INSIDE MOBILE: The Marathon-One of the Largest Mobile RFID Applications

You might think that running a 26.2-mile marathon is about the most difficult human activity. It isn't. Rather, it's keeping track of the places and times for 30,000 or more people that are running (and walking) in the race. I have fortunately run three marathons in my life, with the best one being the Los Angeles Western Hemisphere Marathon on Dec. 10, 1967. This is when I ran 3:23:00 or about 7:45 minutes per mile for 26 miles.

Keeping track of the few thousand crazy runners that day was a nightmare. The race organizers had a long "chute" at the end of the race to hold hundreds of runners in their order of finish. Volunteers would tear off a small strip on their race number that included a duplication of the runner's race ID. The volunteers used a long string with a thick needle to thread each runner's small ID number through a small hole. This allowed them to capture the order of the finish of (almost) everyone.

Recording the time of every runner was much more challenging. It was impossible to have volunteers (even if there were a lot of them) record the time of every runner; there were simply too many runners finishing at one time. Race organizers would, instead, record a runner’s time every 5-10 seconds and write down the runner's number next to their time. Then, the race officials would sit down and go through the long string of runner ID tags and interpolate times for all the runners, based on the ones for which they had recorded a time. This took many hours and the whole process was subject to error. That was 1967.

My wife Alicia and I flew to San Antonio on Nov. 15, 2008 to watch my son Bryan and his significant other Claudia run in, and complete, the Rock ‘n’ Roll San Antonio Marathon. Each runner in all major road races today is given a number (just as always), plus a special tag that has an RFID chip embedded in it—which is most typically attached to the laces in the runner's shoe. Take a look at the photo below. You can see the bright orange tags on the shoes of all the runners.

Note the insert in the photo of what the tag looks like close up. The tag includes a small antenna that can be read by readers placed along the course. Most of us have used a system similar to this in our cars when we have a responder (tag) in the windshield that’s read by turnpike toll readers.

The San Antonio race organizers used an RFID system supplied by ChronoTrack Systems. They set up RFID readers at intervals along the Rock ‘n’ Roll San Antonio course. The readers (shown in the photo below, underneath the mat that lies across the finish line) enabled recording the individual splits for every runner throughout the entire course.

Runners were grouped according to projected finish time in "corrals" of 1,000 people each. The race officially started for the elite runners at 7:30 a.m., which meant many of the volunteers had to be there at 5 a.m. Each corral started at intervals of around 90 seconds. But since there was an RFID reader at the starting line, the system was able to determine the actual start time for each of the thousands of runners.