The advent of readily available Automatic Identification System (AIS) data, both as an archival record of marine vessel traffic as well as real-time informational feeds, has enabled the U.S. Army Corps of Engineers (USACE) to compile a Travel Time Atlas for the Inland Marine Transportation System (IMTS). This compendium of segment-level statistical summaries provides baseline measures against which future IMTS conditions may be compared, allowing for determination of performance trends through time and system-scale level of service assessments. When combined with River Information Services (RIS) and requisite back-end automation of transit time calculations, the Travel Time Atlas approach transforms into a real-time traffic monitoring capability for the IMTS. Marine operators, voyage planners, and government and industry decision makers will all benefit from a live view of IMTS traffic conditions, and future work will focus on extending these towards near-term projections of waterway traffic congestion.