Development and Implementation of a Beam-Bridging Filter for Use in Airport Groove Identification

Transverse grooves on runways prevent hydroplaning of aircraft at high speeds and are therefore a vital component of air safety. This paper proposes, for accurate identification of groove geometry, a new type of beam-bridging filter that uses a mechanical model to reduce the influence of short dips in pavement elevation profiles. This approach can adjust the effect of a tire's contact with the road surface by modeling the contact area as a beam element with a series of compressive springs. If small dips or grooves with a characteristic length significantly less than the length of the tire contact length are present in the pavement profile, the beam-bridging filter simulates a bridge over the dips or grooves as would be formed by the tire's contact with the ground. The beam-bridging filter is compared with other types of bridging filters: (a) the physical straightedge method, (b) simulation of a profilograph wheel, (c) the FHWA bridging (moving-average) filter, and (d) the University of Michigan Transportation Institute's bridging (improved moving-average) filter. Application of the bridging filter is demonstrated by its incorporation into a computer program for transverse groove identification for use on longitudinal profiles of airport runways. The example demonstrates that using the proposed beam-bridging filter leads to improved groove identification over implementation of current low-pass filters.