faq 302383125

Unreasonably high share for taxis with high price

by Jishnu Narayan on 2018-07-13 14:28:46

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Hello all,

I am working on the Scenario of Amsterdam with 160000 agents and modes of Car, Walk, Bike, Pt, and Taxi. I am interested in the market share of taxis and pt for varying fare of taxis. I've started with taxis being 10 times more costly as pt (which is close to reality in Amsterdam). But in spite of such a high price, the share of taxis is unreasonably high (close to 60%). I use the "monetaryDistanceRate" in the modeParams to model the fares. In order to further check the effect of the parameter, I tested with a really large value of "monetaryDistanceRate" (100000000 times that of pt), but still the mode share is unaffected. I suppose the value "monetaryDistanceRate" is not used in computing the utility of the plan. Could there be any other reason for this unusual behavior? Also, how can the fares of modes be efficiently represented in the model if not the "monetaryDistanceRate" parameter. Any help would be deeply appreciated.

The modeParams for pt and taxi used are given below (taxis are 10 times expensive as pt).

<parameterset type="modeParams" > <!-- [utils] alternative-specific constant.  no guarantee that this is used anywhere. default=0 to be backwards compatible for the time being --> <param name="constant" value="0.0"/> <!-- [utils/m] utility of walking per m, normally negative.  this is on top of the time (dis)utility. --> <param name="marginalUtilityOfDistance_util_m" value="0.0"/> <!-- [utils/hr] additional marginal utility of traveling.  normally negative.  this comes on top of the opportunity cost of time --> <param name="marginalUtilityOfTraveling_util_hr" value="-6.0"/> <param name="mode" value="pt"/> <!-- [unit_of_money/m] conversion of distance into money. Normally negative. --> <param name="monetaryDistanceRate" value="0.000154"/> </parameterset>

<parameterset type="modeParams" > <!-- [utils] alternative-specific constant.  no guarantee that this is used anywhere. default=0 to be backwards compatible for the time being --> <param name="constant" value="0.0"/> <!-- [utils/m] utility of walking per m, normally negative.  this is on top of the time (dis)utility. --> <param name="marginalUtilityOfDistance_util_m" value="0.0"/> <!-- [utils/hr] additional marginal utility of traveling.  normally negative.  this comes on top of the opportunity cost of time --> <param name="marginalUtilityOfTraveling_util_hr" value="-6.0"/> <param name="mode" value="taxi"/> <!-- [unit_of_money/m] conversion of distance into money. Normally negative. --> <param name="monetaryDistanceRate" value="0.00154"/> </parameterset>

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Comments: 1

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Re: Unreasonably high share for taxis with high price

by Joschka Bischoff on 2018-07-13 15:16:24

Hi Jishnu,

until Matsim 0.10., setting a monetary distance mode for taxi is not supported, as there is no distance set in the route of the leg in the plan. This is mainly, because the route is calculated once the passenger departs and thus not clearly defined in the plan.

Instead, you can use a specified taxi fare handler with a dedicated config group that supports additional features, such as subscriptions and flag fall fares.

See here:

https://github.com/matsim-org/matsim/blob/0.10.x/contribs/av/src/main/java/org/matsim/contrib/av/robotaxi/run/RunRobotaxiExample.java

and here for the fare handler

https://github.com/matsim-org/matsim/blob/0.10.x/contribs/av/src/main/java/org/matsim/contrib/av/robotaxi/scoring/TaxiFareHandler.java

A set of example files can be found at

https://github.com/matsim-org/matsim/tree/0.10.x/contribs/av/src/main/resources/cottbus_robotaxi

We are changing this for Matsim 0.11, so Monetary distance route may also be used, based on an estimate.

Bests,

Joschka