Speed on European Interchange Ramps: A Completed Correlation among Greek, Dutch & Russian Drivers

The present study was conducted on highway interchanges primarily designed for high-speed applications, featuring corresponding geometric elements with an average curve radius of 200m. For field measurements, six horizontal ramp curves of various types were selected: loops with medium radii (comparative to the radius value of most single-lane loop types) and semi-directional and directional ramps with medium to large radii. The Vericom equipment used measures speed every 0.1 second, and the sample consists of over 100 drivers of different ages, genders, and vehicle types. All measurements were taken under free-flow conditions and on dry road surfaces. The main aim of this study is to contribute to the international literature by providing a model that estimates the speed applied in interchanges by European drivers of different nationalities. A secondary aim is to identify which nations’ drivers are more accustomed to applying high speeds on interchange ramps. By doing so, the study seeks to inspire similar research outside of Europe, ultimately to determine whether speed is influenced by the cultural or socioeconomic characteristics of nations globally. Another objective is to explore how the equations linking the operating speed (V 85 ) and the curve radius of urban interchange ramps, resulted from previous research, differ when examining curves with medium to large radii on highways. Additionally, it investigates whether the model established by the previous research can be applied to curves with large radii both within and outside urban networks. The study concludes that the classification of driving behavior among Greek, Russian, and Dutch drivers remains consistent for large radius curves, with Dutch drivers being the most aggressive and Russian drivers the most conservative. However, measurements on interchanges with larger radii significantly reduced the speed interval between Greek and Dutch drivers for radii greater than 150m, and altered the classification for smaller radii, where Greek drivers were the fastest. The differentiation between the speed profiles of Greek drivers derived from each research led to the establishment of two separate models for predicting speed in Greek interchanges. Each model is recommended to complement geometric road design guidelines: the first, presented in previous research, concerns interchanges in urban road networks; the second, resulting from this study, concerns interchanges on highways.