Complex sentence: It was initially planned to be fully completed by 2014, but the economic downturn resulted in a plan to build the project in phases, with the first phase opening a segment between Northern Santa Rosa and Downtown San Rafael in late 2016.
Split into simpler sentences: It was initially planned to be fully completed by 2014, but the economic downturn resulted in a plan to build the project in phases. The first phase will open a segment between Northern Santa Rosa and Downtown San Rafael in late 2016.