Shared Mobility Parameters

Shared Mobility Parameters#

Parameter related to modeling and simulation a shared fleet are described here. Primarily, the shared mobility parameters are contained within the file specified by tnc_fleet_model_file in the scenario file. The typical filename for these parameters is TNCFleetModel.json. You may also come across instances of SAVFleetModel.json or ChicagoTNCFleetModel.json.

The remaining page describes parameters at the TNC Operator level first and strategy-specific parameters follow.

TNC Operator Chooser Model Parameters#

These are the decision parameters on choosing operators as well as choice model parameters that control how operators are chosen from those available. The parameters are contained within two files that are specified in the scenario.json via parameter tnc_fleet_model_file and tnc_operator_chooser_model_file.

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

Category

Parameter Name

Description

Default

Data Type
ASCs

ASC_DRS_YES

Alternative specific constant with dynamic ride sharing (pooling)

nan

float

ASC_DRS_NO

Alternative specific constant without dynamic ride sharing (pooling)

nan

float

ASC_DRS_YES_SIX_SEATER

Alternative specific constant for six-seater vehicle with dynamic ride sharing (pooling)

nan

float

ASC_DRS_NO_SIX_SEATER

Alternative specific constant for six-seater vehicle without dynamic ride sharing (pooling)

nan

float

ASC_DRS_YES_FOUR_SEATER

Alternative specific constant for four-seater vehicle with dynamic ride sharing (pooling)

nan

float

ASC_DRS_NO_FOUR_SEATER

Alternative specific constant four-seater vehicle without dynamic ride sharing (pooling)

nan

float

ASC_DRS_YES_SIX_SEATER_STANDARD

Alternative specific constant for six-seater economy vehicle with dynamic ride sharing (pooling)

nan

float

ASC_DRS_YES_SIX_SEATER_LUX

Alternative specific constant for six-seater luxury vehicle with dynamic ride sharing (pooling)

nan

float

ASC_DRS_NO_SIX_SEATER_STANDARD

Alternative specific constant for six-seater economy vehicle without dynamic ride sharing (pooling)

nan

float

ASC_DRS_NO_SIX_SEATER_LUX

Alternative specific constant for six-seater luxury vehicle without dynamic ride sharing (pooling)

nan

float

ASC_DRS_YES_FOUR_SEATER_STANDARD

Alternative specific constant for four-seater economy vehicle with dynamic ride sharing (pooling)

nan

float

ASC_DRS_YES_FOUR_SEATER_LUX

Alternative specific constant for four-seater luxury vehicle with dynamic ride sharing (pooling)

nan

float

ASC_DRS_NO_FOUR_SEATER_STANDARD

Alternative specific constant for four-seater economy vehicle without dynamic ride sharing (pooling)

nan

float

ASC_DRS_NO_FOUR_SEATER_LUX

Alternative specific constant for four-seater vehicle without dynamic ride sharing (pooling)

nan

float
Cost Parameter

B_COST_DRS_YES_SIX_SEATER_STANDARD

Cost coefficient for six-seater economy vehicle with dynamic ride sharing (pooling)

nan

float

B_COST_DRS_YES_SIX_SEATER_LUX

Cost coefficient for six-seater luxury vehicle with dynamic ride sharing (pooling)

nan

float

B_COST_DRS_NO_SIX_SEATER_STANDARD

Cost coefficient for six-seater economy vehicle without dynamic ride sharing (pooling)

nan

float

B_COST_DRS_NO_SIX_SEATER_LUX

Cost coefficient for six-seater luxury vehicle without dynamic ride sharing (pooling)

nan

float

B_COST_DRS_YES_FOUR_SEATER_STANDARD

Cost coefficient for four-seater economy vehicle with dynamic ride sharing (pooling)

nan

float

B_COST_DRS_YES_FOUR_SEATER_LUX

Cost coefficient for four-seater luxury vehicle with dynamic ride sharing (pooling)

nan

float

B_COST_DRS_NO_FOUR_SEATER_STANDARD

Cost coefficient for six-seater economy vehicle without dynamic ride sharing (pooling)

nan

float

B_COST_DRS_NO_FOUR_SEATER_LUX

Cost coefficient for six-seater luxury vehicle without dynamic ride sharing (pooling)

nan

float
Nesting Coefficient

LAMBDA_DRS_YES

Nesting parameter for pooling nest

nan

float

LAMBDA_DRS_NO

Nesting parameter for non-pooling nest

nan

float

LAMBDA_DRS_YES_SIX_SEATER

Nesting parameter for pooling nest with six-seater vehicle

nan

float

LAMBDA_DRS_NO_SIX_SEATER

Nesting parameter for non-pooling nest with six-seater vehicle

nan

float

LAMBDA_DRS_YES_FOUR_SEATER

Nesting parameter for pooling nest with four-seater vehicle

nan

float

LAMBDA_DRS_NO_FOUR_SEATER

Nesting parameter for non-pooling nest with four-seater vehicle

nan

float
Service Choice

use_service_choice

Boolean to use service choice in the model or not. Triggers the use of parameters in the nested logit for service and seating choice.

