100 meters to what or from ?

We came across these signs while out walking this morning and there was no information at to what it was 100 meters too! Was it a race ?. If so for runners, cyclist or vehicles ? and had it took place yesterday or was it on today ?

In the end we ended up in giggles and I even persuaded Mrs M to pose (She does not like her picture taken). What ever it was or had been had brighten up our morning!!