Complex sentence: It was proposed to be completed by the end of the summer in that year, to help commuters to New York City and the authorization to be proposed for subways in the city by the state of New Jersey.
Split into simpler sentences: It was proposed to be completed by the end of the summer in that year, to help commuters to New York City. The same proposal asked for authorization of a proposal for subways in the city by the state of New Jersey.