Scenario File Parameters

All top-level parameters are first read by POLARIS through the scenario_abm.json file (or simple the scenario file). Parameters in this file include high-level flags to turn on and off large features, and also filenames to point to additional parameter files that are specific to enable or control a feature.

Top Level Parameters

These are the top level parameters that are available in the scenario.json file which is the first argument to the POLARIS exectuable.

These parameters are read in in the Scenario_Methods.h header file.

Category	Parameter Name	Description	Default	Data Type
ABM Controls	read_trip_factors	Controls the percentage of trips that need to be read in from the demand database by trip type (External, TNC, or Fixed)	nan	nan
	activity_start_time_model_file_name	initialize start time model with file path in Integrated_Model	start_time_duration_data_new.txt	string
	mode_choice_model_file	pass parameter into mode_choice_option_type::static_initialize in Integrated_Model	0	string
	activity_generation_model_file	activity generation activity rates by person type in json format	0	string
	destination_choice_model_file	pass parameter into destination_choice_option_type::static_initialize in Integrated_Model	0	string
	telecommute_choice_model_file	pass parameter into telecommute_chooser_type::static_initialize in Integrated_Model	0	string
	transit_pass_choice_model_file	pass parameter into ecommerce_chooser_type::static_initialize in Integrated_Model	0	string
	escooter_use_level_choice_model_file	Escooter use related model parameters	0	string
	ecommerce_choice_model_file	pass parameter into ecommerce_chooser_type::static_initialize in Integrated_Model	0	string
	cav_wtp_model_file	pass parameter into vehicle_technology_chooser_type::static_initialize in Integrated_Model	0	string
	vehicle_reduction_model_file	Model to lower HH vehicle ownership using Menon et al.'s probit model. Used primarily by UT only.	nan	nan
	use_on_demand_delivery	Controls turning on and off ODD demand	FALSE	bool
	delivery_choice_model_file	On-demand delivery related parameters for estimating demand only	nan	nan
	utility_based_choice	boolean flag indicating that location choice should be based on maximum individual utility with consistently seeded random utility	FALSE	bool
Capacity Adjustments	capacity_adjustment_highway	if _link_type is EXPRESSWAY or FREEWAY, then save parameter as capacity_adjustment_factor in Link_Implementation	1	double
	capacity_adjustment_arterial	if _link_type is ARTERIAL, then save parameter as capacity_adjustment_factor in Link_Implementation	1	double
EV Controls	use_retail_electricity_rates	Flag to set whether retail or wholesale rates are used for electricity pricing	FALSE	bool
	Public_Charger_Access_For_Fleets	Flag that allows shared vehicles to charge at public EVCS	FALSE	bool
	Private_Charger_Access_For_PVs	Flag that allows personal vehicles to charge at private EVCS	FALSE	bool
EVCS Generator Controls	GENERATE_EVCS	Flag to enable heuristic EVCS generation	FALSE	bool
	evcs_generator_file_name	File that holds parameters related to heuristic EVCS generation	nan	string
General simulation controls	model_directory	The top-level directory in which the simulation is running	Directory in which the scenario.json resides	Path
	input_directory	The directory containing the inputs for the current simulation (i.e. previous iteration)	model_directory	Path
	starting_time_hh_mm	The first time step to consider within the simulation	0	int
	ending_time_hh_mm	The last time step to consider within the simulation	172800	int
	simulation_interval_length_in_second	How long (in seconds) is each step through the simulation	6	int
	use_link_based_routing	true = restrict routing to activity locations to link+dir, false = route to an activity location on a link using either direction	FALSE	bool
	seed	seed = abs( sin( iseed( ) + _internal_id + 1 ) ) in Intersection_Implementation	0	unsigned long
	skim_seed	Parameter to change initial seed for location sampling for car skim generation	0	unsigned long
