Plot summaries
Light / heavy vehicle counts show the 7-day rolling
median change in light / heavy vehicle counts in 2026 relative to the
equivalent day in 2025, aligned by day of week and week number to
preserve weekly patterns (e.g. weekdays vs. weekends). Each day’s
vehicle count is normalised by the 9–22 February median which provides a
baseline for monitoring the impact of the fuel supply disruption. Only
those counters with data in the baseline period for 2026 are used in the
analysis. Due to data latency there is a delay of 7 days to 1 month in
updates for individual sites.
Heavy commercial VKT shows the daily total vehicle
kilometres travelled by heavy commercial vehicles if the trip goes
through any of 5 key freight areas: Auckland, Wellington City,
Christchurch City, Taupo District, Horowhenua District territorial
authorities.
PT boardings - Auckland shows the total daily
boardings on Auckland public transport for bus, rail and ferry. Totals
are calculated from payment tag on with either HOP or contactless bank
cards.
PT boardings - Wellington shows the total daily
boardings on Wellington regional public transport for bus and rail.
Totals are calculated from payment tag on with Snapper cards as well as
contactless payments.
PT boardings - Canterbury shows the total daily
boardings on Canterbury regional public transport for bus and ferry. The
daily boardings include all ticket types including Motu Move, SGC,
transfers etc.
Aviation departures - scheduled services (inc.
freight) shows the scheduled flights by airport and includes
both domestic and international flights.
Detailed methodology
Light / Heavy vehicle counts
These plots show the rolling median of the regional weighted-mean
change in Traffic Monitoring for State Highways (TMS) counts relative to
the pre-conflict baseline (9–22 February 2026). TMS data is retrieved
regularly from NZTA’s public API. The data processing methodology is as
follows:
- Only Continuous and National monitor types are used. The input data
is provided by vehicle weight and direction, and this is retained
throughout the processing.
- For each site-direction and vehicle weight, compute the daily
traffic ratio (2026 / 2025) by matching days on week-aligned
day-of-year, so that e.g. Monday week 5 in 2026 is compared to Monday
week 5 in 2025.
- The week-day alignment does not account for holidays occuring at
different times/days of the year (e.g. Easter)
- Normalise each site’s ratio by its median ratio during the baseline
window (9–22 February 2026).
- Remove outlier sites whose baseline ratio falls outside the 5th–95th
percentile nationally within each vehicle weight.
- Aggregate normalised ratios across sites by region using a
count-weighted mean.
- Apply a 7-day trailing rolling median to smooth day-of-week
variation.
- Any increases or decreases can be seen up to 7 days after the event
in the smoothed line due to the seven day look back period (e.g 2026
Easter period was from 3-6 April, but the point for 6th April is
included in the 7-day smoothing until April 12th)
Heavy commercial VKT
These plots show the rolling mean of total vehicle kilometres
travelled (VKT) of heavy commercial vehicles as represented in the
CompassIoT data (around 90% of the heavy fleet). Full trip VKT tallied
if it includes travel within any of 5 key freight areas: Auckland,
Wellington City, Christchurch City, Taupo District, Horowhenua District
territorial authorities.
Auckland - bus + rail + ferry
- Boardings for bus, rail and ferry.
- Boardings represent the number of individual passenger trips, i.e. a
bus to bus transfer counts as 2 boardings.
- Does not include untagged rail (i.e. Cash/Supergold). Untagged bus
boardings are included.
- Counts for 23-26 March 2026 are estimated due to lack of data
availability.
Wellington - bus + rail
- Boardings for bus and rail only. Ferry trips are not included.
- Boardings represent the number of individual passenger trips, i.e. a
bus to bus transfer counts as 2 boardings.
- Does not include untagged rail (i.e. Cash/Supergold). Untagged bus
boardings are included.
- Does not include trips where buses replace trains. The Metlink
website provides current (and next month) days of bus replacements by
line e.g. https://www.metlink.org.nz/assets/Buses-replacing-trains/Buses-replace-trains-HVL-2026-Apr-May.pdf.
Canterbury - bus + ferry
- Boardings for bus and ferry.
PT boardings - year on year analysis
- Sum the total boardings across modes for each region
- Compute the boarding ratio by matching days on week-aligned
day-of-year, so that e.g. Monday week 5 in 2026 is compared to Monday
week 5 in 2025.
- The week-day aligning does not account for holidays occuring at
different times/days of the year (e.g. Easter)
- Normalise each region’s ratio by its median ratio during the
baseline window (9–22 February 2026).
- This adjusts for pre-existing trends. e.g. if Wellington boardings
were already running below 2025 levels before the crisis, dividing by a
baseline ratio of less than 1 scales the post-crisis numbers back up,
isolating the fuel crisis’s effect.
- Apply a 7-day trailing rolling mean to smooth day-of-week variation.
- Any increases or decreases can be seen up to 7 days after the event
in the smoothed line due to the seven day look back period (e.g 2026
Easter period was from 3-6 April, but the point for 6th April is
included in the 7-day smoothing until April 12th)
Aviation departures - scheduled services (inc. freight)
- Departures only for both international and domestic.
- Airports: AKL (Auckland), CHC (Christchurch), WLG (Wellington), ZQN
(Queenstown).
- For future dates - number of scheduled flights including freight,
schedule goes about 6 months ahead
- This data is provided by Airport Coordination Limited (ACL).