USATF Road Race Course Measurement Accuracy
by Brian Cavanagh, USATF Certified Coach

How do you drop your 10km time from 45 minutes to 38 minutes in a year? Here's one story.

I was 37 years old,
had dropped my 10km times from 45 to 41:30 from August of 1992 to July of 1993. I had run higher mileage and mountain races in 1992 to develop a solid foundation of cardiovascular and muscular endurance. I was training hard with a good mix of speedwork and resting appropriately. An enticing sub 40 by the end of the summer looked possible. Having run 35:51 for 10km in 1984 (and 27:41 for 8km in 1979), I wanted to get back to that feeling of strength and power that comes from a sense of mastery over one's own body: the feeling of being able to "turn up the throttle and rev the engines", to push my own limits and feel that I still had more power. That's what I loved about racing when I was well-prepared.

In late August of 1993, I ran an 18:33 for 5km (down from 20:44 in January 1993), then in early September, I ran a 38:07 for 10km! I was psyched because I ran hard and felt that maybe this 38:07 was my breakthrough race. I had brought my bike to that
race to measure the course since I wished I had done so for the 18:33 the week before. (The 5k was accurately measured by an expert, I later learned.) I rode the bike on the "10k" course afterward, finding out that the course was not even 10km  (6.2137 miles). It was 6.07 miles! That meant that the supposed 38:07 would have been a 39:01 if the course had been the correct length. It was still a breakthrough race, but why would a long-time experienced race director and runner put on a race that was a full minute short over 10km? The local runners raved about what a great fast course and good time the race was. There was a festive atmosphere, good food and camaraderie there. How could the course be so short?

Surprisingly fast road race times are often the result of inaccurate courses, although many runners would like to believe that they simply ran well.
USATF (USA Track and Field) has special procedures which a few of us in the Sullivan Striders and Orange Runners Club have been applying to make more courses in the region accurate. RRCA (Road Runners Clubs of America) has adopted the same standard, as have the international marathon race directors, World and Olympic Championships. The procedures are the result of years of experience in all weather conditions and running surfaces, on every type of course imaginable. Hundreds of articles have been written on the topic of
USATF road race measurement procedure.

Many runners are unaware of the role which course accuracy plays in their sport. I was one of them from 1974 to 1989 until Pete Mazeiko of the Orange Runners Club explained what a Jones-Oerth device is and how it is far better than a regular bike odometer. Here are some drawings of a Jones-Oerth device:
Jones-Oerth device drawings

Pete, 
Frank Giannino and Kurt Krauss did much of the expert course measurement work in Sullivan and Orange Counties in the 1980's and early 1990's, with Frank achieving the USATF standard of certification for more courses than anybody. In 2001 and 2002, Brian Cavanagh and Steve Holmbraker led the way on course measurement, assisted by Ed Homenick, Kathleen Rifkin, Bob Harris, Bill Norton, Pete Anzevino, Barry Shavrick and Zac Shavrick. Through collaborative efforts and planning in 2001 and 2002, they accurately measured more than thirty courses in Sullivan and Orange Counties. Race course distances varied from 5km (3.106856 miles) to 100km (62.13712 miles). The 100km is only the sixteenth USATF Certified race of its length in the United States.

We have found that the majority of road race courses in the region are NOT accurate. We have heard runners grumble about a course being "long" when it is accurate; because the other races they had been doing were short, their frame of reference was skewed. This reminded me of the high school football players who bragged that they had run "the mile" in sub 6 minutes: they ran five laps around the football field. There was no track. When my HS track distance runners ran the same five laps around the football field in gym class, even the slowest guy on my team (a 2:48 half-miler) ran a 4:48, several guys ran well under the league record of 4:21, a few even breaking the magic 4 minute mile barrier for high school students which had only been broken once before by Jim Ryan and Marty Liquori. My fastest guy even broke the World Record by running a 3:38 ! It took some explaining to convince my track team optimists they hadn't run a full mile. Postscript: the "3:38 miler" eventually ran a 5:11 for the mile (when he was in far better shape) on an accurate track that season. While the differences are usually not as exaggerated in road racing in the region, the differences between accurate and inaccurate can range from subtle to obvious. More race directors should have their courses accurately measured using USATF course measurement procedures. If they say it's a 5km, it should be a 5km (3.106856 miles). It's a simple matter of using truth in advertising.

USATF course measurement procedures are designed to insure that the actual distance for a race is at least the advertised distance, meaning "not short"; by USATF standards, it should be accurate to within one tenth of one percent when compared to a known accurate course. Over the span of 5km (16,404 feet), that would be about 16 feet. USATF certified courses also have a one tenth of one percent correction factor added (ie. 1 meter added per 1,000 meters) to insure that they are not short. The correction factor that is added to a 5km is 16.4 feet (5 meters).

