Complex sentence: In the United States, during the 19th century, the first streetcar lines developed from city stagecoach lines that were developed into omnibus lines that picked up and dropped off passengers on a regular route and without the need to be pre-hired.
Split into simpler sentences: In the United States, during the 19th century, one of the earliest form of public transit to develop was the omnibus. These were local version of the stagecoach lines that that picked up and dropped off passengers on a regular route and without the need to be pre-hired.