Redistributing fleets based on new control totals

When the user has data on the expected joint distribution of the fleet across multiple categories, including Vehicle class, power train, ful and its vintage, as well as the distribution of the existing fleet, it is possible to use the Vehicle Redistribution procedure to run an Iterative-Proportional fitting over the original distribution to match targets, including the total fleet for each census tract in the modeled area.

sphinx_gallery_thumbnail_path = ‘../../examples/data_preparation/car_fleet.png’ Imports

import os
from os.path import join
from pathlib import Path
from tempfile import gettempdir

from polaris.prepare.vehicle_distribution_updater.vehicle_distribution_updater import RedistributeVehicles

All our files need to be inside the same folder (pth, below)

pth = Path(os.getcwd()).resolve(True).parent.parent.parent / "tests" / "data" / "prepare" / "vehicle_redistribution"

rv = RedistributeVehicles(
    model_dir=pth,
    veh_file="vehicle_distribution_chicago.txt",
    target_file="target_2040_low.csv",
    veh_codes_file="polaris_vehicle_codes.csv",
    zone_weights="veh_by_zone_chicago.csv",
    fleet_mode=False,
)

Processing and saving results

The convergence threshold can be as low as required, as it is nearly guaranteed to converge

rv.process(conv_threshold=0.001, max_iterations=50)

# Two convergence scatter plots are also saved with the outputs for a quick sanity check
rv.save_results(join(gettempdir(), "veh_distr.csv"))

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Iteration 1: 0.0s , error 0.01668
Iteration 2: 0.0s , error 0.00136
Iteration 3: 0.0s , error 0.00011
Total processing time: 0.1s

Looking at the outputs

import pandas as pd

df = pd.read_csv(join(gettempdir(), "veh_distr.csv"))
df.head()

	TRACT	POLARIS_ID	VEHICLE_CLASS	FUEL	POWERTRAIN	VINTAGE	PROPORTION
0	17007010100	1034	CAR_COMPACT	Gas	ISG	1	0.013509
1	17007010100	1035	CAR_COMPACT	Gas	ISG	2	0.014122
2	17007010100	1042	CAR_COMPACT	Gas	PHEV	0	0.000844
3	17007010100	1043	CAR_COMPACT	Gas	PHEV	1	0.000844
4	17007010100	1044	CAR_COMPACT	Gas	PHEV	2	0.000885