Curved Ramps are the most simple of ramps. They are simply elevated, metal ramps that can force a player's car into the air. Instead of a straight incline they are curved upwards, ever so slightly, to launch the vehicle higher than a Straight Ramp. They are not useful as Split Ramps for stunts, but instead they are far more useful for reaching certain shortcuts and other areas such as the railroads in Harbor Town and Downtown Paradise that are built above the roads and the I-88.
In stunt run events, curved ramps' effectiveness is very similar to Makeshift Ramps. They are usually used simply for Air Time. There is no way to safely start a Barrel Roll and complete it because they do not have the uneven sections like the Split Ramps. They can be used, however, for Flat Spins if the ramp is elevated enough.
Curved Ramps find their usefulness more so in events besides Stunt Run. The Curved Ramp is enough to elevate the player's vehicle high enough to perform a vertical takedown easily and puts the player in little or no risk (unlike the Split Ramps' Barrel Rolling tendencies). They are also very useful for reaching certain shortcuts and other areas of the city quickly, as described above.