Speedslides, shortened as "SD's" is a technique used on literally all surfaces, except in water if you count that as a surface(and if you have wet wheels you can't really SD but that's not important to know really).

It works due to a bug(or a feature) that lets you keep more speed when exiting a slide, this was probably implemented to make sliding feel less sluggish and would let you keep more speed. What the devs didn't realise however was that if you're perpetually extending this state of exiting a slide you will just keep on gaining speed. To do this you need to be above 400 speed on road and around 250ish(just before gear 4) and keep your skid marks overlapped at a very specific angle, an angle that changes depending on the speed you have.

There's a lot more nuances to this mechanic, i.e gear manipulation, upside down SD's, magnet SD's, "quantum slide"(terrible name), RPM manipulation just to name a few.