Now remember this was back in the early 1900's not everyone had a vehicle and in fact horses where still being used for delivering milk etc.
So it only made sense that this was and back then trolleys went everywhere . You could board a trolley in Pittsburgh and by switching to various trolly lines at one time be able to go all the way to Cleveland , Detroit even Chicago by trolley and rail line. Some trolley lines even carried freight and even had special ambulance cars which got people to hospitals.
Several other community's which had trolleys also are suppose to have had this law on there books as well.
You can view more carrick trolley pictures and even read articles I wrote on them as part of my Eagle scout project on history of carrick at following link.
But Pittsburgh Railways which ran the big net work of trolleys before it was taken over by Allegheny county Transit authority known as PAT Port authority transit. Still exists and was a one time big player in the Alarm Business . They are still known today as Pittway that's right the people who bought and expanded ADEMCO Alarm systems till they sold out to Honeywell.