Enabling Private Traffic Route Choice

What is Route Choice?

A person who wants to travel from one location to another decides the route to be taken before embarking on the trip. This process of selecting the route between the origin and destination (OD) from a set of alternatives is known as route choice. The set of alternative routes between an OD pair is known as the path-set for that OD. Path-sets are a set of paths that are available for any given origin-destination pair.

##Pathsets As it is fairly common for multiple agents to have the same origin and destination, the path-set for such agents will be the same. In order to avoid computing the same path-set for multiple agents, the path-set for all the trips in the simulation is pre-computed and stored in the database. For smaller sized networks, it may even be possible to pre-compute and store the path-set for all possible OD pairs. Path-set generation is explained here

##Is Enabling Route Choice Mandatory? No!
SimMobilityST has the capability to compute shortest paths (distance based) on the fly. When the route choice is left disabled, all agents compute the shortest paths from their respective origins to their destinations. To ensure that the route choice is disabled, confirm that enabled fields mentioned in step 4 of the next section are set to false

Note: However, if public transit is enabled, enabling the route choice for public transit is mandatory

Enabling Private Traffic Route Choice

1. In the short-term specific configuration file, provide the location of the path-set configuration file
   <path-set-config-file value = "private/pathset_config.xml"/>

2. Add the following additional mappings in the proc_map being used.

   Network Component	Mapping
   ERP Gantry Zone	<mapping name= "erp_gantry_zone" procedure="<procedure_name_for_gantry_zones>"/>
   ERP Section	<mapping name= "erp_section" procedure="<procedure_name_for_erp_section>"/>
   ERP Surcharge	<mapping name= "erp_surcharge" procedure="<procedure_name_for_erp_surcharge>"/>
   Path-set	<mapping name= "pvt_pathset" procedure="<procedure_name_for_pvt-pathset>"/>

3. In the model_scripts tag, ensure that the path attribute points to the folder containing the lua models and that the format is set to lua. Also ensure the script tag specifies the file names for the logit and pvtrc models. A sample configuration is shown below

   <model_scripts path="scripts/lua/mid/behavior-models/" format="lua">
      <script name="logit" file="logit.lua"/> <!--The main logit code for multinomial and nested logit models-->
      <script name="pvtrc" file="pvtrc.lua"/> <!--private traffic route choice-->		
   </model_scripts>

4. In the path-set configuration file specified in step 1, set the enabled field in the pathset and private_pathset field to true. Also ensure that the mode in private_pathset is set to normal as shown below.
   <pathset enabled = "true">
<private_pathset enabled = "true" mode = "normal">

##Enabling Public Transit Route Choice

1. In the short-term specific configuration file, ensure that public transit is enabled as shown below
   <public_transit enabled="true"/>

2. Ensure that the location of the path-set configuration file is set correctly.
   <path-set-config-file value = "private/pathset_config.xml"/>

3. Add the following additional mappings in the proc_map being used.

   Network Component	Mapping
   PT Edges	<mapping name= "pt_edges" procedure="<procedure_name_for_pt_edges>"/>
   PT Vertices	<mapping name= "pt_vertices" procedure="<procedure_name_for_pt_vertices>"/>
   Rail Transit Edges	<mapping name= "rail_transit_edges" procedure="<procedure_name_for_rail_edges>"/>
   PT Path-set	<mapping name= "pt_pathset" procedure="<procedure_name_for_pt-pathset>"/>

4. In the model_scripts tag, ensure that the path attribute points to the folder containing the lua models and that the format is set to lua. Also ensure the script tag specifies the file names for the logit and ptrc models. A sample configuration is shown below

   <model_scripts path="scripts/lua/mid/behavior-models/" format="lua">
      <script name="logit" file="logit.lua"/> <!--The main logit code for multinomial and nested logit models-->
      <script name="ptrc" file="ptrc.lua"/> <!--public transit route choice-->
   </model_scripts>

5. In the path-set configuration file specified in step 1, set the enabled field in the pathset and public_pathset field to true. Also ensure that the mode in public_pathset is set to normal as shown below.
   <pathset enabled = "true">
<public_pathset enabled = "true" mode = "normal">