The length of 1500 metres comprises 35 experimental sections. The commercial traffic carried during the period of twenty years was 13.5 million standard axles. The object of the experiment is to investigate the effect of the following factors on the performance of a concrete road; thickness of concrete, strength of concrete, the amount of reinforcement and the type and thickness of sub-base. The main conclusions reached are that the thickness of the concrete slab is confirmed as the most critical factor affecting its performance; high-strength concrete continues to give significantly better results than normal concrete; lean-concrete sub-bases are more effective than granular sub-bases. Very heavy traffic can be catered for by appropriate selection of slab thickness, type and thickness of sub-base, and strength of concrete