The two most essential steps for accurate course measurement are:
  1. First, use the Jones-Oerth device on the calibration course, then
  2. Second,measure the road race course with the Jones-Oerth device.

Shouldn't the times you run in races accurately reflect your level of fitness?

Yes! While the experience of running two different courses is never identical in terms of hills, number of turns, weather conditions (such as wind), and how you feel that day, the distance of the two courses should be comparable to a known accurate course. In USATF lingo, a known accurate course is called a calibration course.

The first step that we take in measuring a road race course accurately is to establish an accurate calibration course. The level of detail required is visible in the USATF-approved paperwork below. This course is measured by using a series of surveyor's steel tape measurement lengths and then adding or subtracting distance by using a math formula which takes into account the effect of temperature on expansion or contraction of the steel tape. Fiberglass tape measurement is not acceptable because the tape stretches inconsistently. Nails are driven into the roadway to permanently mark the location of the calibration course, a detailed map is drawn, then the map and an application (below) are submitted to USATF. Amy Morss, an experienced certifier with USATF, examines the math, the map and the application for all New York State courses to see if procedures were followed correctly. If they were, a certificate of accuracy is given along with a USATF Course Certification number. The course is then called a USATF Certified Course. The following is an example of one: USATF Certified Course #NY01046AM. This code is for a race in New York State ("NY") which was approved as accurate in 2001 ("01"), and was the 46th course of 2001 ("46") that was certified by Amy Morss ("AM") of USATF as accurate.

The second step in course measurement involves laying out a road race course. This is where it helps to have the expertise of previous race directors. RRCA and USATF have lots of information on their websites which you can read to learn how to measure courses, and local measurers (above) can be hired. Laying out a course means deciding where it will go, making sure that there is enough room to adjust the start and / or finish to make it accurate after actual  measurements are done. It is not possible to decide in advance exactly where the start AND finish lines will be. However, their locations can be approximated during the layout process.

The third step is measuring a road race course. Courses should be measured from finish to start because finish line area details are usually more complex and the finish line needs to be established before the start line is precisely located.

To measure a road race course, we do not use a bike or car odometer. Instead, we use a highly accurate device called a Jones-Oerth device. This is a mechanical counter that mounts on the front wheel of a bicycle and shows a series of digits in a row, just like a car odometer reading. Each digit it registers represents only a fraction of a bicycle wheel revolution, so we call this "high resolution" measurement: it is very sensitive. One bike wheel revolution may increment the Jones-Oerth counter 3-4 counts. Since the number of counts that the device registers varies according to the wheel diameter, we will see how many counts it takes to ride a known accurate course (calibration course).

For example, if the Jones-Oerth device registers 4,000 counts on a 400 meter calibration course, then we do the math and figure that it must be registering 10 counts per meter that day (4,000 divided by 400 equals 10). Further calculating tells us that we would need to show at least 10 times 5000 (50,000) counts if we were to measure out the appropriate distance for a 5000 meter race.  (5000 meters is the same as 5km.) Because there is always a margin of error when measuring, USATF requires that 1 meter per km (5 meters in this case) be added onto the course, or 50 more counts on the Jones-Oerth device. Therefore, when measuring from finish to start along the intended road race course, the Jones-Oerth device should register 50,050 counts on those days when we get 4,000 counts per 400 meter calibration course ride.

What makes the use of the Jones-Oerth device significantly different from a bike or car odometer is that the Jones-Oerth device has to be calibrated every day that it is used or else it is worthless. This allows the Jones-Oerth device to usually register more counts on a 400 meter course on a cool day than it would on a hot day. On a hot day, the bicycle tires expand enough to increase the wheel diameter (and consequently the circumference, the distance of one wheel revolution). This causes the Jones-Oerth device to register fewer counts per 400 meters on those hot days. The amount of air pressure in the tires, a high pressure or low pressure weather system, direct sun, cloudiness, and road temperature will all affect the number of counts which the Jones-Oerth device registers that day on the calibration course. The weight of the rider and his or her equipment on the bike will also affect the number of counts which the Jones-Oerth device registers.

Contact Steve Holmbraker of the Orange Runners Club, or Brian Cavanagh of the Sullivan Striders (see phone number below) if you would like to obtain a Jones-Oerth device, learn how to measure road race courses, or would like to have them measure a course for you.


Below is a sample application for certification of a calibration course by USATF (USA Track and Field. The calibration course is 400 meters long, is on Airport Rd in the town of Bethel, and was measured by using a series of surveyor's steel tape measure lengths.

