pictured-speeding-motor...

also referenced in my reply below.

View on HN

In the UK, speed cameras seem to be accompanied by road markings:

http://southport.qlocal.co.uk/southport/news_list/New_Speed_...

I always assumed that the radar was only for deciding to take and submit the pictures, the actual speed measurement (especially if challenged) would be done using the markings on the road.

That only requires the speed camera to have a reliable to 1/100 second clock which isn't exactly rocket science.

Static cameras have markings and 2 pictures are taken, normally 1/3 of a second apart. Activation is either radar or in-road inductive wiring. Neither are foolproof and pictures are supposed to be manually checked but often are not with results like this http://www.bbc.co.uk/news/uk-england-norfolk-21264281 where a claimed 50mph was actually 18 mph)

Someone did manage to appeal because they'd incorrectly painted the markings too close together. You have to check everything ! :D

how can a video possibly show where a laser is pointed at from > 1,000ft away? that seems unreasonable.

The video is required to zoom to show the driver of the vehicle as well for identification purposes. It prevents people claiming they were not the driver.

(e.g. it looks like this http://www.mirror.co.uk/news/uk-news/pictured-speeding-motor...)

That image may reasonably prove it was not a woman driving the vehicle, but no way can that prove it was the actual driver (or anyone's identity). It's way too blurry and pixelated. Also, a LIDAR beam shouldn't be pointed at a sloped window, so I doubt it actually proves where the beam was pointed at either.

I don't see how it could even prove it was not a woman driving. I'm barely comfortable asserting that it shows a human face.

Reply on news.ycombinator.com