What Percent of Idling Occurs at Red Lights?

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Idling at red lights significantly contributes to overall vehicle idling, but the percentage varies based on location, traffic patterns, and time of day. Observations indicate that traffic flow can be smoother during off-peak hours, while peak times often lead to increased stops and longer wait times at signals. The complexity of measuring idling at red lights arises from the need to consider various factors, such as the number of vehicles, traffic density, and synchronization of traffic lights. Estimates suggest that idling wastes billions of dollars annually in fuel, with figures ranging widely from $3 billion to $155 billion, highlighting the difficulty in obtaining accurate data. The introduction of vehicles with automatic engine stop-start systems aims to reduce idling waste, particularly in urban settings where traffic congestion is prevalent. Discussions also touch on the frustrations of delayed traffic flow at intersections and the potential for smarter traffic light systems to enhance efficiency.
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I want to know that how much idling occurs at redlights (in percent) out of the total idling done at various times and places?
 
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Depends on where you live/drive.
 
anubodh said:
I want to know that how much idling occurs at redlights (in percent) out of the total idling done at various times and places?

I guess write a personal log and find out?
 
Can you tell on an average like more than or less than x%?
 
anubodh said:
Can you tell on an average like more than or less than x%?
It is route-dependent, e.g., the length and number of lights, in conjunction with traffic density and scheduling of the lights.

I've driven the same route at different times of the day. In the early morning, I found that the lights were synchronized such that it was not necessary to stop or if I had to stop, it was short. Traveling about 1 hour later, I would have to stop frequently, and usually the traffic density was greater. The lights were not synchronized for smooth traffic flow.

One could quantify the problem by measuring the rate of traffic flow as a function of time, and how many cars must stop at a particular intersection. That would have to be done at each intersection on each route, or at selected intersections. The problem is complicated since cars may enter or leave the traffic flow at intermediate intersections where lights may or may not be present.
 
The actual question was to compare idling at red lights to idling for other situations (not what percent of the morning commute was spent idling).

That would be very hard to estimate. You'd have to actually observe the idling behavior of a lot of people and your results would vary substantially depending on the location/season/etc that you made your observations (people in Alaska are much, much more likely to leave their vehicle idling out in the parking lot while shopping/dining out/etc in the middle of the winter than people living in a warmer climate would, for example).
 
I'm usually idling behind someone who is driving with 2nd gear in a 50kph zone :<
 
BobG said:
The actual question was to compare idling at red lights to idling for other situations (not what percent of the morning commute was spent idling).

Where I live I have to drive through lights wherever I go. Where my Dad bought a country house I have to drive 30 kilometers to the first crossroads with lights. It is obvious that the answer to the original question is different in both places.
 
A bit off topic but there are already several vehicles on the market that stop the engine when the vehicle is not moving. Idling when the vehicle is stopped is a great waste of energy.

If each car in the
United States idles just 6 minutes per day, about 3 billion gallons of
fuel are wasted annually, costing drivers $10 billion.

http://www.transportation.anl.gov/pdfs/EE/642.PDF

The thing that really bugs me about red lights is the lag time. By that I meant that when the light turns green the first vehicle starts to move fairly quickly (or receive the wrath of a horn blower in vehicle number two).

On the other hand we all have noticed that by the time vehicle number 20 starts to move (that would be me) the light turns red again before I get to the intersection.

Just from my own observation I have timed a lag of from 20 to 30 seconds.

I like this authors point of view on traffic slowdowns on the freeways. In most cases there is no accident, so what the heck happened?

http://www.smartmotorist.com/traffic-and-safety-guideline/traffic-jams.html
 
  • #10
anubodh said:
I want to know that how much idling occurs at redlights (in percent) out of the total idling done at various times and places?
Depends if the gender, I find men spend a lot of time idling at red lights :roll eyes: To answer the second part of your question, especially after midnight in Amsterdam.
 
