What are these black lines in the road?

[Wafflesmk2]

Similar to this


But more square. They are the same style as traffic light ones, but usually rectangular instead of being diagonal like traffic light ones.

There's some near me, nowhere near any junction, and there's a grey metal box on the verge next to them which i assume is connected.

It's not the raised ones that are temporary and monitor speeds or traffic numbers.

[ShayneJ]

probably for monitoring traffic volume flow and average speed
for DOT or the traffic data co's like traffic master

[sebhaque]

Some of the ones near traffic lights are sensors that detect any stationary/approaching cars so at quiet times (e.g. 3am) the lights should be green for approaching traffic, without having to wait for a timer.

Of course, all that happens is that you slow down at an empty red and just as you've come to a dead stop, the light goes amber

[Pet Troll]

Do you have a google maps link to where they are? Would be interested to see as I think I have only ever seen them near/on junctions.

[Fastdruid]

Or you're on a bike and it refuses to notice you. Until a car comes along and they instantly go green. Grrrr

[Wafflesmk2]

Pet Troll said:

Do you have a google maps link to where they are? Would be interested to see as I think I have only ever seen them near/on junctions.

Road going the other way is the same, until you hit a roundabout, around 1/4 of a mile down.

[Caesar9]

I was going to say that they are just repairs to the road from a pipe repair or something and sealed with tar but you would of thought that the repaired part would be a different colour to the rest of the road.
I can't think of any other reason than that from that picture.

[E38Ross]

traffic lights near by? possibly for them.

[BigBadDavid]

They are sensors, either to detect traffic near junctions or for monitoring the temperature of the road surface. If they are temperature sensors you often see a anemometer (wind speed sensor) nearby.

[R60EST]

What is that grey box near the lamp post. If it's not a bin it's probably connected to the lines in the road to collect data about traffic flow etc

[jackh707]

Fastdruid said:

Or you're on a bike and it refuses to notice you. Until a car comes along and they instantly go green. Grrrr

When riding the bike late at night I have fallen victim to this on my route home, is there a period of time after which its deemed acceptable to go through a red light? I have waited 5 minutes + at an empty junction in the dead of night without seeing a car pass before.

[Richspec]

Known in the trade as 'loops'

http://en.wikipedia.org/wiki/Induction_loop

as has been said they're used for traffic monitoring.

The road ice detection sensors are a small sensor block in the wheel track at the end of a single cable and are found next to a full weather station that can include wind, temperature, humidity and visibility sensors, some also have cameras but they monitor the road purely and are NOT speed cams!


Rich

Field Service Tech for Vaisala.

[McSam]

jackh707 said:

When riding the bike late at night I have fallen victim to this on my route home, is there a period of time after which its deemed acceptable to go through a red light? I have waited 5 minutes + at an empty junction in the dead of night without seeing a car pass before.

I've actually had to run one in a car.. As if a Mk3 Mondeo isn't big enough! I was pulled up at the lights at 3am on an airport run for two minutes or so. Knowing the lights well enough to know they're sensor controlled and that that was too long, I reversed fifty yards and drove up to them sharply again, nothing!

[5lab]

seperate but similar question, whats with the seperate units they have near gatsos these days? normally about the same height, grey, 2-3m in front of the gatso and some sort of light or camera unit on the top?

[Sam.F]

Could possibly be DS2 loops from the description?