	zone_sample_fraction	Parameter to adjust size of destination choice set per person and activity. Note this is a fraction of total zones and the actual number of zones used will be calculated as max(1.0, number_of_zones * zone_sample_fraction).	1	float
	database_name	the prefix used in all database filenames, i.e. **Chicago**-Supply.sqlite	0	string
	input_directory	Directory in which input databases can be found, generally a previous iteration or a backup folder; if a relative path is provided it will be interpreted relative to the model_directory	nan	string
	num_simulation_intervals_per_assignment_interval	parameter * simulation_interval_length = assignment_interval_length	50	int
	early_exit	Causes the simulation to exit the simulation after the specified operation, valid options are: {after_pop_synth, after_loc_choice, after_activity_gen}	nan	nan
Network simulation controls	merging_mode	Used to determine intersection supply allocation from multiple incoming flows, one of {0: DRIVING_RULE, 1: PROPORTION_TO_DEMAND, 2: PROPORTION_TO_LINK, 3: PROPORTION_TO_LANE, 4: PRIORITY_BASED}	PROPORTION_TO_DEMAND	int
	node_control_flag	when set, indicates that read_intersection_control_data is available, else intersection_type = NO_CONTROL and control_plan is allocated and initialized	0	int
	ramp_metering_flag	if true, then read from ramp_metering_data	FALSE	bool
	input_result_database_name	required for time-dependent routing	0	string
	jam_density_constraints_enforced	if true, then enforce jam density constraints when computing intersection flow	TRUE	bool
	maximum_flow_rate_constraints_enforced	if true, then whether to enforce maximum flow rate constraints when computing intersection flow	TRUE	bool
	pretrip_informed_market_share	_has_pretrip_information = (Uniform_RNG.Next_Rand < parameter) in Person_Implementations	0.5	double
	realtime_informed_vehicle_market_share	if (Uniform_RNG.Next_Rand <= parameter), then _enroute_information_type = WITH_REALTIME_INFORMATION, else NO_REALTIME_INFORMATION in Vehicle_Implementation	0.5	double
	information_compliance_rate_mean	what average proportion of travelers respond to the ITS warnings	1	double
	information_compliance_rate_standard_deviation	standard deviation for information_compliance_rate_mean	0.5	double
	minimum_travel_time_saving_mean	saved as mtts mean to compute triangular_random_variable in Vehicle_Implemenation	1	double
	use_realtime_travel_time_for_enroute_switching	if true, then call realtime_forward_link_turn_travel_time; set as use_realtime_travel_time in Turn_Movement_Implementation	FALSE	bool
	minimum_delay_ratio_for_enroute_switching	threshold for the ratio of delay time / travel time before agents will consider switching route due to outside information	3	double
	minimum_delay_seconds_for_enroute_switching	threshold for the absolute delay time before agents will consider switching route due to outside information	300	double
	enroute_switching_on_excessive_delay	whether to enable enroute switching for travelers who have been delayed significantly	TRUE	bool
	fix_connectivity_penetration_rate_cv	if true then the CV fleet will be synthesized using a fixed proportion of connected vehicles. The rate to be used is specified in the 'connectivity_penetration_rate_cv' parameter	nan	nan
	connectivity_penetration_rate_cv	Specifies the fixed proportion of connected vehicles in the synthesized CV fleet (if fix_connectivity_penetration_rate_cv is true)	nan	nan
	minimum_seconds_from_arrival_for_enroute_switching	0	300	double
	jam_density	Jam density (for all road types) in vehicles per mile per lane	0	integer
	convergence_mode	Sets up a special mode of fixed-trips (no mode choice, etc) for DTA convergence	nan	nan
	capacity_expressway	Maximum throughput of expressway in veh/h/lane	0	integer
	capacity_arterial	maximum throughput of arterials in veh/h/lane	0	integer
	capacity_local	maximum throughput of locals in veh/h/lane	0	integer
