http://www.dmv.state.pa.us/pdotforms.../chapter35.pdf

Chap. 35
Sub. Chap. A
Sec. 4
Sub. Sec. (b) -No pedalcycle shall be used to carry more persons at one time than the number for which the pedalcycle is designed and equipped except that an adult rider may transport a child in a pedalcycle child carrier which is securely attached to the pedalcycle or in a trailer which is towed by a pedalcycle.

Pennsylvania's 'bike passing' law, is four feet.

But, Despite the creation of the 'passing' laws, as was mentioned in another thread about the bias, that law enforcement and the judicial system continually display. Finding in favor of the motorist, and finding fault with the cyclist. Albeit indirect, this is just another example of authorities continually blaming the cyclist, even when they are in the right.