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.
The range of surface types found in modern cities exhibits a 4 dB variation between the noisiest and quietest: chip seal type and grooved roads stand out as the most vocal, whereas concrete surfaces without spacers are the least noisy, with asphaltic surfaces occupying an intermediate position.