faq 44040198

How to increase the demand by (10%, 20%, 50%, ...) without changing the plans file?

by Kai Nagel on 2016-02-01 11:37:55

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(proxied for sehassan2007 at yahoo dot com)

 

Dear MATSim user

If I want to change the  demand for example: increasing the demand by (10%, 20 % ,50%) without changing in  plan file.

one possible way is to consider that the plan  file represent (10%, 20 %, 50%) of the total population and re scale the network by Flow Capacity Factor and storage capacity factor

Flow Capacity Factor and storage capacity factor will be:

0.1+0.3

0.2+0.6

0.5+1.0     I don't know if storage capacity factor can be greater than 1.0?

My question is the data obtained from link statistic(flow and Travel Time) have to multiply by 10, 20, 50. or not?

and what other changes I have to make in order to re scale the network in case  I have car +bus share the same road space.

and there are another way to increase the network demand to increase the congestion of the network?

Thank you in advanced 

Seham

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Comments: 1

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Re: How to increase the demand by (10%, 20%, 50%, ...) without changing the plans file?

by Kai Nagel on 2016-02-01 11:55:51

(1) Right, reducing/increasing the flow capacity factor will indeed do the trick.  I am not sure if I get your numbers the way you mean them; I would say

• demand increase by 10% = multiply demand by 1.1 = divide flow capacity by 1.1 = flow capacity factory = 1/1.1 = 0.91
• Etc.

If you have already started from a sample, adapt accordingly.

(2) I would expect that storage capacity factor > 1 is possible.  For the purposes of the traffic flow dynamics, it is the same as a larger number of lanes, and there is no limit to that.  Clearly, bugs may prevent this from working correctly, as usual.

(3) We typically use storage factor 0.03 for flow factor 0.01, and storage factor 1 for flow factor 1.  That is, for reduced flow factor we reduce the storage factor less than proportionally.  This has to do with the "grainedness" of the vehicles and the fluctuations this causes.  There is a paragraph about this somewhere but more systematic work would be good.

(4) Buses and cars on the same road space.  Good question.  You can imagine that a flow capacity factor of 0.1 means that every vehicle consumes 10 times more flow units than normal.  The same is true for pt vehicles. – Clearly, this is a problem in most cases, since the number of buses will not be reduced in the same way as the number of vehicles is typically reduced.  One possibility would be to reduce the "passenger car equivalents" in the pt vehicles file accordingly.  Unfortunately, this now means changing a file, which you wanted to avoid.  I am afraid that there currently is no other solution.

(5) Quite general, the compensation for the sampling (i.e. flow factor different from one) is not very good in matsim; this should be cleaned up.  See    Probably does not have high priority, since it would involve a large number of conventions to be clarified beforehand (like how shall we deal with buses that are entered as PCE=1 in the vehicles file as is the case in most situations).