The Identification of road horizontal alignment inconsistencies – a pilot study from the Czech Republic

There is a problem with inappropriate speed consequences related to horizontal alignment of Czech rural roads. Evaluation of alignment consistency, i.e. the degree to which a road is designed and constructed to avoid critical driving manoeuvres, has been known as one of promising tools in this regard. The objectives of presented pilot study were (1) to prove the practical application on historical rural road, lacking design data, using low-cost technology, (2) to investigate the relation of obtained alignment consistency measures to actual safety, and (3) to propose further steps for practical implementation, e.g. for the needs of road agency. Given these objectives and literature review findings, GPS technology was chosen for data collection, with the aim of using alignment consistency levels. Pilot rural road section was approximately 2.5 km long and consisted of 3 straight segments and 3 curves. Data processing included determination of central trajectory, determination of horizontal alignment elements and segmentation, calculation of consistency measures, and identification of inconsistencies. The results are given in terms of the consistency level of individual curves, followed by validation by the results of accident data analysis. In the end, several practical applications are listed and described.