Complex sentence: It can only be speculated whether such frequent delays would have been acceptable had the gyrobuses survived-in commercial service-into the modern era, especially on longer routes where several charging stops could have been required or on busy, heavily trafficked roads.
Split into simpler sentences: It can only be speculated whether such frequent delays would have been acceptable had the gyrobuses survived-in commercial service-into the modern era. Especially on longer routes where several charging stops could have been required or on busy, heavily trafficked roads.