# Road Pavement, Road Pollution, and Sustainability under Climate Change Increased Temperature
## 1 Introduction
### Climate Change Impacts on Road Pavement and Road Runoff
\begin{table}
\begin{tabular}{l l} \hline
**Extreme Occurrences** & \multicolumn{2}{c}{**Relevant Effects on Road Pavements**} \\ \hline  & \(-\) & Flexible pavements experience a higher occurrence of rutting \\  & \(-\) & Bituminous pavements display signs of bleeding \\ Temperature top range are increased & \(-\) & Bituminous layers undergo accelerated aging \\  & \(-\) & Higher demand for maintenance \\  & \(-\) & Higher risk of occurrence of bushfires \\ \hline  & \(-\) & The bearing capacity decreases \\ Decreased temperatures and augmented freeze–thaw & \(-\) & Bituminous pavements may suffer from cracking, raveling, \\ occurrences & \(-\) & the formation of potholes \\  & \(-\) & The demand for pavement maintenance, including \\ \hline  & \(-\) & Water levels tend to rise \\  & \(-\) & Road drainage systems may become inadequate, resulting \\  & \(-\) & In flooding \\ Higher frequency of storms and higher rainfall intensity & \(-\) & The bearing capacity is diminished \\  & \(-\) & Cracking and permanent deformation may occur \\  & \(-\) & Higher risk of slope failure \\  & \(-\) & Risk of road closure and loss of efficiency in the \\  & \(-\) & transportation service \\ \hline  & \(-\) & Surface roughness increases \\ Increase in droughts & \(-\) & Subgrade moisture tend to decrease \\  & \(-\) & Issues related to salinity arise \\ \hline \end{tabular}
\end{table} 
Table 1: Relevant effects of climate change extremes on road pavements. tions. A recent study by [PERSON] and [PERSON] [17] estimated the increase in operation and maintenance costs (O&M) of railway and road infrastructures across the 27 Member States of the EU and the United Kingdom, based on climate projections under RCP4.5 and RCP8.5. The authors concluded that under a 4 \({}^{\circ}\)C global warming level, increased levels of extreme heat would cause annual transport O&M costs to rise by \(\xi\)4.8 billion, corresponding to an overall 6.9% rise compared to current values. Some studies dedicated to the impacts of climate change regarding pavement maintenance are mainly focusing on pavement materials and maintenance costs, and the conclusions are based on modeling tools [18; 19]. On the other hand, when evaluating road runoff, specialists are concerned with the transport and discharge of increased water volumes and increased flow rates during runoff events caused by extreme precipitation (e.g., [20; 21; 22; 23; 24]). While precipitation is clearly a critical issue of concern, temperature, expected to change as well, is not addressed much; although, it has already been correlated with the presence and concentration of pollutants (e.g., [25]). [PERSON] et al. [26] note that asphalt concrete road pavement is sensitive to ambient temperature variations which, together with mechanical impact from vehicle load leads to several damages and material deformations. The thermodynamic behavior of road pavement, as well as the reliability and durability of different mixtures, are of great importance and a concern for research and practice [27; 28]. Flexible pavements, under current climate conditions, can reach temperatures between 40 \({}^{\circ}\)C and 50 \({}^{\circ}\)C in Southern Europe [29]. Therefore, under future climate conditions higher pavement temperatures are expected. It has been pointed out (e.g., [30]) that road pavement softening at elevated ambient temperature may be likely to aggregate particles accumulated at the surface, therefore, acting as a sink of pollutants and contributing to pollution retention and environmental protection.