Application of IHSDM Design Consistency Module and UK Operating Speed Prediction Model: A Case Study in the UK

Abstract

Operating speed and design consistency have been agreed upon as the two critical measures of highway design evaluation, and could help researchers to study the contributors to traffic accidents and black-spots on roads. In the UK, Hashim has developed the most recent model since the first operating speed prediction model published in 1989. Comparably, much more research has been conducted in the USA, and a lot of achievements have been made. The Interactive Highway Safety Design Model (IHSDM) is a suite of evaluation tools for highway geometric design. Both of the two models are mainly focused on two-lane rural highways which also dominate the primary road classification in the UK. The major goals of this research are to find out the effectiveness of the highway design evaluation solution - IHSDM - applied on UK roads, as well as the further possible developments of the model developed by Hashim. The background of the two models has been investigated; furthermore, they have been implemented on carriageways to systematically evaluate their practical feasibility in the UK, especially for IHSDM. The comparisons of predicted operating speeds with collected speeds, as well as the appraisal of the results with traffic accident data both have been achieved. Finally, the further tasks that are required to make IHSDM appropriate for the UK conditions are recommended, including calibration of IHSDM Design Consistency Module to local situations and verification of highway alignment data input procedures of IHSDM; moreover, based on the results of applying Hashim's model, the constructive suggestions for its further development have been also presented in this report.