nan

boolean
Time Parameter

B_IVTT_DRS_YES_SIX_SEATER_STANDARD

In-vehicle travel time coefficient for six-seater economy with dynamic ride sharing (pooling)

nan

float

B_IVTT_DRS_YES_SIX_SEATER_LUX

In-vehicle travel time coefficient for six-seater luxury vehicle with dynamic ride sharing (pooling)

nan

float

B_IVTT_DRS_NO_SIX_SEATER_STANDARD

In-vehicle travel time coefficient for six-seater economy vehicle without dynamic ride sharing (pooling)

nan

float

B_IVTT_DRS_NO_SIX_SEATER_LUX

In-vehicle travel time coefficient for six-seater luxury without dynamic ride sharing (pooling)

nan

float

B_IVTT_DRS_YES_FOUR_SEATER_STANDARD

In-vehicle travel time coefficient for six-seater vehicle with dynamic ride sharing (pooling)

nan

float

B_IVTT_DRS_YES_FOUR_SEATER_LUX

In-vehicle travel time coefficient for six-seater vehicle with dynamic ride sharing (pooling)

nan

float

B_IVTT_DRS_NO_FOUR_SEATER_STANDARD

In-vehicle travel time coefficient for six-seater vehicle without dynamic ride sharing (pooling)

nan

float

B_IVTT_DRS_NO_FOUR_SEATER_LUX

In-vehicle travel time coefficient for six-seater vehicle without dynamic ride sharing (pooling)

nan

float

TNC Fleet Model Parameters#

These are the TNC fleet model parameters that control the high-level fleet characteristics. The parameters are contained within the file that is specified in the scenario.json via parameter tnc_fleet_model_file.

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

Category

Parameter Name

Description

Default

Data Type
Electric TNC Vehicle

SAME_EV_RANGE_FLAG

Flag to set the EV range uniformly across the fleet for each operator

nan

boolean

EV_INITIAL_SoC_RANGE_FLAG

Flag to set the EV battery mean and std dev, if not all EVs will start with 100% battery

nan

boolean

SET_OF_EV_RANGES

Discrete set of EV range for assigning to vehicles in mi. Talk to Murthy before using this feature - may not work.

nan

IntArray

RANGE_DISTRIBUTION

Distribution of the different ranges in SET_OF_EV_RANGES for assigning to vehicles. Talk to Murthy before using this feature - may not work.

nan

FloatArray

EV_RANGE_MILES

If SAME_EV_RANGE_FLAG is True, specify the range of the EV in miles.

nan

float

EV_INIT_SoC_MEAN

If EV_INITIAL_SoC_RANGE_FLAG is true, the set the mean of the distribution in whole percent (for example, use 85 to denote 85%)

nan

float

EV_INIT_SoC_SD

If EV_INITIAL_SoC_RANGE_FLAG is true, the set the standard deivation of the distribution in whole percent (for example, for 1% use 1)

nan

float

Euclidian_Factor

Euclidean factor used to inflate distance used in approximate range utilization calculations before assigning requests to vehicles

nan

float
Fleet Characteristics

TNC_FLEET_SIZE

Fleet size of shared vehicles to simulate in the region. This will be scaled by the traffic_scale_factor within the simulation. Minimum value by default is 1.

nan

integer

TNC_MAX_WAIT_TIME

Maximum wait time in minutes used in searching for nearby vehicle candidates for matching. This time includes assignment and pickup time.

nan

float

TNC_WAIT_ASSIGNMENT_TIME

Maximum time to allow a request to wait for a vehicle match, after which the request will be failed.

nan

float

TNC_PREBOOKING_ASSIGNMENT_TIME

Time before a reservation to start looking for an assignment

nan

float

TNC_MAX_SEATED_CAPACITY

Default value for number of seats in all vehicles within the fleet. Will soon rely on vehicle characteristics for number of seats.

