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Use the Maritime Port Activity Index (MPAI) to monitor the operational health of US container ports and get ahead of congestion before it disrupts your supply chain. This page explains how Chainomics computes the MPAI, how to interpret each score band, and what actions to take when the index rises.

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What MPAI Is

The MPAI is a composite 0–100 score that measures US maritime port activity by aggregating nine underlying indicators published by the Bureau of Transportation Statistics (BTS). A single weekly number replaces hours of manual data gathering across vessel queues, throughput reports, and berth utilization tables. Higher scores indicate healthier, less-constrained port throughput. A score above 70 signals elevated congestion risk and warrants immediate attention from your operations team.

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The 9 Underlying BTS Indicators

Chainomics pulls nine BTS Inside-the-Gate metrics to compute the MPAI:
#IndicatorNotes
1Vessel callsTotal vessel arrivals at monitored US container ports
2Container throughputTEUs loaded and discharged per period
3Dwell timeAverage days a container sits inside the gate (inverted — higher dwell = lower score)
4Berth utilizationPercentage of available berth time occupied by vessels
5Rail-dray volumesIntermodal moves originating at port gates
6–9Additional BTS port activity signalsLoaded imports, containerized imports/exports, containership capacity, and repositioning (empty container) flows
Each indicator is min-max normalized over a 52-week rolling window to remove seasonal bias, then weighted and combined into the composite score.

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How the Score Is Calculated

MPAI = min-max normalization of (
  weighted sum of 9 BTS Inside-the-Gate indicators
  over a 52-week rolling trimmed mean
)
The 52-week rolling trim excludes statistical outlier weeks (e.g., holiday shutdowns or one-off storms) so the score reflects structural port conditions rather than noise. Chainomics recomputes the composite weekly, each time BTS releases updated reference data.

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How to Read the Score

Use this table to translate an MPAI reading into an operational posture:
BandScore RangeMeaning
Low0–39Significant congestion or capacity constraints. Supply chain impact is likely.
Moderate40–59Elevated stress. Pre-emptive action recommended.
Elevated60–69Normal throughput but trending toward pressure. Monitor closely.
High70–100Congestion risk active. Disruption to dwell times and carrier capacity probable.
Read the MPAI as a port-activity intensity gauge. Low scores (below 40) indicate that activity has dropped sharply — a sign of congestion or capacity constraints already disrupting throughput. High scores (above 70) indicate that activity is surging to the point where congestion risk becomes elevated and dwell times are likely to lengthen. The middle range (40–69) represents normal-to-stressed conditions. Both extremes warrant action from your operations team.

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How to Act on an Elevated MPAI Reading

1

Identify which ports are affected

Navigate to Maritime Ports in the sidebar. The MPAI breakdown table shows per-indicator scores so you can pinpoint whether congestion is driven by dwell time, berth utilization, queue depth, or throughput shortfalls.
2

Evaluate your exposure

Cross-reference the MPAI with your active shipment list. Use Ask Ms. Z to run a plain-English query: “Which of my shipments are at risk from current MPAI conditions?”
3

Reroute away from congested ports

If one load center is driving the MPAI spike, evaluate alternative ports of entry. Chainomics surfaces live border wait times and port congestion signals side by side so you can compare alternatives in one view.
4

Pre-book capacity

A rising MPAI typically precedes carrier capacity tightening at port-adjacent dray lanes by 24–48 hours. Contact your dray and intermodal carriers now, before spot rates reflect the congestion.
5

Deploy an MPAI-triggered AI agent

In AI Agents, build a no-code agent that monitors MPAI daily and sends you an email alert whenever the score crosses 70. Use the built-in Port Congestion Agent template as a starting point.

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Where to Find MPAI

  • Sidebar → Maritime Ports → Maritime Port Insights
  • Freight Indices Hub at chainomics.ai/freight-indices-hub — compare MPAI against PFPI, CBPSI, and SSI in the cross-signal explorer
  • Ask Ms. Z — type “What is the current MPAI?” from any page

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Data Attribution

The MPAI is proprietary intellectual property of Chainomics. Underlying raw data is sourced from the Bureau of Transportation Statistics (BTS), US Department of Transportation Inside-the-Gate port statistics. Chainomics does not alter or re-license raw BTS values — only normalizes them for display.