The transit time functions, used to compute the travel times
individually for each segment of each transit line, used to allow
only for two parameters, the segment length (`length`

) and the corresponding
auto travel time (`timau`

). While these two parameters were adequate for
most standard applications, in applications where the exact segment
times were given on a segment by segment basis, this could only be
implemented by using a multitude of different transit time functions,
each corresponding to one specific speed.

Starting with release 3.0, more parameters can now be specified in transit time functions. The following list gives the complete set of parameters that may be used for transit time functions:

Keyword: | Parameter definition: |

`length` | Distance of corresponding link (in units of length) |

`speed` | Default speed of the transit line (in units of length/hr) |

`timau` | Auto time for the corresponding link (in minutes). This parameter is only defined for scenarios in which an auto assignment has already been performed. |

`ul1,ul2,ul3` | Link user data items 1, 2 and 3 |

`ut1,ut2,ut3` | Transit line user data items 1, 2 and 3 |

`veh` | Vehicle type of the transit line |