nan

float

delivery_type

String that specifies what types of requests are catered to by each operator. Possible options currently are "person", "meals_and_grocery", "relocator", and "mixed".

nan

string
Human Driver Operation

human_driver_ratio

Decimal fraction of vehicles in the fleet that are operated by human drivers

nan

float

human_request_cancellation_prob

Decimal probability of drivers cancelling a request

nan

float

human_driver_types_dist

Distribution of human drivers who may stay in place while not serving a trip, repoisition to zone expected to have high demand, reposition to zone expected to have high surge factor.

nan

FloatArray

driver_rating_min

Minimum value of driver rating when using a uniform distribution

nan

float

driver_rating_max

Maximum value of driver rating when using a uniform distribution

nan

float
Operational Constraints

geofence_flag

Flag to denote if the shared mobility service is limited to operate within a geofence

nan

boolean

geofence_zonebased_flag

If geofence_flag is true, flag to specific if the geofence is defined using zone IDs

nan

boolean

geofence_inclusion_zones

If geofence_zonebased_flag is true, set of zones where operator CAN serve trips

nan

IntArray

geofence_exclusion_zones

If geofence_zonebased_flag is true, set of zones where operator CANNOT serve trips

nan

IntArray

geofence_areatype_limit

If geofence_zonebased_flag is false, areatype limit less than within which the operator can serve trip

nan

float
TNC Demand

force_tnc_over_auto

Flag to force all auto demand to use shared mobility

nan

boolean

use_fmlm

Flag to set if operator supports pickups and dropoffs at transit stops for first-mile-last-mile trips

nan

boolean

magic_fmlm

Flag to allow router-only first-mile-last-mile trips without passing trips through to actual shared vehicles in the simulation. This means no wait time or travel delays are experienced.

nan

boolean

overwrite_input_party_size

Flag to set the distribution of request party size using an input, as opposed to reading it from the Demand database

nan

boolean

party_size_distribution

if overwrite_input_party_size is true, the distribution of 1,2,3, and 4-person parties can be set for generation

nan

FloatArray
TNC Maintenance

uniform_service_dist

Flag that controls if shared mobility maintenance is randomly distributed throughout the simulation day

nan

boolean

service_dist

Ability to specific the hourly probability distribution of when shared vehicles need to sent for maintenance/cleaning

nan

FloatArray
TNC Pooling

pooling_discount_for_fare

Percentage of discount offered on total fare when pooling ride is requested

nan

float
TNC Services and Operators

services_offered

Set of services offered by an Operator

nan

StringArray

dist_services_offered

Distribution of fleets by service type. It should sum to 1.

nan

FloatArray

market_capture_prob_for_loyalty

Market share of Operators (between 0 and 1)

nan

float
TNC Strategy

strategy_name

User-provided strategy name to define a collection of control-specific strategies to load that the operator will use. The name chosen here should be a section available in the input model file and should contain strategy-specific parameters.

nan

string

init_vehicle_state_strategy

Strategy name to load to initialize vehicle state for a run. Available options in the theory section on shared mobility.

nan

string

assignment_strategy

Strategy name to load for assignment or matching. Available options in the theory section on shared mobility.

nan

string

fare_strategy

Strategy name to load for setting fares after trip completion or to query an estimate before trip. Available options in the theory section on shared mobility.

nan

string

reposition_strategy

Strategy name to load repositioning control of fleet. Available options in the theory section on shared mobility.

nan

string

charging_strategy

Strategy name to load charging and discharging behavior. Available options in the theory section on shared mobility.

nan

string

maintenance_strategy

Strategy name to load for maintenance and cleaning of fleet. Available options in the theory section on shared mobility.

nan

string

parking_strategy

Strategy name to load to control parking between trips. Available options in the theory section on shared mobility.

nan

string
TNC_Operator

ZONE_BASED_ASSIGNMENT

Should always be true. Storage architecture for finding nearby vehicles.

nan

boolean

TNC_LOGGING_INTERVAL

Interval in minutes where outputs are logged to DB

nan

float

TNC Default Strategy Model Parameters#

These are the strategy parameters that decide how the TNC fleet operates during the simulation. The parameters are contained within the file that is specified in the scenario.json via parameter tnc_fleet_model_file.

