Transit Coding

Transit Data Elements Stored in Visum

The version file uses the following VISUM network objects to define Transit Service:

1. Nodes – network nodes
2. Links - in the case of Transit, links hold auto travel time information by time of day.
3. Stop Points – Physical transit stops, with no required attributes.
4. Stop Areas – There can be multiple stop points per stop area in VISUM. Stop Areas are the main Visum network object to hold stop attribution and detail.
5. Stops – Groups of stop areas. There can be multiple stop areas per stop in VISUM (stops and stop points allow for improved representation of the transit options available to users, but the model largely focuses on Stop Areas and therefore most coding energy should be put into properly representing stop areas and possibly any stop point detail that exists within a larger stop areas).
6. Lines – Transit lines, with no required attributes for the ABM (but does need to exist to code line routes, which are the key object that the ABM interfaces with). The available Transport Systems for transit lines are Bus, Bus Rapid Transit (BRT or express bus), Streetcar, Light Rail, and Commuter Rail (WES).
7. Line Routes – Transit routes within a named line (like the "Red Line" might have both an inbound and outbound route).
8. Time Profiles – Transit line link run times and stop dwell times.

The following sections describe each of the attributes that need to be defined by the user for each Transit data Element.

Transit Modes

Field	Description
a	Bus Rapid Transit
b	Bus
e	Streetcar
l	Light-rail
r	Commuter Rail (WES)

Stop Area Attributes

Identifying any stop as either a Transit Center or Mall (istc or tm) will establish the stop as higher quality (and ABC = large platform, transit center, enhanced shelter) which is seen as a better option by travelers in the model (different constants - see Stop Area Attributes under the calculated fields below). For Smaller MPOs without these types of major transit hubs, these can be left as zero.

Field	Description
istc	Set as 1 if the Stop Area is a Transit Center. All stops can be left zero in the case of smaller MPOs.
istm	Set as 1 if the Stop Area is a Transit Mall. All stops can be left zero in the case of smaller MPOs.

Line Route Attributes

Headways are coded in seconds

Field	Description
NT5	Headway for the EA (early AM) time period code should be switched to EA (from NT) and 5 removed
AM4	Headway for the AM (AM peak) time period code should remove 4 to make it universal to model implementation
MD6	Headway for the MD (midday off-peak) time period code should remove 6 to make it universal to model implementation
PM4	Headway for the PM (PM peak) time period code should remove 4 to make it universal to model implementation
EV5	Headway for the EV (evening) time period code should remove 5 to make it universal to model implementation

Link Attributes

Time in seconds. All of these are saved from a warm start assignment.

Field	Description
EA_TTC	Link Travel time for the EA (early AM) time period
AM_TTC	Link Travel time for the AM (AM peak) time period
MD_TTC	Link Travel time for the MD (midday offpeak) time period
PM_TTC	Link Travel time for the PM (PM peak) time period
EV_TTC	Link Travel time for the EV (evening) time period

Line Route Item Attributes

Currently all of these can be left as zero if the user doesn't want to establish these.

Field	Description
EMME_DWT	dwell time, per mile for local bus and per stop for other transit types. Should ensure that this input is desired in the final configuration, and if so, should remove EMME from the input name. It seems that this type of information could just be stored in Visum's dwell time attribute. In the current configuration, this can be left at zero and default values will be used.
EMME_TTFIndex	transit function code from Emme conversion for Metro's implementation. Should ensure that this input is desired in the final configuration, and if so, should remove EMME from the input name. In the current configuration, this can be left at zero and default values will be used.
EMME_DATA1	Represents travel speed for transit vehicles. In Metro they are just set to 0. Zero results in the default speed of 30mph being used. Note that most legs in the transit network use auto time * a transit factor, so this field is not used at all in those cases. Should ensure that this input is desired in the final configuration, and if so, a better name should be developed. In the current configuration, this can be left at zero and default values will be used.

Transit Fields Calculated by Code, Not User Input

The following are transit inputs that are calculated by a pre-processor from other inputs and not input by the user directly:

Node Attributes

Field	Description
brdco	boarding cost - Set to 231 seconds We should provide some description for how this is calculated and what the value(s) represent

Stop Area Attributes

Field	Description
Stop Service Type (4 binary inputs): isbrt isscr islrt iscrr	Each of these variables are defined as: isbrt - Highest-order service = Bus Rapid Transit (BRT) (mode 'a') isscr - Highest-order service = street car (mode 'e') islrt - Highest-order service = light rail (mode 'l') iscrr - Highest-order service = commercial rail (mode 'r')
sttyp	Stop type: ABC = large platform, transit center, enhanced shelter D = Basic shelter. Identified by BRT nodes and any transit stop with an off-peak headway of 15 minutes or better. E = All other stops
stcon	Stop type constant for transit stop: ABC = 0.1582 (peak) 0.1075 (off peak) D = 0.1582 (peak) 0.0756 (off peak). E = 0 (peak and off peak)
wtpf	Wait time perception factor at stop: ABC = 0.88 (peak) 0.86 (off peak) D = 0.93 (peak) 0.94 (off peak). E = 1.0 (peak and off peak)

Line Route Attributes

Field	Description
op_bushr	Hourly buses per stop in off-peak network (60/off-peak headway)

Time Profile Attributes

Field	Description
ivpf	Establishing the in-vehicle perception factor, 0.95 for BRT routes, else 1.0
DWELL_TIME	The code processes the DWELL_TIME variable from a mix of transit mode type, pre length, and whether the user has coded values for EMME_DWT
RUN_TIME	The code processes the RUN_TIME variable from a mix of EMME_TTFINDEX, EMME_DATA1, and the auto travel times along the network provided from a warm start run, which is then combined with DWELL_TIME above (DWELL_TIME is added to RUN_TIME)