Erio Tosatti, former ICTP Acting Director and a Condensed Matter theorist at ICTP and SISSA, has published an article in the December edition of Nature Materials, exploring why cars tend to slip on wet roads.
We all know that wet roads are dangerous roads. In fact, most of us have been terrified by the experience. But scientists have never been able to devise a convincing quantitative explanation as to why this occurs. Tosatti and his colleagues have shown, through a series of simple but illuminating calculations, that wet road surfaces created during and after rainstorms yield a 20-percent reduction in friction, matching in theory what has been obseved in practice. In scientific terms, by making the surface effectively less rough, water on wet roads reduces the tires’ deformation and decreases the viscoelastic damping of the mechanical energy in the rubber. Simply put, the results can be harrowing. For additional information, see Nature Materials, doi:10.1038/nmat1255.
See also ABC News.