Green’s Dictionary of Slang

(US) cruising the streets in a low-slung, customized car.

2000

Hip-Hop Connection Jan./Feb. 54: Lowriding. [...] They prefer to modify the suspension on their motors so that the car is much closer to the ground. Because of the illegality (and/or stupidity) of driving this way, the cars are further modified with hydraulic systems that make them bounce.