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

Category

Parameter Name

Description

Default

Data Type
Default_Strategy

MAX_EVCS_WAIT_MINUTES

To be moved

nan

nan

EVCS_MIN_DCFC_PLUGS

To be moved

nan

nan

EVCS_MAX_DCFC_PLUGS

To be moved

nan

nan
Electric TNC Vehicle

MIN_EV_SoC

Minimum electric vehicle state of charge below which vehicle will stop accepting requests. Required by all strategies that use EVs.

nan

float

CUTOFF_BATTERY_LEVEL

The maximum battery level to charge the electric shared vehicle up to before charging is cutoff. Required by all strategies that support EV operation.

nan

float
Parking_Strategy

parking_flag

Flag that ensures shared vehicles park at a parking location if set. Required for all parking strategies.

nan

boolean

rideshare_minimize_park_cost

Flag that, when true, minimizes a parking cost that is a function of distance and money charged, and minimizes distance if false.

nan

boolean

rideshare_max_park_distance

Maximum parking distance in meters that is allowed.

nan

float

rideshare_max_park_cost

Maximum dollar charge for parking that is allowed

nan

float

rideshare_avg_park_time

Average parking time in minutes assumed for cost calculation when finding nearest parking

nan

float
Pooling

DRS_FLAG

Flag that controls if dynamic ride-sharing or pooling is active or not. Required for all matching strategies.

nan

boolean

DRS_MAX_ALLOWABLE_DELAY_SECONDS

Theoretic maximum allowable delay that any request can experience when pooled. Required for all matching strategies.

nan

float

DRS_MAX_PERC_DELAY

Theoretical maximum percentage delay compared to door-to-door travel time when pooled. Required for all matching strategies.

nan

float

directionality_threshold_degrees

Deviation in degrees from line connecting current trip's O to D relative to line connecting O to new request's pickup.

nan

float
Repositioning

repositioning_flag

Flag that controls if fleet repositions or not. Required for all repositioning strategies.

nan

boolean

repositioning_solver

String that is used to change the underlying fleet position optimization - can be any string supported by Google OR Tools (currently {'GLOP','SCIP','CBC','CLP','CP-SAT'}.

GLOP

string

demand_window_size

Fraction of an hour used to aggregate past demand for use as a predictor of future demand

nan

float

time_tradeoff

Travel time tradeoff in seconds above which repositioning is executed

nan

float

alpha

Factor of past demand used for prediction to ensure some smoothness in how many vehicles to reposition

nan

float
TNC Maintenance

SERVICE_FLAG

Flag that controls whether or not the shared fleet vehicles are periodically subject to maintenance and cleaning

nan

boolean

SERVICE_CONVENIENCE_FLAG

Flag that allows scheduling a maintenance trip if the vehicle's current destination is relatively close to a maintenance station

nan

boolean

SERVICE_DISTANCE

If SERVICE_CONVENIENCE_FLAG is true, then this is the distance in miles from current destination to a nearby maintenace depot that is allowed

nan

float

service_time

Time in minutes taken to perform service/maintenance

nan

float

clean_service_time

Time in minutes taken to perform vehicle cleaning

nan

float

max_service_trips_per_day

Maximum number of service/maintenance/cleaning trips that a shared vehicle can be subject to in a simulation day

nan

float

max_tours_before_cleaning

Maximum tour chains (a series of pickup and dropoffs in the case of pooling) before the vehicle needs to be cleaned

nan

float

Georgia Tech’s ODMTS Strategy Model Parameters#

Assignment strategy parameters used to initialize and operate Georgia Tech’s ODMTS pooling strategy. The parameters are contained within the file that is specified in the scenario.json via parameter tnc_fleet_model_file.

These parameters are read in in the TNC_Riley2018_Strategy_Methods.h header file.

Category

Parameter Name

Description

Default

Data Type

Joint Electric Vehicle Charging and Repositioning Strategy Model Parameters#

Assignment and repositioning strategy parameters used to initialize and operate UT’s joint EVCR strategy. The parameters are contained within the file that is specified in the scenario.json via parameter tnc_fleet_model_file.

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

Category

Parameter Name

Description

Default

Data Type
Electric TNC Vehicle

EV_LEVEL_UTILITY_INCREASE

The weight parameter (determined by modeler discretion) to increase charging by increasing the objective value (alpha in paper)

nan

nan

EV_SUPPLY_LEVEL_SOC

The minimum state of charge (SOC) for a vehicle to count as eligible for repositioning in a supply sense (say 40.0 for 40%)

nan

nan

EV_REPOSITIONING_MIN_SoC

Minimum level for a vehicle to be eligible for repositioning when reviewing idle vehicles to reposition (say 40 for 40%). 

