To counter this, a cant (superelevation) is used. The track superelevation was increased to support higher speeds. The allowed unbalanced superelevation will cause trains to run with normal flange contact. Spiral transitions decrease crashes, and insufficient superelevation increases crashes. Banking the track is known as "cant" or "superelevation". Track unbalanced superelevation in the U.S. is restricted to , though is permissible by waiver. The M10 ballistic drive is upgraded with a fully electrical superelevation resolver. Additional controls are used to correct the slope, crown or superelevation of the finished pavement. The shooter then pulls the trigger fully, and immediately applies lead and superelevation. The amount of superelevation increases with its design speed and with curve sharpness. A given amount of superelevation is most effective over a limited range of speeds. This is called superelevation or cant. Insufficient superelevation will also result in an increase in crash rate. Raising superelevation may be considered for sharp curves which significantly limit speed.