Transit Network Development

Input files specifying transit attributes are located in the Inputs\Transit folder. See the Transit Inputs page for a data dictionary and the required and optional transit line attributes.

Mode definition

The selected mode and operator should be consistent with the definitions laid out in the Transit Inputs.

Representing transit priority

SERPM 8 utilizes congested highway travel times to calculate the transit travel times, i.e. at the link-level, transit service operates at the same speed as private autos on the roadway. Note that transit routes also include a dwell time, therefore the effective speed is lower than private autos along a route. If there are special transit facilities (e.g. queue-jump lanes and TSP, dedicated right of way, etc.), the modeler has three options when representing special transit facilities.

1. Create new, transit-specific, links in the highway network.
2. Set the transit travel times on existing highway links.
3. Code travel time as part of the transit line definition

Transit-specific links

When coding transit-specific links, care must be taken to connect the stop nodes to the roadway network, otherwise paths with transfers between transit modes (e.g. local bus to Tri-Rail) or PnR / KnR access will not be created. The links connecting transit-specific links to general roadway links are FTC2=59.

The following attributes must be set for transit-specific links:

• FTC2 = 49 or 69
• TMODE = transit mode number utilizing link (must be > 10)
• TTIME = transit travel time
• TSPEED and TDIST = used to create transit travel time (and will override TTIME settings)

Note that transit-specific links with TMODE = 11,21,22,23,24 (TriRail, LRT, BRT, Metromover) will NOT be available as walk connections.

Transit travel time on general highway links

The primary consideration when coding transit on general highway links is that ALL transit modes utilizing the link will use the specified transit time. This is a concern if a new service, say LRT, is added to a roadway with local bus service but the local buses are not able to use the same ROW as the LRT.

The following attributes must be set for links with transit-specific travel times:

• TMODE = transit mode number utilizing link (see modes identifiers here)
• TSPEED and TDIST = used to create transit travel time (and will override TTIME settings)
• TTIME = transit travel time (only used is TSPEED is 0)

Travel time in the transit line definition

The Cube Public Transit line definition supports the following attributes:

• RUNTIME / RT: End to end running time.
• NNTIME: Travel time between key stop locations.
• TIMEFAC: Factor applied to travel time of all links.

The modeler should consult Cube's help documentation for more information on using these settings.

Defining auto access to transit stops

To enable a transit stop to have auto access and egress connections by either PnR or KnR, the following attributes must be set in the Highway Node:

• ACTIVEFLAG: set to 1
• STATIONNUMBER:
• STATIONDESC:
• PARKINGSPACES: if the stop is primarily a KnR, this can be set to a small number (e.g. 1),
• SERVICEMILES: this indicates the maximum distance between the TAZ and transit stop

Optionally, the modeler may also set:

• PARKINGCOSTAM: representing the lot parking fee
• TERMTIMEPNR: representing the time to move from the parking lot to the transit stop

It is also useful to code the descriptive