Just a point of clarification, Ken says "this summer" the linked page says "spring and fall" with details of
Offer available for a limited time, motorcycle tickets are free* with a paid passenger fare.
- All trips (one-way and roundtrips) - Spring (May 1-May 31) and Fall (September 2-November 2, 2014)
- Roundtrip motorcycles ride free in June (standard fare applies to one-way motorcycle tickets)
Which excludes a lot of the summer.