US Air Freight and Waterway Volumes¶

A look at air and domestic waterway freight volumes, according to the US DOT Bureau of Transportation Statistics.

import pandas as pd
import altair as alt
from os import environ
import re

#if environ.get("GITHUB_WORKFLOW"):
#    raise RuntimeError("Requires manual updates")

def doComboChart(df, metric='AIR_RTMFM', title='US Air Freight Volume', label='Volume [ton-miles]', width=2):

    brush = alt.selection(type='interval', encodings=['x'])
    
    base = alt.Chart(df.reset_index()[['dt', metric]].dropna()).mark_line(color='purple').encode(
        alt.X('dt:T', axis=alt.Axis(title='')),
        alt.Y(f'{metric}:Q', axis=alt.Axis(title=label)),
        tooltip=[alt.Tooltip("dt:T", format="%b %Y"), alt.Tooltip(f"{metric}:Q", format=",.02f")]
    ).properties(
        width=750,
        height=400
    )

    upper = base.mark_bar(width=width, color='blue').transform_window(
        window=[alt.WindowFieldDef("lag", metric, param=12, **{ 'as': 'previous' })],
        sort=[{"field": "dt"}],
    ).transform_calculate(
        yoy=f"((datum['{metric}'] - datum.previous) / datum.previous) * 100"
    ).encode(
        alt.X('dt:T', axis=alt.Axis(title=''), scale=alt.Scale(domain=brush), impute=alt.ImputeParams(value=None)),
        alt.Y(f'yoy:Q', axis=alt.Axis(title='Year-over-Year Growth [%]'), impute=alt.ImputeParams(method='value', keyvals=[400, 1000])),
        color=alt.condition(f"datum['yoy'] < 0",
            alt.value('lightsalmon'),
            alt.value('royalblue')
        )
    ).properties(
        title=title,
    )
    
    lower = base.properties(
        height=100
    ).add_selection(brush)

    return (upper & lower).properties(background='white')

# https://data.bts.gov/Research-and-Statistics/Transportation-Services-Index-and-Seasonally-Adjus/bw6n-ddqk

df_af = pd.read_csv('https://data.bts.gov/api/views/bw6n-ddqk/rows.csv?accessType=DOWNLOAD')
df_af = df_af.iloc[:-1, 1:]
df_af.columns = ['dt'] + df_af.columns[1:].tolist()
#df_af.head()

Airline Freight¶

c = doComboChart(df_af)
c.save('transportation-air-waterway.png')
c.display()

Internal Waterways Shipping¶

doComboChart(df_af, metric='WATERBORNE', title='US Internal Waterways Shipping Volume', label='Volume [Million short tons]')

Rail Freight Carloads¶

doComboChart(df_af, metric='RAIL_FRT_CARLOADS', title='US Rail Freight Carloads', label='Carloads')

Rail Freight Intermodal¶

doComboChart(df_af, metric='RAIL_FRT_INTERMODAL', title='US Rail Freight Intermodal', label='Carloads')

Vehicle Miles Traveled¶

doComboChart(df_af, metric='VMT', title='US Vehicle Miles Travels', label='Miles')