Intersection (vs. Roundabout) - Revision history

Xklit17 at 22:53, 15 January 2014

2014-01-15T22:53:49Z

Xklit17 at 22:53, 15 January 2014

2014-01-15T22:53:29Z

Xklit17 at 22:52, 15 January 2014

2014-01-15T22:52:25Z

Xklit17: finalization

2014-01-15T22:34:50Z

finalization

Xklit17 at 21:39, 15 January 2014

2014-01-15T21:39:25Z

Xklit17 at 09:32, 14 January 2014

2014-01-14T09:32:52Z

Xklit17 at 09:31, 14 January 2014

2014-01-14T09:31:11Z

Xklit17: Created page with "= Intersection (vs. Roundabout) = == Problem definition == - a description of the situation you solve (i.e. the task) == Method == - the discussion of possible solution..."

2014-01-14T09:30:54Z

Created page with "= Intersection (vs. Roundabout) = == Problem definition == - a description of the situation you solve (i.e. the task) == Method == - the discussion of possible solution..."

New page

= Intersection (vs. Roundabout) =

== Problem definition ==

- a description of the situation you solve (i.e. the task)

== Method ==

- the discussion of possible solutions, the selection of method and tools for the solution, reasons for such choice (why the selected methods and tools are the best for the problem)

Detailed description of the method, including parameters, ranges, schemes, model limitations, etc. The description must be detailed enough that anybody could replicate the experiment event without your model source codes.

== Results ==

- list of results, their analysis, interpretation and evaluation.

== Conclusion ==

- how the problem was solved

== Citations ==

== Simulation ==

Model source code (xls, spm, nlogo, mdl, etc. file)

@@ Line 49: / Line 49: @@
 [[File:xklit17-Real-sim.png|200px|thumb|right]]
 . The simulation with real measured data is suitable and work in a similar way as the real intersection, except the limitations noted in previous chapter. As we can see the on the screen-shot from NetLogo after over 15 000 ticks the intersection is not jammed and the incoming and outgoing cars from each direction quite represents the reality.
 . If you set the green lights timings without a correlation with the frequency of incoming cars from respective directions, you can see that the intersection jams. If the frequency of incoming cars from each direction was changing rapidly in time, the light timings would have to be adjusted to mitigate the risk of jams.
 . If you kill the lights (dead-lights switch to ON position) you can see that the waiting time of cars from any direction is almost zero and it allows most cars to go through intersection almost without stopping. But I think it is a flaw of the model, because in real-life scenario with lights dead most of the drivers would slow down and some of them could panic which would lead to random stops and maybe even some accidents. Although the simulation propose that if the intersection was converted to a roundabout, it could be more effective (in terms of waiting time of cars). A specific and rigorous simulation would have to be performed to validate this theory.

@@ Line 47: / Line 47: @@
 = Results =
 . The simulation with real measured data is suitable and work in a similar way as the real intersection, except the limitations noted in previous chapter. As we can see the on the screen-shot from NetLogo after over 15 000 ticks the intersection is not jammed and the incoming and outgoing cars from each direction quite represents the reality.
 . If you set the green lights timings without a correlation with the frequency of incoming cars from respective directions, you can see that the intersection jams. If the frequency of incoming cars from each direction was changing rapidly in time, the light timings would have to be adjusted to mitigate the risk of jams.

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 The model itself is based on a model Traffic Intersection by U. Wilensky, but it was vastly extended to suit the simulation needs. But the basic settings and description can be found in the base model Traffic Intersection and also in model Info in the NetLogo file.
-Although the description and proposal was stating that I'd love to compare this intersection to a roundabout, I was unable to trustworthy simulate the behavior on a roundabout. But in the model there is a scenario that the intersection's lights are down and are all green at once. The cars behavior with lights off is exactly the same as if the lights were on, which is a highly unlikely behavior, because most of the drivers do slow down when they see a problem with lights - e.g. blinking yellow light.
+Although the description and proposal was stating that I'd love to compare this intersection to a roundabout, I was unable to trustworthy simulate the behavior on a roundabout. But in the model there is a scenario that the intersection's lights are down and are all green at once. The cars behavior with lights off is exactly the same as if the lights were on, which is a highly unlikely behavior, because most of the drivers do slow down when they see a problem with lights - e.g. blinking yellow light. Car can turn right (first sub-intersection of the intersection) or left at any sub-intersection, as is complaint with Czech driving laws.
 The lights are timed and synchronized in two directions (without priority) to east-west and north-south.

