The ASC (Anti-Skid Control) light comes on when one front wheel is rotating faster than the other front wheel. This usually occurs when accelerating on a slippy surface. In your case if it is happening on a dry road and in a straight line then it is probably a wheel speed sensor that is intermittently failing. This will also affect the ABS system. Only way to find out which sensor is to plug it into a diagnostic box.
BTW, if you disable ASC using the switch does the ASC light stay on all the time and the problem go away?