These buses come in three different designs differing mainly in their size and height .
In April 2008 , GO began operating 43 - foot ( 13.11 m ) Enviro 500 double - decker buses built by British manufacturer Alexander Dennis in the United Kingdom .
These buses come in three different designs differing mainly in GO 's size and height .
In April 2008 , GO began operating 43 - foot ( 13.11 m ) Enviro 500 double - decker buses built by British manufacturer Alexander Dennis in the United Kingdom .