Youngsters at the BMX track at Porth in Rhondda Cynon Taf said it has given them "something to do" - and is "great fun."
The initiative has been picked out as one of the best in Europe for crime prevention.
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Dull and damp for much of Wales as we start the day, with drier and brighter weather on the way this afternoon.
The heaviest of the rain will ease overnight. Remaining mild but breezy around coastal areas.
Every time you give blood, you save a life. And for 70 years, more than 10 million units of blood have been donated in Wales.