Hello, 1) the lane changing model in SUMO is general enough to encompass ramp behavior. See "Lane Changing Model in SUMO", http://sumo.dlr.de/2014/Proceeding_SUMO2014_15+16May2014_Berlin-Adlershof.pdf for details. There a still some known issues at on-ramps because the (default) car-following model is overly safety-conscious. 2) SUMO uses a 1.5D model. Each lane is a discrete entity, vehicle positions on a lane are 1D. For visualization on a 2D lane geometry simple geometric transformations are done. 3) Yes. See http://sumo.dlr.de/wiki/TraCI. Python bindings are included with SUMO. 4) Hm. There are some high level overview publications but nothing all-encompassing at medium level. See http://sumo.dlr.de/wiki/Publications (Another recent low-level publication is "Road Intersection Model in SUMO" http://sumo.dlr.de/2013/SUMO2013_15-17May%202013_Berlin-Adlershof.pdf.
regards, Jakob 2014-12-20 23:39 GMT+01:00 Angus Hollands <[email protected]>: > Hi everyone, > > This is a little on the lengthy side of things, I hope you don't mind. > > I'm currently working on a traffic simulation for a commercial project. The > validity of the simulation is important, but in itself no metrics are > required; it serves only as a visual aid to challenge the product's users > when they complete various tasks. > > Prior to this moment, I have been working with a multi-lane simulation > which did not include any off/on ramps or more complicated traffic systems. > At this point, I moved to a "node based" model, which analyses geometry of > a 3D mesh (using some helper information) to produce a graph of connected > nodes. > > It has only been when writing the simulation for this graph that I realise > how much more complicated the simulation must become. The list below > indicates my new challenges: > > 1. Ramp merges affect the vehicles in the lane as well as those which > are about to merge. Unlike lane merging, which is optional and only > performed if the impact is minimal, vehicles on ramps prefer to maintain > velocity, and vehicles behind them in the new lane will slow down > somewhat. > This changes the purist IDM model. > 2. Routes require some level of planning in order to determine how far > to the nearest vehicle. Whenever the vehicle ahead is on a separate lane > (in the case of an on ramp, or a "decision" node where one lane can go > either of two directions), we must investigate this and recall the path > we > took, so that our behavior corresponds with the vehicle we're > following. We > cannot consider artificially congesting routes unless we force a > percentage > of vehicles to follow those routes. > 3. Road representation. I'm using polygons, but this creates its own > challenge - using portals as midpoints along polygon edges for smooth > lane > changes and ramp exit/entrance. Long story short, being able to work out > which vehicle is ahead of which is difficult when you're working with > such > flexible implementations. > > These are not the only problems I have or will continue to face, but I > notice that SUMO is a mature (13 years?) simulation framework and I hoped > to ask a few higher order questions. > > > 1. How does SUMO handle ramps? Both in terms of the linear acceleration > models of the vehicles involved and in the planning stage. > 2. How does SUMO represent the vehicle in terms of its position on the > road, and then convert to/from 2D cartesian coordinates? > 3. Would it be possible to ask SUMO (with the Python interface) to spawn > vehicles in specific positions at a user-defined interval, perhaps > irregularly? I suspect that given other requirements of the simulation, > I'd > need to write my own Python bindings for certain things. > 4. Is there any documentation on the overarching structure of the > simulation design? > > > I'm sure that I will have more questions, but any help at this stage would > be great, > kind regards, > Angus Hollands. > > ------------------------------------------------------------------------------ > Download BIRT iHub F-Type - The Free Enterprise-Grade BIRT Server > from Actuate! Instantly Supercharge Your Business Reports and Dashboards > with Interactivity, Sharing, Native Excel Exports, App Integration & more > Get technology previously reserved for billion-dollar corporations, FREE > > http://pubads.g.doubleclick.net/gampad/clk?id=164703151&iu=/4140/ostg.clktrk > _______________________________________________ > sumo-user mailing list > [email protected] > https://lists.sourceforge.net/lists/listinfo/sumo-user > ------------------------------------------------------------------------------ Download BIRT iHub F-Type - The Free Enterprise-Grade BIRT Server from Actuate! Instantly Supercharge Your Business Reports and Dashboards with Interactivity, Sharing, Native Excel Exports, App Integration & more Get technology previously reserved for billion-dollar corporations, FREE http://pubads.g.doubleclick.net/gampad/clk?id=164703151&iu=/4140/ostg.clktrk _______________________________________________ sumo-user mailing list [email protected] https://lists.sourceforge.net/lists/listinfo/sumo-user
