Complex sentence: In 2011, the Bakersfield Park District opened Mesa Marin Sports Complex on the site where the raceway had stood, which as of 2015 includes four ASA/USSSA regulation softball fields and is zoned for more facilities to be added at a later date.
Split into simpler sentences: In 2011, the Bakersfield Park District opened Mesa Marin Sports Complex on the site where the raceway had stood. As of 2015 the complex includes four ASA/USSSA regulation softball fields and is zoned for more facilities to be added at a later date.