9 10 Runway pavement grooving has been commonly constructed to reduce aircraft 11 hydroplaning risk and the loss of pavement skid resistance during wet weather. In a 12 recent Federal Aviation Administration (FAA) experimental study, a new trapezoidal 13 grooving design for runways was found to offer several benefits over the current FAA 14 standard square grooving design, including improved water evacuation capability, greater 15 resistance to rubber contamination, better integrity, and improved longevity. However, 16 the experimental study did not produce conclusive findings on the relative skid resistance 17 and hydroplaning performance of the two grooving designs. This is a critical issue of 18 concern as one must ensure that in the process of improving the durability, integrity and 19 longevity of the grooves, the safety performance (skid resistance and hydroplaning risk in 20 particular) of the grooved pavement is not compromised. To address this issue, this paper 21 presents a finite element simulation model to evaluate analytically the relative skid 22 resistance and hydroplaning performance of the two grooving designs. Also presented is 23 another finite element model to evaluate their drainage capacities to explain their 24 different hydroplaning and skid resistance performance. The results show that the 25 trapezoidal grooving design gives marginally lower skid resistance at low aircraft sliding 26 speeds, but its better drainage capacity allows it to maintain slightly higher skid 27 resistance than the square grooving design at high sliding speeds. On hydroplaning, the 28 trapezoidal grooving design offers slightly lower hydroplaning risk due to its better 29 drainage capability. 30