Florida Road Sounds Compilation (Jacksonville Area) 

This is a collection of road sounds recorded from my drives to Jacksonville over the span of an entire year. This mostly features that iconic metallic droning sound that bridges in Florida make.
The sound is explained by grooves cut into the bridge's pavement surface perpendicular to the direction of travel, with their spacing "scrambled" in a sort of semi-random fashion. This sound can also be heard in other states such as Alabama, South Carolina, Hawaii, Illinois, Wisconsin, New Jersey, Louisiana, California, and others. This sound is not to be mistaken with the ones common in Indiana, Pennsylvania, Delaware, and Ohio, as they have completely different groove spacing methods, with slightly different harmonic properties to their sounds. These sounds share a common very low missing fundamental frequency (176 Hz, or F3, at 60 MPH), a missing second harmonic/overtone, but a very prominent third and fourth harmonic, creating a prominent perfect fourth interval. There are more partials/overtones to this sound, especially in FL pavement which has pronounced 6th and 8th harmonics, which gives it the distinct metallic sound.
FDOT specification on their groove spacing:
Cut grooves into the hardened concrete using a mechanical saw device which will leave grooves nominally 1/8 inch wide and 3/16 inch deep. Space the grooves apart in random spacing center of grooves in the following sequence: 3/4 inch, 1-1/8 inch, 5/8 inch, 1 inch, 5/8 inch, 1-1/8 inch, 3/4 inch in 6 inch repetitions across the width to be grooved in one pass of the mechanical saw device. One 6 inch sequence may be adjusted by 1/4 sequence increments to accommodate various cutting head widths provided the general pattern is carried out. The tolerance for the width of the grooves is plus 1/16 inch to minus 0 inch and the tolerance for the depth of grooves is plus or minus 1/16 inch. The tolerance for the spacing of the grooves is plus or minus 1/16 inch.
A clear distinction to make is that FDOT uses the (saw) BLADING method of grooving, NOT TINING. TINING IS A SPECIFIC METHOD OF GROOVING, JUST LIKE BLADING!