In recent years, mixed or / and augmented reality, which aims to integrate virtual space with real space, has received a significant amount of attention in research and development.In particular, the concept of a tangible interface is an interesting research area in this growing field of study.This article develops and evaluates a tangible terrain representation system (TTRS), a tangible interface that recognizes the terrain in three dimensions and provides a more efficient approach to highway route planning and design.The developed system was evaluated by comparing its usability to an alternative system using a group of participants.The article concludes that TTRS is an effective tool for terrain representation and highway route planning and design.