traffic lights cardiff town centre

[someonesgirl]

why do the lights by the big sleep hotel going towards the centre change to red when i get there, but only for literally 3 seconds then they go green again.......it makes it pointless to stop at all as no other traffic would even have the chance to get through!! And it makes me have to slam my brakes on and its very annoying.

[Melliexr]

A lot of junctions now have traffic lights fitted with motion detectors and/or presence detectors that change the timing of the phases. My guess is the detectors are either detecting your movement or presence, or NOT detecting traffic on the other phase, and changing the lights accordingly. Otherwise you can sit there on red while the other phase runs its maximum green time for no reason. I hope that's clear.....

[Brooksy]

With traffic lights with sensors, going back to the 70`s (old rubber spring-up type) to today`s sensors, I`ve always found that if you`re the 1st & only vehicle present, one has to reverse some yards/metres (experiment!) & then move back to the Stop line & the lights change almost immediately. May not work in busy periods!

[someonesgirl]

how very odd!