	traffic_midblock_start_end	Trips start and end at midblock as opposed to starting at the beggining of first link and ending when enters the last link.	nan	boolean
	force_no_street_parking_in_all_links	Curb impacts (next parameter) applies when the road has no street parking. Forcing it not to have will make all links prone to vehicles to block lanes when finishing its trip	nan	boolean
	curb_hold_for_curb_time	vehicles block up to one lane by a certain time when the trip ends	nan	boolean
	curb_lanes_blocked	value between 0 and 1 stating the share of a lane capacity is lost by a stopped vehicle	nan	float
	curb_time_sov_seconds	Time in which lane is blocked by the end of the trip for SOV vehicles	nan	integer
	curb_time_tnc_seconds	Time in which lane is blocked by the end of the trip for TNC vehicles	nan	integer
	curb_time_freight_seconds	Time in which lane is blocked by the end of the trip for freight vehicles	nan	integer
	speed_delta_logging	when traffic model == "LAGRANGIAN" it sets as threshold for storing speed trajectory. Consecutive sample speeds within the threshold may be grouped	nan	float
	threshold_conflicting_all_stop_seconds	0	0	0
	threshold_conflicting_two_way_stop_seconds	0	0	0
	threshold_conflicting_signalized_seconds	0	0	0
	spacing_shift_by_mode	A dictionary from mode string to the desired spacing shift to be used in the traffic simulation	nan	string
Output controls	deflate_level	The compression level to use for HDF outputs, higher levels give better compression at the expense of runtime	3	int
	write_activity_output	if true, then log Person_Scheduler_Implementations and output with Person_Data_Logger_Implementations	FALSE	bool
	write_demand_to_database	if true, then write person data log to demand sqlite database	FALSE	bool
	count_integrated_in_network_vehicles_only	if true, then decrement or increment in-network vehicles counter in Link_Implementation	FALSE	bool
	output_directory	The directory into which all simulation outputs will be writen; if a relative path is provided it will be interpreted relative to the model_directory	0	string
	write_node_control_state	if true, then run function by the same name in Network_Implementation_Results	FALSE	bool
	write_network_link_flow	if true, then run function by the same name in Network_Implementation_Results	FALSE	bool
	write_network_link_turn_time	if true, then run function by the same name in Network_Implementation_Results	FALSE	bool
	write_output_summary	if true, then run function by the same name in Network_Implementation_Results	TRUE	bool
	output_link_moe_for_simulation_interval	if true, then output link moe in each simulation interval	FALSE	bool
	output_turn_movement_moe_for_simulation_interval	if true, then output link moe to database and output turn movement moe in Network_Implementation_Results	FALSE	bool
	output_network_moe_for_simulation_interval	if true, then output network level MOE stats to csv at each simulation interval	FALSE	bool
	write_vehicle_trajectory	if true, write a sample of vehicles trajectories to the Path tables	FALSE	bool
	vehicle_trajectory_sample_rate	the proportion of vehicles to write trajectory data for	1	double
	write_skim_tables	if true, then open output files: highway, transit, and highway cost in NetworkModel	FALSE	bool
	output_highway_skim_file	one of three files written when write_skim_tables is true in NetworkModel	highway_skim_file_out.txt	string
	output_transit_skim_file	one of three files written when write_skim_tables is true in NetworkModel	transit_skim_file_out.txt	string
	write_planned_activity_table	if true, then write activities at plan time to Planned_Activity table. Includes dropped activities due to planning failures. This is mainly used for debuging.	FALSE	bool
	output_link_moe_for_assignment_interval	if true, then output link moe to database in Network_Implementation_Results	FALSE	bool
	output_turn_movement_moe_for_assignment_interval	if true, then output turn movement moe to database in Network_Implementation_Results	FALSE	bool
