NetLogo User Community Models
## WHAT IS IT?
HB-SOTL is a model of traffic moving in a city grid. It allows you to control traffic lights and global variables, such as the speed limit and the number of cars, and explore traffic dynamics. In our model, cars have a source and a destination, roads can have one or two directions, each of which can can have one or two lanes. We add new control methods, namely hb-sotl, hb-comm-sotl, QL-sotl, and LA-sotl.
From version 8.0 on, HB-SOTL is an extension of HB-COMM-SOTL (History-Based Self-Organizing Traffic Lights with Communication) by Pedro S. Rodriguez-Hernandez & Juan C. Burguillo-Rial.
HB-COMM-SOTL was an extension of Learning-SOTL (Self-Organizing Traffic Lights with Learning Algorithms) by Pedro S. Rodriguez-Hernandez & Juan C. Burguillo-Rial.
Learning-SOTL was an extension of HB-SOTL (History-Based Self-Organizing Traffic Lights) by Pedro S. Rodriguez-Hernandez & Juan C. Burguillo-Rial.
HB-SOTL versions 1.0 to 7.0 was an extension of SOTL (Self-Organizing Traffic Lights) by Carlos Gershenson. The HB-SOTL is documented at the publication: Juan C. Burguillo-Rial, Pedro S. Rodríguez-Hernández, Enrique Costa-Montenegro, Felipe Gil-Castiñeira. History-based Self-Organizing Traffic Lights. Journal of Computing and Informatics (CAI) 22, pp. 1001-1012. 2009. Available at: http://www.cai.sk/ojs/index.php/cai/article/viewFile/30/17
SOTL was extended from the model "Gridlock" by Uri Wilensky & Walter Stroup, which comes with NetLogo 2.0.0 (see more info at the bottom)
+ HB-SOTL is based upon version 1.0 of HB-COMM-SOTL
+ HB-COMM-SOTL was based upon version 7.2 of Learning-SOTL
+ Learning-SOTL was based upon version 7.0 of HB-SOTL
+ We are trying to test the effect of having devices to measure the cars which traverse the intersection in only a fraction of the traffic lights controllers
+ HB-SOTL's name stands for "history-based SOTL"
+ At every lights cycle, the intersection controller makes a decision based on the amount of cars which have traversed this intersection in the *previous* cycle, if it has this information. If not, it acts as the "marching" controllers.
0.00 2007-03-08 just removed torus? and four-dirs?
1.00 2007-04-30 added source/destination to cars. Modified the procedures
1.00 2009-05-22 cleaning of HB-SOTL 7.0
7.20 2009-11-20 added a slider for defining the number of states, and changed the sliders
1.00 2009-12-11 cleaning of Learning-SOTL 7.2
8.00 2010-09-15 cleaning of HB-COMM-SOTL 1.0
8.10 2010-11-11 now the car-meters information is used by hb-comm-sotl too.
## HOW TO USE IT
## QUICKSTART INSTRUCTIONS:
Run "Setup" before starting simulation. Then start and stop with "Go". Some parameters, such as grid-sizes and four-dirs? will be applied only after pressing "Setup".
Tip: you can "freeze" the display (on top of the "city" display) and/or switch off the plots to accelerate simulations.
For SOTL details, consult the paper "Self-Organizing Traffic Lights" http://uk.arxiv.org/abs/nlin.AO/0411066
"Setup"- Initializes simulation
"Re-run"- "soft" and quick "Setup" (just clears variables, doesn't change street topology)
"Reset-TL"- Turns phases of adaptive control methods ("sotl"'s and "cut-off") to zero, so that they need to adapt again (to check robustness)
"Go"- Start and stop simulation
"Step"- Run simulation just one time step
"Refresh Plots"- Clear all plots
-control- select control method for traffic lights (now, when changing methods during the same run, resetTL is automatically called. (If one was yellow, can cause problems...)
"grid-size-x"- number of vertical streets
"grid-size-y"- number of horizontal streets
"number"- initial number of cars for "Setup" and "Re-run", intended average number of circulating cars
%vertical- percentage of cars initially flowing in vertical roads, if starting at an intersection (%horizontal= 100-%vertical)
%origin-out- percentage of cars with origin outside the world
%destination-out- percentage of cars with destination outside the world
%bidirectional- percentage of bidirectional streets
%2-lane- percentage of streets with two lanes in the same direction
simulation-speed- regulates processing speed
speed-limit- maximum speed of cars
p- phase period for cyclic control methods ("marching", "optim", and "no-corr")
mingreen- minimum green phase for "sotl-phase" and "sotl-platoon" controls
keep-platoon- "omega" distance at which cars are checked from green light in "sotl-platoon" control
cut-platoon- "miu" cars approaching a green light at which platoons can be cut in "sotl-platoon" control
queue-cut- lambda queue length for "cut-off" control
tolerance- "theta" threshold for all "sotl" control methods
metatolerance- attempt of metaadaptive regime. Doesn't work, keep set to zero...
deadlock-limit- maximum time to decide that a car is suffering a deadlock
aggressiveness- scale factor for the time slots of the green cycles in "self-org-history"
hb-depth- number of previous cycles to be taken into account in "self-org-history"
parking-probability- probability of parking a car that reaches its destination and is not a commuter (commuters always park)
parking-time-min- minimum time a car is going to be parked
parking-time-max- maximum time a car is going to be parked (the actual parking time is a random variable uniformly distributed among this value and the previous)
%commuters- percentage of cars with a fixed home-place and work-place, which are going to switch origin and destination between those 2 places
excursion-probability- probability for a commuter to make an "excursion" to a place other than its work-place or its home-place
power?- makes traffic lights work
yellow?- include yellow phase (1 timestep) between green and red phases
crash?- monitor crashes at intersections
plots?- switches plotting (off increases simulation speed)
movie?- activates the recording of the simulation as a movie
over-length?- activates the control of cars running for a extra-long time (this should only happen if there is an error in the guidance procedure)
## CREDITS AND REFERENCES OF ORIGINAL "GRIDLOCK"
This activity and associated models and materials was created as part of the projects:
Copyright 2002 by Uri Wilensky & Walter Stroup. All rights reserved.
Permission to use, modify or redistribute this model is hereby granted, provided that both of the following requirements are followed:
To refer to this model in academic publications, please use: Wilensky, U. & Stroup, W. (2002). NetLogo HubNet Gridlock model. http://ccl.northwestern.edu/netlogo/models/HubNetGridlock. Center for Connected Learning and Computer-Based Modeling, Northwestern University, Evanston, IL.
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