nan

nan

CUTOFF_BATTERY_LEVEL

State of charge (SoC) when battery will stop charging (say 95.0 for 95%)

nan

nan

EV_QUEUE_FACTOR

Sets the number of available parking spots at the charging stations where vehicles can queue while waiting to charge (multiplied by # of plugs at the zonal level) (say 0.30). 

nan

nan
Joint_Charging_Repositioning_Strategy

time_tradeoff

Weight parameter (determined by modeler discretion) to penalize unmet demand, represented in the slack variable. It is also used to exclude faraway zones (by estimated travel time) for each eligible repositioning vehicle.

nan

float

alpha

Factor of past demand used for prediction to ensure some smoothness in how many vehicles to reposition

nan

float
Required Strategy Parameters

repositioning_flag

Flag that controls if fleet repositions or not. Required for all repositioning strategies.

nan

boolean

Stable Matching Strategy Parameters#

These are the strategy parameters specific to using the stable matching strategy that balances rider and driver preferences. The parameters are contained within the file that is specified in the scenario.json via parameter tnc_fleet_model_file.

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

Category

Parameter Name

Description

Default

Data Type
Algorithm Weights

ev_preference_factor

Preference weight for choosing an electric vehicle

nan

float

driver_rating_weight

Preference weight for driver rating of vehicle that is a viable candidate

nan

float
Pooling

DRS_FLAG

Flag that controls if dynamic ride-sharing or pooling is active or not. Required for all matching strategies.

nan

boolean

DRS_MAX_ALLOWABLE_DELAY_SECONDS

Theoretic maximum allowable delay that any request can experience when pooled. Required for all matching strategies.

nan

float

DRS_MAX_PERC_DELAY

Theoretical maximum percentage delay compared to door-to-door travel time when pooled. Required for all matching strategies.

nan

float
Preferences

matching_request_preference

Boolean to consider request preference matching in algorithm

nan

boolean

matching_vehicle_preference

Boolean to consider vehicle preference matching in algorithm

nan

boolean

Dynamic Fare Strategy Parameters#

These are the strategy parameters specific to using the dynamic fare setting policies. The parameters are contained within the file that is specified in the scenario.json via parameter tnc_fleet_model_file.

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

Category

Parameter Name

Description

Default

Data Type
Fare Controls

dynamic_fare_flag

Boolean to set whether fares vary dynamically throughout the simulation or a fixed per-mi, per minute, and base fare will be applied to request

nan

boolean

tod_fare_flag

Boolean for specific type of dynamic fare strategy that only is applied for particular times of day

nan

boolean

TOD_surge_factor

Factor applied to fares in the designated times of day to surge fares

nan

float

zone_surge_multiplier_flag

Maximum factor applied to fares in particular zones that meet demand and supply criteria to surge fares

nan

float

surge_calculation_interval

Simulation time in seconds to update the surges used for each zone

nan

float
Time Periods

rideshare_am_peak_period_start

Simulation time in hour of day to denote the start of AM peak period for ridehailing/ridesharing trips

nan

float

rideshare_am_peak_period_end

Simulation time in hour of day to denote the end of AM peak period for ridehailing/ridesharing trips

nan

float

rideshare_pm_peak_period_start

Simulation time in hour of day to denote the start of PM peak period for ridehailing/ridesharing trips

nan

float

rideshare_pm_peak_period_end

Simulation time in hour of day to denote the end of PM peak period for ridehailing/ridesharing trips

nan

float

Alonso-Mora et al.’s Ride-Sharing Strategy Parameters#

These are the parameters specific to running the AlonsoMora strategy for assignment. The parameters are contained within the file that is specified in the scenario.json via parameter tnc_fleet_model_file.

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

Category

Parameter Name

Description

Default

Data Type
Optimization

batched_interval_seconds

Interval in seconds to batch requests before applying matching optimization

nan

float

n_vehicles_per_request

Number of vehicles considered as a candidate for each request.

nan

integar
Pooling

DRS_FLAG

Flag that controls if dynamic ride-sharing or pooling is active or not. Required for all matching strategies.

nan

boolean

DRS_MAX_ALLOWABLE_DELAY_SECONDS

Theoretic maximum allowable delay that any request can experience when pooled. Required for all matching strategies.

nan

float

DRS_MAX_PERC_DELAY

Theoretical maximum percentage delay compared to door-to-door travel time when pooled. Required for all matching strategies.

nan

float
Routing

TT_cutoff_for_routing_vs_skim_seconds

If strategy uses router to get travel time (instead of skims), the cutoff value below which the router is used.

nan

float