- Escalator:
        <escalator_upstairs mu="1" sigma="0.0" />
        <escalator_downstairs mu="0.5" sigma="0.0" />

- Idle escalator
        <v0_idle_escalator_upstairs mu="1.5" sigma="0.0" />
        <v0_idle_escalator_downstairs mu="0.8" sigma="0.0" />

Todo: We need to introduce a new property to pedestrians. Some pedestrians
      walk in escalators and some stand. Therefore we should have for
      the first type
      v0 = v0 + escalator_upstairs; or
      v0 = v0 + escalator_downstairs;
      and for the second
      v0 = escalator_upstairs; or
      v0 = escalator_downstairs;