N.J. Admin. Code § 13:71-8.30
At each race or performance against time there shall be at least one timer in the judges' or timers' stand. He shall sign the judges' book for each race or performance against time verifying the correctness of the record. All times shall be announced and recorded in fifths of seconds. An approved electronic or electric timing device must be used. If at any time the electronic or electric timing device should fail, the decision of the manual timer as to the time of the heat or dash shall be official.
The timer shall be in the stand 15 minutes before the first heat or dash is to be contested. He shall start his watch when the first horse leaves the point from which the distance of the race is measured. The time of the leading horse at the quarter, half, three-quarters and the finish shall be taken. If odd distances are raced, the fractions shall be noted accordingly.
N.J. Admin. Code § 13:71-8.30