Population synthesizer controls	read_population_from_database	Controls how population is generated, read from Demand database (True) or synthesized (False)	FALSE	bool
	percent_to_synthesize	The population sampling rate, it should be balanced by an appropriate traffic_scale_factor. It also affects the proportion of population read from the database when not synthesising.	1	double
	ipf_tolerance	assigned to Tolerance in Solver_Settings_Implementation	0.01	double
	marginal_tolerance	...	5	int
	maximum_iterations	assigned to Iterations in Solver_Settings_Implementation	100	int
	write_marginal_output	if true, then write data to "marginal_distributions.csv" and also output parameters used	FALSE	bool
	write_full_output	if true, then write data to "joint_distributions.csv" and also output parameters used	FALSE	bool
	popsyn_control_file	initialize PopSyn_Implementations with file path	popsyn_control_file.txt	string
	use_external_popsyn_solver	Use user-provided PopSynth IPF/Integerization functions from external DLL/SO	FALSE	bool
	external_popsyn_solver_filename	filename of the external PopSynth funcationality DLL/SO	PopSynAPI.dll	string
	replan	Controls whether various sub-models are re-run against a population read from database or if previous outputs from the DB are used. Allowed sub-keys are 'workplaces', 'transit_pass_holding', 'escooter_participation', 'vehicle_ownership', telecommute_frequency' and the default if not provided is false	FALSE	dict[string,bool]
	replan_workplaces	DEPRECATED, use replan parameter instead	nan	nan
	replan_mobility_options	DEPRECATED, use replan parameter instead	nan	nan
	replan_delivery_options	DEPRECATED, use replan parameter instead	nan	nan
	traffic_scale_factor	Scale for the traffic flow model for traffic flow discretization; value 1 means no scaling applied; lower value updates capacity and jam density linearly	0	float
Routing and skimming controls	aggregate_routing	if true, then reset route planning in Activity_Implementations and used to determine aggregation properties in Person_Mover_Prototype	FALSE	bool
	input_highway_skim_file	one of three files read when write_skim_tables is true in NetworkModel	0	string
	input_transit_skim_file	one of three files read when write_skim_tables is true in NetworkModel	0	string
	read_skim_tables	if do_skimming is true, then set parameter to read_input; if read_input is true then set read_transit and read_highway_cost = true, but set to false if corresponding input file cannot be opened	FALSE	bool
	skim_averaging_factor	Weight applied to skims generated during simulation before averaging with (1-weight) applied to skims read in from input	nan	nan
	skim_minimum_sov_speed	A mimimum speed threshold to be applied to the skimmed travel times (relative to the skimmed distance)	5	float
	skim_interval_endpoint_minutes	if parameter is not found, then use_skim_intervals = false and search for skim_interval_length_minutes and set do_skimming = true in Scenario_Prototype	0	IntArray
	skim_interval_length_minutes	if skim_interval_endpoint_minutes is not found, then read parameter	1440	int
	enroute_switching_enabled	if true, then call check_enroute_switching in Vehicle_Implementation	TRUE	bool
	time_dependent_routing	if true, then call initialize_moe_data; if true, then call construct_time_dependent_routable_network in Network_Implementation;if false, then call compute_static_network_path, else call compute_time_dependent_network_path in Routing_Implementation and Vehicle_Implementation	FALSE	bool
	time_dependent_routing_weight_shape	save as _ttime_weight_shape in Routable_Network_Implementation	2	double
	time_dependent_routing_weight_scale	save as _ttime_weight_scale in Routable_Network_Implementation	1000	double
	time_dependent_routing_weight_factor	save as _ttime_weight_factor in Routable_Network_Implementation	1	double
	time_dependent_routing_weight_factor_affects_choice	If true, MSA based approach (factor=1/iteration_num) is applied in conjunction with the gap based approach for rerouting decision. If false - only gap is used.	nan	nan
