An access control apparatus for use with a disc drive having a head provided for movement with respect to tracks on a disc to produce a reproduced signal containing a data signal. The access control apparatus includes a drive device for moving the head in a direction radially of the disc to perform rapid access from one track to a desired track. A traverse detector is provided for producing traverse detection pulses in response to the data signal. The traverse detector includes a trigger signal generator responsive to the data signal for producing trigger pulses for respective cycles of the data signal having a magnitude greater than a predetermined value and a timer responsive to each of the trigger pulses for changing to a first state. The timer returns to a second state a predetermined time afer each the trigger pulse occurs. A counter counts the traverse detection pulses to accumulate a count corresponding to the number of tracks traversed by the head. The drive device is controlled in accordance with the count of the counter.