Of the common types of surfaces in modern cities, there is a 4 dB  difference between the loudest and the softest: chip seal type and grooved roads being the loudest, and concrete surfaces without spacers being the quietest, and asphaltic surfaces being about average.
Among the typical types of surfaces in contemporary urban areas, there is a 4 dB difference between the loudest and quietest: chip seal type and grooved roads are the most boisterous, while concrete surfaces without spacers are the quietest, with asphaltic surfaces falling somewhere in between.