Mean texture depth (MTD) is a primary factor influencing the skid resistance of road surfaces. Many researchers utilize 3-D laser imaging to calculate MTD of sand patch test, typically relying on pavement texture peaks to determine the top surface of sand patch. In reality, many of the texture peaks protrude above the sand patch surface and do not form part of the top surface sand patch. To address this issue and to improve the accuracy of MTD determination, this paper employs a new numerical method to compute pavement MTD. The concept of planation was employed to study the height distribution of the texture peaks. Based on analysis of field data from different road sections, it was found that using the 94th percentile height as the equivalent top surface height would achieve good accuracy in MTD calculation. Comparative analysis with past methods proposed by other researchers confirms the accuracy and effectiveness of this approach.