Timing Frequently Asked Questions
Note that our FAQ focuses on general timing technology and methods. For questions about our services, see Services.
What are the most common timing methods?
Today the three most common timing methods are: chip timing, photo finish timing, and pull-tag timing.. Briefly we’ll review each one:
- Chip timing, also known as RFID timing or transponder timing, is generally the best method of timing for recreational road races. Participants wear Radio Frequency Identification (RFID) tags programmed with unique numbers attached to their bib, on their shoe, or attached to their ankle. Timing points at the finish, start, and intermediary split points are setup with antennas that omit and listen for electromagnetic waves at certain frequencies. The antennas can be either embedded in mats, placed underneath ramps, mounted to the side, or on overhead trusses. As participants cross a timing point their RFID tag harvests the electromagnetic energy from the antennas, powers up a tiny integrated circuit in the tag, and responds with the tag’s unique number. The antennas hear the unique number and send it to an RFID reader which records the time and unique number. All of this happens in a fraction of a second. Properly setup and operated chip timing system can be highly accurate, fully redundant, and reduce the burden of work on both race officials and participants.
- Photo finish timing also known as fully automatic timing ("FAT") with line scan cameras or vertical slit cameras is used frequently in track and field although it is also used in elite road races, major XC races, motorsports, cycling, and horse racing. Photo finish timing is done by specialized cameras typically setup at both ends of the finish line. The cameras operate at extremely high frame rates (the fastest cameras operate at 10,000 frames per second; by comparison HDTV is only 60 frames per second). The cameras only take photos of a narrow vertical slice of the finish line. The images are then merged together and the timers using specialized software click on the point where the leading edge of the athlete’s torso is. This point is then matched with the photo it is from and that photo’s timestamp becomes the finisher’s time. In major road races typically the elite field are timed with FAT systems and the remainder of runners are timed with the chip systems unless a dispute arises or the chip system fails. The downside to FAT systems is they are labor intensive and slow to produce results. A timer has to carefully review each finish, read the hip number, click on the leading edge of the torso, and input that number.
- Pull-tag timing or hand timing consists of participants wearing a bib with a perforated tag printed with their bib number. As the participant crosses the finish line a timing operator presses a button on a device which stores a list of finish times. After the participant finishes a person collects the perforated pull-tag attached to the participant bib and places on a stringer in the order of the finish (the pull-tag collector is at the end of a finish chute, which is why it's important to stay in your finish order as you move through the finish chute). At the end of the race the stringer contains the number of every finisher in the order they finished and the timing device contains every finish time in the order recorded. The ordered list of finish times and ordered list of finishers is than merged to produce results. In most pull-tag races the merging of the times and finishers is done multiple times during the race so results are available soon after the race ends. To reduce the likelihood of errors, timers using pull tags often input as many bib #s as they can as the athletes finish. These bibs numbers known as select or spot times help identify any discrepancies in the finish order from the stringer. For small races with experienced timers and experienced participants accuracy of pull-tag timing can be very good. We don't see pull-tag timing a lot any more in Oregon but in other parts of the country it's more common and it can be very accurate.
Why did UHF RFID timing become so popular for road racing?
There are quite a few reasons, but one of the biggest driver in its adoption was the widespread adoption and standardization of Ultra High Frequency (UHF) RFID by other industries. Other industries have considerable commercial interests in automating the tracking of goods and products. That interest in 2005 lead to a remarkable global standard for tracking goods using UHF RFID (the standard is known as EPCGlobal Gen 2 Class 1). The standardization has resulted in a wide availability of UHF RFID components along with reduced component costs (the component costs has been further reduced by the proliferation of cell phones whose radio components are often shared with UHF RFID readers).
Race timers took notice and since 2008 multiple UHF RFID race timing solutions have been introduced and continue to be introduced. The advantage to these solutions over Low Frequency (LF) RFID, such as ChampionChip which was very popular prior to 2010, include:
- Disposable tags. The costs of UHF tags is significantly reduced over plastic LF tags, such as ChampionChip, such that the tags can be considered disposable and the race no longer has the burden of collecting chips at the finish line.
- Chips integrated with the bib. UHF RFID allows for greater read distance which allows for the chip to be placed on the back of the participant's bib. Thus the participant doesn't have to follow explicit instructions for placing a tag on their shoe or ankle.
- Increased read speed. UHF RFID can read tags faster. The high read speed generally translates into higher participant read rate; meaning it's less likely the system misses a participant.
- Greater selection of components. Because of the considerable commercial interest in UHF RFID in other industries there are numerous UHF readers, tags, and antennas that can be chosen from.
Why are there multiple mats or overhead trusses at the start and finish lines, and which one is the actual start and finish line?
Each mat or overhead truss with antennas represents a read zone. Multiple read zones are typically placed at the start and finish lines in case the first read zone fails to read your chip or the computer system attached to that read zone fails. The actual start and finish lines are typically the first read zones you encounter at the start\finish and in the majority of cases these first read zones read your chip. Note that you may also notice a read zone approximately 40 feet prior to the actual finish. This is used to provide race announcers with participants approaching the finish line and is becoming increasingly common.
I’ve heard that larger races like the Boston Marathon have a random, unannounced timing point called a “cheater line.” What is this?
To ensure that all participants have ran the entire course large marathons will randomly place one or more timing points on the course. This is done in addition to the timing points at published split points, so that an athlete could not just drive to all split points and then cross the finish line. The timing equipment at the “cheater lines” is usually fairly sophisticated with double read zones and select timers, so that equipment malfunction does not cause an erroneous disqualification.
Why do chip-on-the-bib tags have a foam spacer behind the RFID tag?
Ultra High Frequency RFID performs poorly near water. To prevent the water in a human body from absorbing the UHF signals a small, typically 3 to 6mm, foam spacer is placed behind the RFID tag. Races can be timed without the spacer but the risk of the system missing a runner in increased.
I am missing from the results or there is an error in my result. What should I do?
Immediately email the race or timers. Usually contact information is on the race results. The timers will typically look through video finish of the race to find your time or in a pull-tag race review the pull-tag stringer. It is important to always notify the race or timers if there is an error as the information helps improve the timing process and avoid future issues.