Complex sentence: In 2003, Caltrans published a map showing potential improvements to the transportation infrastructure of southern California, the proposal showed both the un-constructed portion of Route 14, as well as new routes over or under the mountains to Antelope Valley.
Split into simpler sentences: In 2003, Caltrans published a map showing potential improvements to the transportation infrastructure of southern California. The proposal showed both the un-constructed portion of Route 14, as well as new routes over or under the mountains to Antelope Valley.