I need to evaluate the impact of the introduction of adaptive control at an intersection on the accident. I suppose it's done with a simulation in PTV vissim. Please tell me the literature, which describes how to predict the accident with the help of the simulation model in PTV vissim. Thanks in advance.
Dear Sergei,
It's possible to use vissim models to evaluate road safety. To do that, there is a free software developed by the Federal Highway Administration (FHA-USA) known as Surrogate Safety Assessment Model (SSAM). This software identifies conflicts between vehicles and determines surrogate safety measures based on Traffic conflicts theory. Once the Vissim model is calibrated, its necessary to generate a .trj file (in Vissim) and that .trj file most be used in SSAM. Given that Vissim and SSAM do not simulate crashes, a FHA's report about SSAM show a relationship between conflicts/hour and crashes/year (R2=0.4) (please see attached file). Check out the link below for full details about SSAM.
I hope this can help you.
Lenin B.
http://www.fhwa.dot.gov/publications/research/safety/08050/
Ms. Fatemeh,
Please check the link below. You'll find some SSAM's features and a "Download registration" link. Then you should complete a form and in a few days you'll receive an email with the software download link and another two links with an user manual and release notes.
Important: current version (2.1.6) works better in Windows XP. I had problems with Windows 7 due to screen resolution conflicts so I moved to XP.
Have a nice day.
Lenin
http://www.fhwa.dot.gov/research/tfhrc/projects/projectsite/safety/ssam/index.cfm
Hi all,
my opinion is a bit different: it is very difficult to use the common microscopic traffic flow simulators to predict accidents. What was originally done in SSAM was to use trajectory data to compare different intersection layouts. This may make sense because the intersection geometry indeed determines how many conflict points or potential conflicts points, if a driver did not follow the "planned" trajectory, are present in a certain layout.
But I would never state a robust relationship to real accident rates, not in the SSAM study setup and even less in other contexts.Vissim's driver behavior model does not include any accident related parts. There are stochastic elements, true, and there is even the "temporary lack of atention" feature, but these are included to model capacity, not road safety.
To assess safety, e.g. for a new ITS system, sometimes the distributions of accelerations or time-to-collision or even more elaborate figures are used. This might give an indication whether a system increases or decreases the number of safety critical situations, but this indication is weak only because the driving model is designed safe and does not include - I repeat - any causality that might lead to accidents.
I know that this sounds a bit negative :-)
But this area is really very controversial, and before you simply use SSAM, make sure that you know the context.
Best regards, Peter
Basically you are looking to get the Crash Modification Factor after implementing a certain treatment (i.e., adaptive control). For this please check my paper: https://www.researchgate.net/publication/263284661_Integrated_traffic_conflict_model_for_estimating_crash_modification_factors
The traffic conflict approach has been criticized, for lacking a formal link to observed and verified crashes, a difficulty that this paper attempts to resolve by presenting and investigating an alternative approach for estimating CMFs using simulated conflicts that are linked formally to observed crashes.
Article Integrated traffic conflict model for estimating crash modif...
Hi Chetan Doddamani,
This might be late but check out the link below.
I hope it helps.
http://liu.diva-portal.org/smash/record.jsf?pid=diva2:921716
Hi, this article may be helpful.too
Validation of the Surrogate Safety Assessment Model for Assessment of Intersection Safety - DOI: 10.3141/2432-01 - Transportation Research Record.
Is there any software to get .trj data for free? Because it will Charge a lot of money to buy Vissim. (May I use student version for my academic resarch?)
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