How courses Are Measured
Any race that is advertised as being of a specific distance needs to be measured by a BAF graded Course measurer in order to obtain a cerificate of accuracy.
The only acceptable method of measurement is by means of a bicycle fitted with a Jones Counter. This is not strictly speaking a measuring device but a mechanical device that accurately records 20 counts for each revolution of the bicycle wheel.In order to convert these "counts" to distances a course of known distance is needed.
This "Calibration course" as it is known,should be a straight,level road with the distance accurately measured using either a surveyors tape or more accurately by electronic means.Once this course has been set and marked,it can be used over and over again(until the local authority kindly tarmacs over your markers). The calibration course is ridden a minimum of 4 rides and the average count recorded.This then is multiplied by 1.001 to give the "Short Course Prevention Factor" which adds 10 metres on to a 10k or 42 metres to a marathon.Once you have calculated the counts/mile or Kilometre ,any distance or number of counts can easily be converted either way.
The course as suggested by the race organiser is then ridden and adjustments made to the length before a second(or more) ride to place mile markers and check the first ride.The measurer will ride the line that the runners are expected to take which includes crossing to the right of the road if runners are permitted.The line taken around right hand bends and any restriction on the part of the road to be used will form part of the measurers report.
After the course has been measured,the calibration course is ridden again to check if there are any variations. Temperature and tyre pressure can affect the reading significantly and a solid tyre will reduce the variations caused by these factors.
I measure races within a reasonable distance of Leeds.I can also supply information on any measurer in the North of England AA area.For other areas contact your race permit secretary