An important element of achieving quality in a road network is the control of vehicle vibration due to pavement roughness and road irregularities. Scientific literature and international standards suggest that we evaluate these phenomena by measuring the whole body vibration (WBV) on the road user, but, for the practical aims of road engineering, this expression has to be related to road unevenness indexes, especially the most common one (the international roughness index, IRI). This index, in turn, is obtained from measured pavement geometric data using a conventional model of a mechanical system representing part of a vehicle. To better investigate the problem of user comfort, more complex models and analyses are needed. In this paper, a model of a real and common vehicle is presented and used, after a calibration process, to perform many dynamic simulations. The obtained results, in terms of weighted vertical acceleration ( aWZ , that is, the WBV index, according to ISO standard), show good correlation...

Good ride quality is a fundamental requirement for all road networks in modern countries. For this purpose, it is essential to monitor and evaluate the effect of irregularities on road pavement surfaces. In the last few decades, many roughness indices have been proposed, with the aim to represent shortly the pavement surface characteristics and the relative performances, using a single number and a correspondent scale of values. In this work, a comparison between three different evaluation methods (International Roughness Index, ISO 8608 road profile classification and frequency-weighted vertical acceleration a_wz according to ISO 2631) was carried out, applying these methods to some real road profiles. The similarities and differences between the obtained results are described, evaluating the effect of the road characteristic speed on the roughness thresholds. In fact, the specific aim of the analyses is to underline the need to use different thresholds depending on the speed at which the vehicular traffic can travel on the road sections. In this way, it will be possible to identify appropriate thresholds for the various types of roads, having for each of them a specific range of design or operating speed.

This work calculates and discusses the Life Cycle Assessment (LCA) of four scenarios composed of two types of road pavements and two types of lighting systems to be built in an Italian twin-tube road tunnel. A 20-year time horizon is adopted to assess the burdens of construction and maintenance of both flexible and rigid pavements and high-pressure sodium (HPS) and light-emitting diode (LED) lamps, traffic, and switching on of lamps. All considered scenarios are comparable with each other in terms of technical performances, but significantly differ regarding their environmental consequences. The geometrical and technical characteristics of the examined scenarios comply with current Italian standards for highways. In all the examined cases, LCA is carried out according to the European standard, EN 15804, and includes 19 impact categories (IC). The analysis demonstrates that the use of more reflecting surface pavement materials (i.e., concrete vs. asphalt) and more performing lighting systems (i.e., LED vs. HPS) can effectively mitigate the deleterious burdens related to road construction, maintenance, and use. For most of the examined ICs, the most environment-friendly scenario has LED lamps and concrete pavement.