Planner1 Â Â 424 #25 Posted April 19, 2012 Why do we need 4- 8 green lights at a pedestrian crossing telling us to go forward? All we need is a red light telling us to stop when a pedestrian presses a button. Each site is designed to have the number of signal heads required for safe operation and good visibility. Some redundancy is needed in case one or more lamps are out. Â In your scenario, what happens when the single red lamp is broken? The pedestrian still sees a green man. The driver sees nothing and thinks the signals are all out. Multiple signal heads are provided in the interests of safety Share this post Link to post Share on other sites Share this content via...
Planner1 Â Â 424 #26 Posted April 19, 2012 I think the tram gets preference, so that possibly a reason round Hillsborough. Trams get absolute priority at most signalled junctions they pass through. Â Buses can also get priority but the system used for them is much more sophisticated than the tram. It's a GPS based system. Ticket machines on most buses are GPS enabled an a central computer system accurately tracks them and checks against the timetable whether they are behind schedule or not. If they are behind schedule by more than a preset amount, they get priority at traffic signals. If they are on schedule, they don't. Share this post Link to post Share on other sites Share this content via...
monkey104   10 #27 Posted April 19, 2012 In your scenario, what happens when the single red lamp is broken? The pedestrian still sees a green man. The driver sees nothing and thinks the signals are all out. Multiple signal heads are provided in the interests of safety  I see your reasoning but as in some cases there are four sets of lights continuously illuminated, so if one was to fail there would still be 3 more showing.  As I drive around the city a lot during the night I sometimes wonder at the cost of illuminating all the unused/uneccessary traffic signals in Sheffield. Share this post Link to post Share on other sites Share this content via...
Taximark   10 #28 Posted April 20, 2012 No signals in Sheffield stay red for 10 mins at any time of day or night when a vehicle is present (unless they are faulty). The most you will normally ever get is a couple of minutes, most sites will be 60-90 seconds.  Tongue in cheek planner1, but lets say for argument sake that Bradfield Rd stays red for three long minutes then change but 15 seconds later back to red again, carry on up holme lane again - red light for three long minuted again - see the trend? Share this post Link to post Share on other sites Share this content via...
Taximark   10 #29 Posted April 20, 2012  Traffic signal installations are quite complex. There's a delicate box full of sensitive electronics which controls it all and communicates with the central computer and there is hundreds of metres of cabling with connections at every signal pole, signal head, pedestrian signal and push button. Occasionally, intermittent faults can develop, which can be extremely difficult to pin down. The faults can also be with the electricity supply. Even quite small fluctuations in the power supply can make the signals go off.  They have been having problems at that site for a while and it's clearly difficult to find the exact cause.   These set of lights have been faulty for about 3-4 months, you would of thought for one of the most busiest roads in Sheffield this would of been rectified by now. Share this post Link to post Share on other sites Share this content via...
Taximark   10 #30 Posted April 20, 2012 I'd bet that if you time it with a stopwatch next time you are waiting, it's nowhere near 5 minutes. I use that junction quite a bit at all times of day and night an have never seen anything of that nature. All signals on the main routes in Sheffield are synchronised as much as they can be, mostly by a central computer which controls most of the signals in the city. Remember, you can only synchronise in one direction, so if you are travelling the opposite way, you will often not get good progression.  The lights are red for ages here, you say 2-3 mins? seems like 10 when you're in a taxi pal, what i'm saying is lights are changing to red for no reason whatsoever.  I waited at these lights whilst no traffic flowed the other way and as soon as a car came the other way the lights then stopped him, lol - working lovely. Share this post Link to post Share on other sites Share this content via...
BarryRiley   10 #31 Posted April 20, 2012 Or even after 12pm, why not adopt a 'flashing amber'? meaning proceed with caution. Most European countries do it.  I love this idea. Why have we not caught on to this. It would ease traffic congestion, reduce pollution and improve the economy. Share this post Link to post Share on other sites Share this content via...
maloney111 Â Â 10 #32 Posted April 20, 2012 there's that many traffic lights in sheffield, it would put blackpool illuminations to shame!! Share this post Link to post Share on other sites Share this content via...
BarryRiley   10 #33 Posted April 20, 2012 there's that many traffic lights in sheffield, it would put blackpool illuminations to shame!!  True, I'm guessing it's because of how the roads have been laid out. For example, I'm not sure every parallel road needs to join Penistone Road so frequently leading to the traffic light mess it is at the moment. Share this post Link to post Share on other sites Share this content via...
maloney111 Â Â 10 #34 Posted April 20, 2012 True, I'm guessing it's because of how the roads have been laid out. For example, I'm not sure every parallel road needs to join Penistone Road so frequently leading to the traffic light mess it is at the moment. Â well said, and a good example! Share this post Link to post Share on other sites Share this content via...
Eater Sundae   12 #35 Posted April 20, 2012 True, I'm guessing it's because of how the roads have been laid out. For example, I'm not sure every parallel road needs to join Penistone Road so frequently leading to the traffic light mess it is at the moment.  I'm sure I remember someone, on another thread several months ago, blaming congestion on the fact that we have closed off so many side roads that joining traffic is forced into a few junctions. Share this post Link to post Share on other sites Share this content via...
Planner1 Â Â 424 #36 Posted April 20, 2012 I love this idea. Why have we not caught on to this. It would ease traffic congestion, reduce pollution and improve the economy. Can you point out what traffic congestion it would ease in the middle of the night, because I am not aware that there is any. Â Also, how is saving you a few seconds on your way home after midnight going to aid the economy? Share this post Link to post Share on other sites Share this content via...