If the Shamrock Run is the run that officially starts race season, there’s no doubt that the Foot Traffic Flat Marathon/Half/Quarter/5k is the race that ushers in Summer. Sure, it doesn’t come around until July 4th every year, but let’s face it – summer doesn’t always come in June around here, especially not this year. Some years, the Foot Traffic Flat is a bit hot, as it wraps around Sauvie Island without much shade. However,…