A series of field operational tests completed by Washington State over a 10-year period has shown that electronic container door seals (E-seals) can increase the efficiency and improve the security of containerized cargo movement. Universal use of E-seals, along with the associated infrastructure, could provide notable improvements in security, container tracking, and transaction cost reductions. Testing in ports, border facilities, and on roadways proved that E-Seal technology works: E-Seals can accurately and automatically report on container status at choke points, and the records can be accessed online to verify seal location, status (tampered or untampered), date, and time. However, a number of institutional barriers are likely to delay or even forestall the adoption of E-seals. A lack of standards is a major issue, since the E-seals available today use many different frequencies, hindering their applicability to international trade flows. A further barrier is the acceptability and cost of E-seals to the container industry. Routine use of seals would require new software linkages and container sealing procedures, which could slow acceptance. Disposable seals, which eliminate the need to recycle E-seals, are not common because they need to be produced in large quantities to be low cost. E-seals acceptable to the industry also need to be proved in a real world trade environment and need to be functionally simple to reduce routine operational problems. Compatibility with existing highway transponders systems might also promote E-seal acceptance, since containers could be tracked on the roadway system.