We sometimes receive queries from runners or officials who have doubts as to whether a race length is correct. If there is clear evidence of the exact route that was used on race day, the area measurement secretary can compare the course as run with the measurer's report. In other cases the AUKCM may look for tracks and distances from runners' GPSs. Although GPS tracks are not nearly as accurate as the measurer's bike and often zigzag off the road (or through buildings!) and they differ from one another, as a general rule when the average is taken of several tens of GPS tracks it tends to give a course length slightly longer than the true race distance. So, if the average of a lot of GPS tracks is less than the race distance there is certainly evidence for a short course which needs investigation. Of course it is not only short courses that would be investigated, e.g., if there is evidence that runners followed the wrong route, an investigation might show a long course had been run.
The following reports on investigations are online here:
Newham Classic 10k run on 15 April 2012
Hull Marathon run on 8 April 2012
Hampton Court Half Marathon 23 February 2014
Manchester Marathon 2013-2015
St Helens 10k on 6 March 2016
Trafford 10k on 13 Mar 2016
Remeasurements following discovery of a Short Calibration Course, Apr 2016
Procedure for Measuring a Calibration Course
Limitations of GPS for Road Races - views from non-course measurers
Mike Sandford's recording of his description of how courses are measured
Course Measurers will always try to assist with short-notice changes imposed on organisers. If no measurer can be found to make an adjustment, we have guidance for minor adjustment of courses by taping, and will always offer telephone advice.
Race organisers should first contact the original measurer for last minute help, and then if necesssary the Area Measurement Secretary.
Runners should be informed BEFORE the start if there have been changes to the measured route.