Thermosyphons have been used to maintain permafrost below structures for over forty years. The Chena Hot Springs Road Test Section became operational during the fall of 1998 and includes three test sections underlain with different types of thermosyphons plus a control section. The test section overlays high-moisture-content permafrost. After two seasons, the thaw depth decreased and the freezing depth increased in all sections, including the control. Pavement edge temperatures showed a decided cooling trend which was slight for the control, more pronounced for the UAF/CRREL units and AFI flat loop evaporator units, and highest for the AFI buried units section. The centerline thermal conditions relate to the condenser size, while the pavement edge or shoulder conditions relate to the type of installation. During the winter season, the AFI buried condenser thermosyphons show surface warming and sublimation of snow closer to that of the control section, while the other two test sections are colder at the surface during the winter season.