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Old 04-25-2018, 01:42 PM
 
938 posts, read 410,568 times
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Its the 21st century and we often hear of futuristic technologies such as self driving cars and even flying or hover cars. Though in reality we seem far from such technology. We seem to be far behind in managing our traffic flow using our existing technology While we hear of Intelligent transportation system with dynamic traffic management. It seems traffic signal and control technologies seems pretty obsolete in most areas of the world even where technology is very advanced. And not very dynamic to traffic conditions.

I remember being in LA where there are traffic lights that allow either a protected left turn phase or a mix left turn yield on green ball phase for all four directions. Though I remember seeing at such an intersection how the left turn lane was blocked off that day with no left turn signs yet the left turn arrow still comes on for a minute along with northbound phase green ball every time the light cycles before allowing the south bound to proceed despite no one being allowed to turn left. And sometimes I witness traffic agents manually stop north bound traffic with the green ball to allow southbound to turn left eastbound as the southbound for some reason don't get a protected left turn arrow before the light turns red. I just wonder why not just have the signal skip the left turn phrase on northbound but include a protected left turn arrow phase for the southbound side instead as they, unlike northbound traffic are allowed to left turn.

Interesting I see with all this technology we still cannot have dynamic "green waves" for first responders, motorcades, parades, and processions, where the light would stay green on a prescribed route until the entire group goes through the intersections. Currently they still have to do the risky cross on red light manuever. While we do have traffic light preemption technology but there are a lot left to be desired and they seem to be the exception than the norm in most areas. I noticed how come in technology ridden cities like ones in Japan or Korea first responders still have to beg for traffic to let them proceed through the red light. You'd think as innovative as they are, they would have the technology to change traffic lights a long time ago.

Wouldn't it be best if we have a dynamic routing system aka Dynamic route Clearance based on traffic condition and control the lights accordingly. Response times will be much shorter with much less disruption to traffic if they could work with the timing of the lights. rather than interrupt the traffic patterns abruptly which takes many minutes to get back to normal and slows down response times of those who's minutes count. If so whats holding most cities back especially very advanced looking cities?

Last edited by citizensadvocate; 04-25-2018 at 02:16 PM..
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Old 04-26-2018, 11:15 AM
 
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Once SD cars take over the roads, over the course of the next 10-20 yrs, traffic lights will become a thing of the past, but I would agree that the ones in use today seem to cause more traffic than they alleviate.

I drive alot for work and its mostly city driving, A common problem I see is traffic lights on the main roads, are set up (timed) so if you get one red light, you will get red lights at the next few intersections as well, seems like it would be easy to time them so the main roads people have all green, as to keep traffic moving.

Timing seems to be main problem with lights I see, another example, at an intersection, cars on the side street will have a green turning light, coming onto the main road, but the very next intersection, the light will be red, causing all those cars to back up, if this light were green, traffic would not build up from those turning onto the main road.
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Old 04-26-2018, 01:11 PM
 
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I think it's probably just an infrastructural issue. You see how long it takes to get road work done sometimes and it's no surprise that old, but functional tech isn't being replaced.
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Old 04-26-2018, 02:16 PM
 
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Quote:
Originally Posted by citizensadvocate View Post
I remember being in LA where there are traffic lights that allow either a protected left turn phase or a mix left turn yield on green ball phase for all four directions. Though I remember seeing at such an intersection how the left turn lane was blocked off that day with no left turn signs yet the left turn arrow still comes on for a minute along with northbound phase green ball every time the light cycles before allowing the south bound to proceed despite no one being allowed to turn left. And sometimes I witness traffic agents manually stop north bound traffic with the green ball to allow southbound to turn left eastbound as the southbound for some reason don't get a protected left turn arrow before the light turns red. I just wonder why not just have the signal skip the left turn phrase on northbound but include a protected left turn arrow phase for the southbound side instead as they, unlike northbound traffic are allowed to left turn.
If you have noticed those metal strip embedded in the road at intersections that is what makes the lights "smart". They detect metal through magnetism, it's mostly reliable and cost effective. It's not without problems, motorcycles for example have been known to not trigger it.


Quote:
, they would have the technology to change traffic lights a long time ago.
That is something available, no idea why they would have it.

Quote:
Wouldn't it be best if we have a dynamic routing system aka Dynamic route Clearance based on traffic condition and control the lights accordingly.
You need a lot of traffic data for this, such things are coming with AI driven cars. When fully implemented roads/lanes won't even need direction of travel.

