Measure of Effectiveness (Link Volumes)

Within the ModelName-Result.h5 data store, the Link and Turn MOE folders each have multiple tables (one per attribute). Each table is organized as a matrix with dimensionality Records x Timesteps.

More information related to reading and writing H5 tables using Python or C++ can be found in the Model Outputs documentation.

UID Conversion

Each record in the Link and Turn MOE tables is uniquely identified by its UID (link_uid and turn_uid respectively). These UIDs are related back to corresponding unique IDs in the Link and Connection tables in the Supply database by the following identities:

\[ \begin{align}\begin{aligned} T_{id} = T_{uid}\\ L_{id} = floor(L_{uid} / 2)\\ L_{dir} = L_{uid} \mod{2}\\ L_{uid} = 2 . L_{id} + L_{dir}\end{aligned}\end{align} \]

MOE Normalizer

Studio has a function to normalize a results MOE file according to a network file, for cases where the network may have slightly changed but we do not want to restart all runs. This can be called from here:

from polaris.runs.results.normalize_moe import normalize_moe

normalize_moe(network_path, results_path)

The function takes Path from pathlib as arguments, and will add or remove links and turns from MOE to match the network. It will also account for changes in the Restricted_Lanes table. We check for similarity in the tables (similar link counts and lengths), so this will not allow you ex. to normalize a Grid file against a Chicago network.

The function returns a boolean (True if we normalized successfuly, False if we failed or skipped).

Link MOE

The following provides an overview of the various data fields in the link_moe group of H5 file.

LinkMOE Attributes	Description	Units
link_travel_time	Average travel time experienced by travelers to traverse the link in the time slice	seconds
link_travel_time_standard_deviation	deprecated
link_queue_length	deprecated
link_travel_delay	Average delay experienced by travelers on the link in the time slice	seconds
link_travel_delay_standard_deviation	deprecated
link_speed	Average speed of vehicles traversing the link in the time slice	meters/second
link_density	The number of vehicles per mile per lane	veh/mi/lane
link_in_flow_rate	The number of vehicles per interval entering the link	veh/hr/lane
link_out_flow_rate	The number of vehicles per interval exiting the link	veh/hr/lane
link_in_volume	The number of vehicles entering the link in the time slice	# of vehicles
link_out_volume	The number of vehicles exiting the link in the time slice	# of vehicles
link_speed_ratio	Ratio of link_speed to free flow speed of link	No unit
link_in_flow_ratio	Ratio of current in-flow to in-flow capacity	No unit
link_out_flow_ratio	Ratio of current out-flow to out-flow capacity	No unit
link_density_ratio	Ratio of link_density to jam density	No unit
link_travel_time_ratio	Ratio of average travel time to free-flow travel time	No unit
num_vehicles_in_link	The number of vehicles presently traversing the link in the time slice	# of vehicles
volume_cum_MDT	Cumulative volume of Medium Duty vehicles on the link in the time slice	# of vehicles
volume_cum_HDT	Cumulative volume of Heavy Duty vehicles on the link in the time slice	# of vehicles
entry_queue_length	The number vehicles waiting to enter the link from outside the network in the time slice	# of vehicles
link_length	Length of the link	meters
link_uids	Link unique ID (derived from database ID and direction)	integer

Turn MOE

The following provides an overview of the various data fields in the turn_moe group of H5 file.

TurnMOE Attributes	Description	Units
turn_penalty	Time delay in executing a turn	seconds
turn_penalty_sd	deprecated
inbound_turn_travel_time	Travel time to reach turn from inbound link	seconds
outbound_turn_travel_time	deprecated
turn_flow_rate	Vehicle count in the time slice that left the turn (**volume and not flow rate)	# of vehicles
turn_flow_rate_cv	CV Vehicle count in the time slice that left the turn (**volume and not flow rate)	veh/hr/turn
turn_penalty_cv	Time delay in executing a turn for a connected vehicle	seconds
total_delay_interval	Total turn delay for vehicles in that interval experienced in the time slice	seconds
total_delay_interval_cv	Total turn delay for connected vehicles in that interval experienced in the time slice	seconds
turn_penalty_by_entry	Similar to turn penalty but based on vehicle step entrance and not when vehicle left the turn (used for DTA convergence)	seconds
turn_uids	Turn unique identifiers	integer

Additional metadata such as the start time and timestep length are also stored as attributes of each group (“link_moe” and “turn_moe”):

• num_records

• num_timesteps

• start_time

• timestep