	time_dependent_routing_weight_factor_affects_calculation	If true, information mixing on link travel time calculation is affected by the TDR weight factor (i.e. 1/iteration_num).	nan	nan
	time_dependent_routing_gap_calculation_strategy	time_dependent_routing_gap_calculation_strategy	nan	nan
	long_distance_trip_threshold_in_miles	The threshold (crow-flies miles) above which a trip is considered 'long-distance' for adding additional 'stop' penalties at traffic signals or stop signs	nan	float
	long_distance_freight_stopping_penalty	The additional routing 'stop' penalty (seconds) added to 'long-distance' freight trips at traffic signals or stop signs	nan	float
	long_distance_passenger_stopping_penalty	The additional routing 'stop' penalty (seconds) added to 'long-distance' passenger trips at traffic signals or stop signs	nan	float
	multimodal_routing	enable multimodal logic	0	bool
	EV_charging	Flag to control if detailed electric vehicle behavior is modeled (includes discharging, queueing at charging station, SoC tracking)	nan	nan
	use_ML_model_for_battery_discharge	Flag to control whether the TensorflowLite model is used for predicting electric vehicle discharging	nan	nan
	ML_model_filename	TensorflowLite model name to predict link-level electric vehicle discharging	nan	nan
	use_heterogenous_VOT	Allows person and trip-specific VOT values for weight in the generalized cost of routing	nan	nan
	multimodal_routing_model_file	pass parameter into routable_network_type	0	string
Scenario controls	cav_market_penetration	if Next_Rand <= parameter, then autonomous vehicle capability is set true, else is set false in Vehicle_Implementation	0	double
	cav_vott_adjustment	if autonomous vehicle capability is set true, then return parameter from Value_of_Travel_Time_Adjustment in Person_Properties_Implementation	1	double
	simulate_cacc	if parameter is true, then update capacity_adjustment_factor in Link_Implementation	FALSE	bool
	flexible_work_percentage	if Uniform_RNG.Next_Rand < parameter, then set flex_work = 1.0 in Telecommute_Choice_Implementation	0.12	double
	use_tmc	if use_network_events is true, then if parameter is true, then initialize Traffic_Management_Center interface in Integrated_Model	FALSE	bool
	use_network_events	if true, then initialize Network_Event_Manager interface; if true then subscribe events in Integrated_Model	FALSE	bool
Shared Mobility Controls	use_micromobility	Enable using micromobility operators and dockless fleets	FALSE	bool
	micromobility_fleet_model_file	Micromobility operations-related parameter file name	nan	string
TNC Controls	tnc_operator_chooser_model_file	File name that holds parameters related to the operator chooser choice model	nan	string
	tnc_fleet_model_file	File name that holds parameters needed to initialize and run the TNC module	nan	string
	use_tnc_system	Boolean that sets whether we use the on-demand TNC module	nan	boolean
	tnc_feedback	Boolean to improve TNC operations using historical data	nan	boolean
	tnc_driver_model_file	File name that holds parameters related to modeling human drivers in the TNC module	nan	nan
Unknown Grouping	simulation_year	The year in which the simulation is occurring	nan	nan
	snapshot_period	interval of time (seconds) between network snapshot write events	300	int
	do_planner_routing	if true, then Schedule_New_Routing and assign the movement plan to the persons activity schedule in Activity_Implementations	FALSE	bool
	vehicle_tracking_list_file_name	if parameter is not found, then use_vehicle_tracking_list = false, else vehicle_trajectory_sample_rate = 0.0 and use_vehicle_tracking_list = true	0	string
	compare_with_historic_moe	if true and start_of_current_simulation_interval_absolute % assignment_interval_length == 0, then call read_historic_link_moe function in Network_Implementation	FALSE	bool
	historic_network_moe_file_path_name	if compare_with_historic_moe is true, then open input file and throw exception if not successful in Scenario_Prototype	historic_realtime_moe_network.csv	string
