[sumo-user] Re: SUMO Question

[Christian <ro...@zp...>]

On Wed,  1 Dec 2004 09:55:57 +0100
wal...@eg... wrote:

> Dear Mr. Christian,
>=20
>   I'm using SUMO in my reasearch simulations in Computer Science. But I h=
ave=20
> some few Questions:

Hi Walaa,

since I don't take part in the SUMO developement any longer, please send=20
your future questions to the sumo-user mailing list. Subscribe here:
http://sourceforge.net/mail/?group_id=3D45607

> If I have a network description file that describes each edge by its free=
 flow=20
> speed, maximum capacity, jam density.
>=20
> How can I set such properties to an edge in the edges.xml file i.e. :
>=20
> 1- Can the speed attribute in the edges.xml (which is the max "allowed" s=
peed)=20
> represent the free flow speed? If not how can I introduce the free flow s=
peed=20
> to SUMO?

First, in SUMO the edges have a maximum speed and the vehicles have a=20
maximum speed too. Therefore the free flow speed of a single vehicle=20
is the minimum of the two maximum speeds.=20

Second, the last step of the velocity calculation is dawdling. The=20
desired speed, which is <=3D the free flow speed, is randomly reduced=20
by "eps a", where eps is the dawdle-parameter out of [0,1] and a is=20
the acceleration-parameter of the vehicle type. If eps !=3D 0, then a=20
measured average free flow speed will be less than the calculated=20
free flow speed.

=20
> 2- How can I express the edge's max capacity and jam density in SUMO?

The jam density in given by the vehicle length. In a jam the vehicles=20
will stand "bumper at bumper". This will take some time if eps !=3D 0.=20
So the jam density in [veh/km] is 1000/vehicle_length_in_meter.

With capacity you mean flow, right? You can't express the maximum flow=20
directly. The flow depends on the vehicle type parameters.

Best regards
  Christian
--
Christian R=F6ssel   <chr...@gm...>