The IAAF (International Association of Athletics Federations) is the highest governing body in the sport of athletics (which includes track and field). They cover the sport at an international level, which includes the International Olympic Committee.
SUMMARY
The rules for ties are as follows:
lots (n.): The use of objects in making a determination or choice at random.
SOURCE
According to their 2010-2011 competition rules (see page 140/255), ties are handled based on RULE 167:
167.1: If the Judges or the Photo Finish Judges are unable to separate the athletes for any place according to Rules 164.2, 165.15, 165.21 or
165.24 (as may be applicable), the tie shall remain.
164.2: The athletes shall be placed in the order in which any part of their
bodies (i.e. torso, as distinguished from the head, neck, arms, legs,
hands or feet) reaches the vertical plane of the nearer edge of the
finish line as defined above.
165.15: A system which operates automatically at either the start or the finish,
but not at both, shall be considered to produce neither Hand nor Fully
Automatic Times and shall not therefore be used to obtain official
times. In this case, the times read on the image will not, under any
circumstances, be considered as official, but the image may be used
as a valid support in order to determine placings and adjust time
intervals between athletes.
Note: If the timing mechanism is not started by the Starter’s gun, the
time-scale on the image shall indicate this fact automatically.
165.21: In conjunction with the two Assistants, the Chief Photo Finish Judge
shall determine the placing of the athletes and, as a consequence, their
official times. He shall ensure that these results are correctly entered
in or transferred to the competition results system and conveyed to the
Competition Secretary.
165.24: The use of Transponder Timing Systems approved by IAAF in events
held under Rules 230 (races not held completely in the stadium), 240
and 250 is permitted provided that:
- (a) None of the equipment used at the start, along the course or at the
finish line constitutes a significant obstacle or barrier to the
progress of an athlete.
- (b) The weight of the transponder and its housing carried on the
athletes’ uniform, bib or shoe is not significant.
- (c) The System is started by the Starter’s gun or synchronised with
the start signal.
- (d) The System requires no action by an athlete during the
competition, at the finish or at any stage in the result processing.
- (e) The resolution is 1/10th of a second (i.e. it can separate athletes
finishing 1/10th of a second apart). For all races, the time shall
be read to 1/10th of a second and recorded to the whole second.
All read times not ending in zero shall be converted and recorded
to the next longer whole second, e.g. for the Marathon, 2:09:44.3
shall be recorded as 2:09:45.
Note: The official time shall be the time elapsed between the
firing of the starting gun and the athlete reaching the finish line.
However, the time elapsed between an athlete crossing the start
line and the finish line can be made known to him, but will not
be considered an official time.
- (f) Whilst the determination of the finishing order and times may
be considered official, Rules 164.2 and 165.2 may be applied
where necessary.
Note: It is recommended that judges and/or video recording(s)
also be provided to assist in determining the finishing order.
167.2: In determining whether there has been a tie between athletes in different heats for a ranking position according to Rule 166.3(a) or
for a qualifying position for a subsequent round based on time, the
Chief Photo Finish Judge shall consider the actual times recorded by
the athletes to 1/1000th of a second. If it is thus (or according to
167.1) determined that there has been a tie for a ranking position the tie shall be broken by draw. Where there is a tie for a qualifying
position for a subsequent round based on time or place, the tying
athletes shall be placed in the next round or, if that is not
practicable, lots shall be drawn to determine who shall be placed in
the next round.