LIDAR-based roadway and roadside modelling for sight distance studies

Sight distance is a key aspect of road design and operation because of its relationship to traffic safety. The most realistic procedures for calculating the section of roadway visibility to the driver require the use of digital elevation models (DEM), which represent both the roadway itself and the features along the roadside. In this study, the influence of different types of DEM, an essential asset in sight distance analysis, is evaluated. Digital terrain models (DTMs), which represent the bare ground surface, and digital surface models (DSMs) that also consider elements above the terrain have been utilised. Both are high-resolution models obtained through airborne Light Detection and Ranging (LIDAR) or terrestrial vehicle (Mobile Mapping System, MMS). In addition, this study shows the influence of roadside vegetation on sight distance, revealing the underlying difficulties and suggesting possible solutions for sight distance studies when using these models.