@@ Line 27: / Line 27: @@
 = Model =
-Detailed description of the method, including parameters, ranges, schemes, model limitations, etc. The description must be detailed enough that anybody could replicate the experiment event without your model source codes.
+[[File:Xklit17-scheme.png|200px|thumb|right]]
-[[File:Example.jpg]]
+The intersection was simplified to allow easier modeling in NetLogo. The limitations of the model are written in following chapter. The NetLogo world size was set to {{-15,..,15},{-15,..,15}} and in the middle of the model is the intersection. Cars are entering from 4 sides and can exit at any side. All roads were modeled as dual ways as it is in reality, but the cars are unable to change lanes.
 == Limitations ==
@@ Line 39: / Line 47: @@
 = Results =
+. The simulation with real measured data is suitable and work in a similar way as the real intersection, except the limitations noted in previous chapter. As we can see the on the screen-shot from NetLogo after over 15 000 ticks the intersection is not jammed and the incoming and outgoing cars from each direction quite represents the reality.
- - list of results, their analysis, interpretation and evaluation.
+. If you set the green lights timings without a correlation with the frequency of incoming cars from respective directions, you can see that the intersection jams. If the frequency of incoming cars from each direction was changing rapidly in time, the light timings would have to be adjusted to mitigate the risk of jams.
+. If you kill the lights (dead-lights switch to ON position) you can see that the waiting time of cars from any direction is almost zero and it allows most cars to go through intersection almost without stopping. But I think it is a flaw of the model, because in real-life scenario with lights dead most of the drivers would slow down and some of them could panic which would lead to random stops and maybe even some accidents. Although the simulation propose that if the intersection was converted to a roundabout, it could be more effective (in terms of waiting time of cars). A specific and rigorous simulation would have to be performed to validate this theory.
 = Conclusion =
-- how the problem was solved
+The problem was to simulate and indicate if it would be better to turn this intersection to a roundabout. The model suggests that the roundabout could be more effective, but the drivers behavior was not simulated properly so it would require more detailed and more complex study. This this simulation vastly extends the current models in NetLogo because it added turning, exiting at different locations, dualways and few other ideas.
 = Citations =
+Wilensky, U. (1998). NetLogo Traffic Intersection model. http://ccl.northwestern.edu/netlogo/models/TrafficIntersection. Center for Connected Learning and Computer-Based Modeling, Northwestern Institute on Complex Systems, Northwestern University, Evanston, IL.
 = Code =
+Model source code [[File:xklit17.nlogo]]

← Older revision		Revision as of 09:31, 14 January 2014
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−	~~= Intersection (vs. Roundabout) =~~
−
	== Problem definition ==		== Problem definition ==

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 = Problem definition =
- - a description of the situation you solve (i.e. the task)
+During the last year almost every day I go around an intersection at Střelnická / Třebenická which has a really unique shape which reminds me of a Roundabout. I'd like to try to simulate the Intersection as an agent based simulation. There are 4 exits from the road:
 = Method =
+The model requires cars entering at different locations, speeds, exiting at different exits and being autonomous in the defined space and environment. The modeling tool should be able to take in account all these facts, so a agent based simulation seems like a clear choice. The other choice could be SimProcess with defined throughputs of each sub-intersection et cetera, but NetLogo is more suited for this kind of modeling and is way more intuitive and the model is almost self-explanatory.
 = Model =
 Detailed description of the method, including parameters, ranges, schemes, model limitations, etc. The description must be detailed enough that anybody could replicate the experiment event without your model source codes.
 = Results =

@@ Line 1: / Line 1: @@
-== Problem definition ==
+= Introduction =
   - a description of the situation you solve (i.e. the task)
-== Method ==
+= Method =
 - the discussion of possible solutions, the selection of method and tools for the solution, reasons for such choice (why the selected methods and tools are the best for the problem)
 Detailed description of the method, including parameters, ranges, schemes, model limitations, etc. The description must be detailed enough that anybody could replicate the experiment event without your model source codes.
-== Results ==
+= Results =
   - list of results, their analysis, interpretation and evaluation.
-== Conclusion ==
+= Conclusion =
 - how the problem was solved
-== Citations ==
+= Citations =
-== Simulation ==
+= Code =
 Model source code (xls, spm, nlogo, mdl, etc. file)