Back in the good old days of BOAC the rejected take-off was certified and checked under the criteria that one allowed the pilot one second to recognise the situation and make his decision and a further one second for each manipulation required.
Assuming therefore a failure exactly at V1 on an older type of 747, the aircraft would travel a considerable distance before effectively decelerating, during which the pilot would have recognised/decided to abandon take-off, closed the throttles, applied full brakes, deployed the speedbrakes and selected full reverse - a total of 5 seconds.
Are modern aircraft so certified?