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Always thought that was an urban legend. I'm not from the US, however in New Zealand the lights would never change as an ambulance/police car went past. They'd

Always thought that was an urban legend. I'm not from the US, however in New Zealand the lights would never change as an ambulance/police car went past. They'd just slow down as everyone moved out of their way. Have witnessed this also for our Prime Minister driving past with a convoy of police and black SUV's.

gamerdonkey 12y ago
In the US, these are certainly real. Apparently, some did use strobe lights to signal the traffic lights. http://en.wikipedia.org/wiki/Traffic_signal_preemption http://en.wikipedia.org/wiki/Traffic_signal_preemption I vaguely have memories of the state legislator having to pass new laws after the devices were installed because it was not technically illegal to have the emitter in your vehicle.
- tdfx 12y ago
  Usually only certain traffic signals are equipped with the detectors, but they do in fact use strobe lights to trigger the light switch and it does happen immediately. It doesn't work with any emergency lights, though -- a separate, specific strobe light be must installed to trigger the signal.
contingencies 12y ago
Just across the pond in Sydney, Australia, one of my earliest jobs was related to the traffic control systems at the Roads and Transit Authority (RTA). I do have the distinct impression that they had wireless communications allowing reprogramming of lights by emergency service vehicles. They also had zero authentication ISDN-based video dialups on major intersections, under-road sensor loops to compile traffic volumes, and had kept a VAX running right through to ~2001 and later. Most of that's probably gone now, but I suppose the wireless traffic manipulation is still about.
- coffeecheque 12y ago
  Was it the SCATS system by chance? http://www.scats.com.au/ http://www.scats.com.au/
  - contingencies 12y ago
    Yep. SCATS is the name of the base system, very successfully exported to many countries overseas, some of which became our later customers. We were focused on third-party provision of complementary products.

gamerdonkey 12y ago

In the US, these are certainly real. Apparently, some did use strobe lights to signal the traffic lights. http://en.wikipedia.org/wiki/Traffic_signal_preemption http://en.wikipedia.org/wiki/Traffic_signal_preemption I vaguely have memories of the state legislator having to pass new laws after the devices were installed because it was not technically illegal to have the emitter in your vehicle.

tdfx 12y ago
Usually only certain traffic signals are equipped with the detectors, but they do in fact use strobe lights to trigger the light switch and it does happen immediately. It doesn't work with any emergency lights, though -- a separate, specific strobe light be must installed to trigger the signal.

contingencies 12y ago

Just across the pond in Sydney, Australia, one of my earliest jobs was related to the traffic control systems at the Roads and Transit Authority (RTA). I do have the distinct impression that they had wireless communications allowing reprogramming of lights by emergency service vehicles. They also had zero authentication ISDN-based video dialups on major intersections, under-road sensor loops to compile traffic volumes, and had kept a VAX running right through to ~2001 and later. Most of that's probably gone now, but I suppose the wireless traffic manipulation is still about.

coffeecheque 12y ago
Was it the SCATS system by chance? http://www.scats.com.au/ http://www.scats.com.au/
- contingencies 12y ago
  Yep. SCATS is the name of the base system, very successfully exported to many countries overseas, some of which became our later customers. We were focused on third-party provision of complementary products.