Quote:
If so whats holding most cities back especially very advanced looking cities?
You do these thing but it costs money.
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Old 04-27-2018, 12:49 AM
 
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Sorry when i mentioned Dynamic route clearance i should have mentioned it’s actually for emergency services. It goes beyond just turning lights to favor the direction of the fire or ambulance but it actually holds lights green along the route it travels to the emergency.
Many streets already have traffic sensors and cams and gps technology has come a long way in searching for routing with regards to traffic conditions. A kind of setting up a “green wave” for them. “Green waves” actually work in some areas.

Though you are right about the loops, I didn’t notice the loops on the ground on that particular intersection which was somewhere In downtown LA.
The traffic signals on both sides of that intersection have five light holes which allows a green ball and a left arrow or a green ball without left arrow. Or left turn after yield on green. Apparently the lights in that case were pre set to whether it would include a protected left turn phase or not. Rather than on demand. If the light was on demand with the loops the left turn light for northbound should never had came on since ther were no cars on the blocked left turn lane to trigger it.

Interestingly despite being technology Mecca most Japanese cities or Asian cities hardly any cities do even basic traffic signal premption for first responders. You’d think they would have mastered it first.

Last edited by citizensadvocate; 04-27-2018 at 12:58 AM..
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Old 04-27-2018, 09:25 PM
 
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I am driving on the main road at 3:AM. There is no traffic at the little cross roads ahead of me, yet the lights on main road keep turning red. I can't think of any logical explanation. Is it possible that somebody working at traffic control gets bored and start playing with the lights?
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Old 04-28-2018, 03:54 PM
 
26,814 posts, read 38,068,160 times
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Quote:
Originally Posted by davidt1 View Post
I am driving on the main road at 3:AM. There is no traffic at the little cross roads ahead of me, yet the lights on main road keep turning red. I can't think of any logical explanation. Is it possible that somebody working at traffic control gets bored and start playing with the lights?
Those lights are probably on timers with no detection set up for oncoming cars. In Las Vegas I never see anything to adjust signals for varying traffic patterns. The lights seem to change on a single, timed pattern.

I have found that if I am at a red light on a main street and i drive 10 mph over the limit when I leave the intersection I will make all the lights ahead of me. In my opinion this shows the lack of knowledge of the engineers here. A simple change in timing would let traffic move at the speed limit and make the lights.
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Old 04-29-2018, 09:27 AM
 
6,049 posts, read 1,475,091 times
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Quote:
Originally Posted by Tek_Freek View Post
Those lights are probably on timers with no detection set up for oncoming cars. In Las Vegas I never see anything to adjust signals for varying traffic patterns. The lights seem to change on a single, timed pattern.

I have found that if I am at a red light on a main street and i drive 10 mph over the limit when I leave the intersection I will make all the lights ahead of me. In my opinion this shows the lack of knowledge of the engineers here. A simple change in timing would let traffic move at the speed limit and make the lights.
Have you considered that the goal MAY NOT have been to keep traffic flowing though? If they intentionally time lights so cars going the speed limit will get stuck at multiple red lights...well, that tells me, the goal is probably not to keep traffic flowing. It seems illogical, but they can time these lights however they desire.

I used to know a guy who thought they timed these lights with the intention of causing traffic, something about the longer people sit in traffic, the more fuel they are using, but Im not sure about that, for one, it would be way too obvious.
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Old 04-29-2018, 03:18 PM
 
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I worked with engineers for 22 years. I believe the people who time these lights are engineers.

I'll leave that laying there next to the non-existent trip plates on a Las Vegas street.
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Old 04-29-2018, 05:17 PM
 
938 posts, read 410,568 times
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Interesting a newer west coast city like LV would not have trip sensors. I guess that’s why the traffic is often so bad. Though I do know that older city centers often don’t have them as the lights had been installed a long time ago and traffic in downtown is constant especially where pedestrians and bicyclists also need to cross often, so trip sensors won’t make sense except at maybe early AM hours.
Though they make great sense in newer communities. And
LV, aside from downtown or the city center, is mostly a newer spread out place where there are lights with irregular traffic patterns with cross streets which doesn’t need a green light regularly since no one is there.

Though it’s true that some places do keep the speed down by keeping lights red unless it’s approached below a certain speed.

Last edited by citizensadvocate; 04-29-2018 at 05:27 PM..
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