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APPLICATION FOR CERTIFICATION OF CALIBRATION COURSE

1. Name of Calibration Course _________Airport Rd 400M________________________

2. Length of Calibration Course ______________400 Meters______________________

3. City and State _______Bethel, NY (USGS Quad: White Lake ) ___________________

4. Date(s) Measured _________7/18/02________________________

5. Method Used to Measure Calibration Course ______steel tape taping method____________

6. How many times did you measure the calibration course? twice by tape, pre-measured ("roughed out") by calibrated bike four times

7. Measuring Team Leader: ____Brian Cavanagh______ , ___________845-791-6149_____
                    (name)                     (telephone #)
 _____9 Lake Shore Drive West, Rock Hill, NY 12775_________________
            (address, zip)    

8. List Names and Duties of Team Members: Supervision, teaching (by demonstration), reference measurements & note-taking: Brian Cavanagh; Barry Shavrick- lead tape person, reference measurements; Zac Shavrick- rear tape person

9. Submit a map of this calibration course, showing direction of north, the name of the road (and relevant cross streets), and the exact locations of start and finish points, including taped distances from nearby permanent landmarks.

10. Is this calibration course: STRAIGHT? __yes_________ PAVED? ____yes______

11. How are the start and finish points marked? PK nails, pink survey ribbon in pavement on inner edge of white line demarcating shoulder of road, white line on paved shoulder of road perpendicular to lane line.

12. Are the start and finish points located in the road where a bicycle wheel can touch them?_yes_

13. Approximate altitude of calibration course: _1280 ft_

Mark endpoints in a permanent way (concrete or P-K nails). Paint will fade. The calibration course, once certified, can be used to measure many courses.

14. If the calibration course was measured by Electronic Distance Meter (EDM), describe on a separate sheet the exact procedures used; also include a copy of the original field notes from the measurement.

15. If the calibration course was measured by steel tape, fill out a copy of the steel taping data sheet and complete the following:

16. How much tension (force) was applied to the tape while measuring? ___11 pounds___

17. How was this tension maintained? spring scale

18. Was the tape free of any kinks, crimps or splices? _____yes___________

19. Bicycle Check. This is a check against miscounting the number of tape lengths. (If you used a gross measurement check other than a bicycle, please explain.)

Gross check: 400 meter course pre-measured ("roughed out") by calibrated bike four times prior to taping.


STEEL TAPING DATA SHEET
(for measuring a calibration course or track)

Name of Calibration Course_______Airport Rd 400M__________________________

City and State___Bethel, NY___________________ Date _____7/18/02__________

Start Time __8:20am_______ Finish Time ____11:20am_______

Pavement Temperature: Start ___78F__ Finish___88F_ Average __83F___
(Thermometer shaded from direct sun)

Measurements and Calculations:
1. First Measurement. This establishes tentative start and finish marks which should not be changed until the final adjustment on line 6 below.

( ____6___  X ____200 ft_____ ) + ____112.34 ft_____ = ___________1312.34 ft________
    # tape     distance per         partial tape             measured distance
    lengths     tape length            length

2. Second Measurement. This checks the distance between the SAME tentative start and finish points marked in the first measurement, but use new intermediate taping points.
( ____6____  X ____200 ft_____) + ___112.235 ft_________ = _______1312.235 ft__________
    # tape     distance per         partial tape             measured distance
    lengths     tape length            length

3. Average Raw (uncorrected) Measurement of Course _________1312.2875 ft________

4. Temperature Correction. Use the average pavement temperature during measurement in whichever formula is appropriate (for Celsius or Fahrenheit temperature). Work out answer to at least seven digits beyond the decimal point.

Correction factor = 1.0000000 + ( .00000645  X [Temp(F) – 68] )
Correction factor = 1.0000000 + ( .00000645  X [83 – 68] )
Correction factor = 1.0000000 + ( .00000645  X 15 )
Correction factor = 1.0000000 + ( .00009675 )
Correction factor = 1.00009675

NOTE: For temperatures below 20 C (68 F), factor is less than one
For temperatures above 20 C (68 F), factor is greater than one

5. Multiply the temperature correction factor by the average raw measurement of the course (line 3)

____1.00009675___  X ______1312.2875 ft_________ = _____1312.4145 ft_________
    correction factor         avg. raw measurement         corrected measurement

6. If you wish, you may now adjust the course to obtain an even distance, such as one kilometer (not applicable if measuring a track). This is not necessary as you may choose instead to use an odd-distance calibration course whose endpoints are pre-existing permanent objects in the road to guard against hazards such as repaving. If you adjusted the course, explain what you did.

Note: We shortened above course by 0.07 ft to make it 1312.34ft, or 400.003 meters.     
400 meters is 1312.336 ft.

Final Adjusted Length of Calibration Course ___________1312.34 ft______________________


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