<p>Thin fiber-reinforced concrete (FRC) overlays and pavements can be economic alternatives for rural roads. While thin concrete overlays have been in practice for several decades, the concept of thin FRC pavements directly on top of the granular aggregate base layer is relatively new and its structural design is still being developed. Thus, the structural responses and critical distress of such pavements shall be understood in great detail. This paper presents the results of a rare field study conducted to investigate the influence of synthetic macro-fibers on load transfer efficiency (LTE), environmental load-induced strain, and its effect on slab curvature. It was found that synthetic macro-fibers if added at an optimum dosage (0.33–0.75% volume fraction of concrete), can provide 30–40% higher LTE compared to thin plain concrete pavements. The variation of the LTE with the seasonal pavement surface temperature can be reduced by using synthetic macro-fibers. It was found that the curvature of the fiber-reinforced slabs was less than the plain concrete slabs, which is a result of the decrease in the curling stresses in concrete pavements. The field-validated joint performance results with respect to equivalent single axle load (ESAL), environmental strain values, and slab curvature results presented in this paper can be used in the development of the mechanistic-empirical design procedure for thin fiber reinforced concrete pavements.</p>