	historic_link_moe_file_path_name	if compare_with_historic_moe is true, then open input file and throw exception if not successful in Scenario_Prototype	historic_moe_link.csv	string
	read_normal_day_link_moe	if true and start_of_current_simulation_interval_absolute % assignment_interval_length == 0, then call function with same name in Network_Implementation	FALSE	bool
	normal_day_link_moe_file_path_name	if read_normal_day_link_moe is true, then open input file and throw exception if not successful in Scenario_Prototype	normal_day_moe_link.csv	string
	historic_demand_moe_directory	0	0	string
	output_network_moe_for_assignment_interval	if true, then output network moe to database in Network_Implementation_Results	FALSE	bool
	load_analyze_link_groups_from_file	if true, then call read_analyze_link_groups in Network_Implemenetation	FALSE	bool
	analyze_link_groups_file_path_name	0	analyze_link_groups	string
	write_ttime_distribution_from_network_model	if true, then call write_ttime_distribution function in Network_Implementation	FALSE	bool
	vehicle_trajectory_output_threshold	0	-1	int
	vehicle_taking_action	if true, then make_suggestion( MOVE_TO_NEXT_LINK ) in Turn_Movement_Implementation;if true, then call start_agent function in Vehicle_Implementation	FALSE	bool
	relative_indifference_band_route_choice_mean	saved as rib mean to compute triangular_random_variable in Vehicle_Implementation	0.1	double
	multimodal_network_input	if false, then call clean_isolated_intersections; if true then set do_this_link = true; if true then set do_this_connection = true in Network_DB_Reader_Implementations	FALSE	bool
	enroute_excessive_delay_factor	used in above condition for minimum_delay_ratio_form_enroute_switching	1	double
	EV_default_Wh_per_mile	Default value to convert Wh needed to travel one mile in an electric vehicle	nan	nan
	accident_event_duration_reduction	save as _end_time = _end_time * accident_event_duration_reduction in Network_Event_Implementations	1	double
	calculate_realtime_moe	if true, then call calculate_moe_for_simulation_interval in Intersection_Implementation; call calculate_realtime_network_moe and output_moe_for_simulation_interval in Network_Implementation	TRUE	bool
	buildings_geometry_file	if parameter is not found, then use_buildings = false in Scenario_Prototype	0	string
Vehicle Choice Model	vehicle_distribution_file_name	initialize vehicle choice model with parameter in Integrated_Model	vehicle_distribution.txt	string

EVCS Generation Parameters

These are the electric vehicle charging station (EVCS) Generation parameters that control siting and sizing new EVCS. The parameters are contained within the file that is specified in the scenario.json via parameter evcs_generator_file_name.

These parameters are read in in the EV_Charging_Station_Generator_Methods.h header file.

Category	Parameter Name	Description	Default	Data Type
EVCS Generator Controls	generator_strategy	String that specifies which strategy is being loaded for EVCS siting	nan	string
	MAX_EVCS_DIST_MILES	Maximum distance in miles to reach the next nearby EVCS, instead of instantly generating a new one	10	float
	MAX_EVCS_WAIT_MINUTES	Maximum wait time in minutes at an EVCS before a new DCFC plug is generated	30	float
	capital_cost_evcs_gen	One-time cost in dollars to generate a new EVCS	100000	float
	evcs_life_span	Expected duration of operations of an EVCS for cost comparison	10	float
	capital_cost_added_plug	One-time cost in dollars of generating a new DCFC plug	1000	float
	land_cost_evcs_gen	Vector of land cost by area type to consider when siting an EVCS	nan	FloatArray
	default_unit_price_charged_per_kwh	Default cost in dollar per KWh charged when using a newly generated charging station	0	float
	EVCS_MAX_DCFC_PLUGS	Max number of DCFC plugs allowed for generation at any single EVCS	nan	integar
	EVCS_MIN_DCFC_PLUGS	Starting default number of plugs at a generated EVCS	3	integar
	EVCS_MAX_QUEUE	Threshold of queue length beyond which an additional plug is added if generating new EVCS	nan	integar