  • #11
Monique said:
Depends if the gender, I find men spend a lot of time idling at red lights :roll eyes: To answer the second part of your question, especially after midnight in Amsterdam.

Hold on!
If you have found this, how much time did you idle around those red lights? ;)
 
  • #12
Here in California, we usually idle on the interstate highways most of the time.

[Actually, I have an electric car. It doesn't idle.]
 
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  • #13
I like Serena said:
Hold on!

If you have found this, how much time did you idle around those red lights? ;)
All I needed to do was look out the window :biggrin:
 
  • #15
anubodh said:
At some sites it is written that idling wastes around 3 billion dollars in us but at this site
http://www.fieldtechnologies.com/us-drivers-waste-155-billion-dollars-a-year-idling-in-traffic/
It is written that 155 billion dollars are wasted.
So, can anyone tell how much is actually wasted (approx)

It is a difficult number to determine because the a number of factors in the equation are unknown. How many vehicles are at idle, for how long, and what size engine are always going to be an educated guess.

Several car builders are coming out with vehicles that stop the engine at idle.
One of the big problems was a need for a battery that could handle the extra load. This has now been accomplished with the new AGM battery.

Instead, they use a type of 12-volt battery called an absorbed glass mat (AGM) battery. The electrolyte is contained in thin woven glass mats rather than flooding the cells as in a typical "wet" battery. It also is pressurized for a greater power density.

AGM batteries' advantage over conventional 12-volt lead-acid batteries is that they recharge up to five times faster and can be deeply discharged with no damage. Those are essential characteristics for a battery that's being called on to start and restart a vehicle's engine scores of times a day.

http://www.edmunds.com/fuel-economy/engine-stop-start-systems-save-fuel-at-low-cost.html

Mercedes stop start system.
 
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  • #16
The thing that really bugs me about red lights is the lag time. By that I meant that when the light turns green the first vehicle starts to move fairly quickly (or receive the wrath of a horn blower in vehicle number two).

On the other hand we all have noticed that by the time vehicle number 20 starts to move (that would be me) the light turns red again before I get to the intersection.
I've been at a redlight in a line so long that the light turns green, then turns red, then turns green again before I actually get to move. I'm actually moving from that first green light. So to actually get through the intersection, it took probably 20 minutes. Something needs to be done about traffic. It almost makes you not want to bother leaving the house in your car. I hate driving mainly because of the people on the road being psychopaths, but also because of traffic. I won't go out some days because the reward of going out doesn't outweigh the grief of driving there and back.
 
  • #17
leroyjenkens said:
I've been at a redlight in a line so long that the light turns green, then turns red, then turns green again before I actually get to move. I'm actually moving from that first green light. So to actually get through the intersection, it took probably 20 minutes. Something needs to be done about traffic. It almost makes you not want to bother leaving the house in your car. I hate driving mainly because of the people on the road being psychopaths, but also because of traffic. I won't go out some days because the reward of going out doesn't outweigh the grief of driving there and back.

Yep with all of the technology in vehicles one would think that they could teach them to communicate a bit. When that first car stopped at a light starts to move car number 15 needs to know about it.

I wonder what the Google "drives itself" car would do?
 
  • #18
edward said:
When that first car stopped at a light starts to move car number 15 needs to know about it.
I don't quite understamd the problem there. In the UK the standard solution is to look out of the windows to see what the other traffic is doing :confused:

But maybe we tend to have smarter lights systems, if only because the average UK traffic density is a lot higher than the average in the US. IIRC there are only a couple of US states that are higher than the UK average over the whole country.

Lights at single intersections that are linked to camera systems rather than road sensors are quite common. If traffic is light and the lights on your road happen to be on red, they will have changed by the time you reach the intersection if no other traffic is there already. You might have to slow down from a 40 limit to 30 or 25 as you approach the intersection, but that wastes less time and fuel than having to stop for no good reason.

In urban areas there are often linked systems of lights over several miles of road, so if you stick to the speed limit you should only hit one red light driving through the entire system.
 
  • #19
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