It was watching the empty buses leave in the dark outside the restaurant that did it. I was eating with my lover and my daughter on a June evening in Altona when I found myself being distracted by the rooms of light, quite empty, that floated behind my daughter's back. Every ten or fifteen minutes there would be another one heading off into the night, passengerless, to complete a huge orbit of Melbourne.

I went home and entered the bus route number in my computer. I discovered that seven orbital bus routes – the longest suburban ones in the country – were launched in Melbourne in 2009 to complement the existing radial spokes. The transport map of Melbourne, once a giant crooked asterisk, had become a web, at last allowing cross-town travel by public transport.

Strangers to Melbourne might do laps on the City Circle tram, or buy a ticket for the Melbourne Visitor Shuttle, or pop down to the Yarra to go on a river cruise. Instead, I opted to take a ride on one of these orbital routes.

First, some figures, to put things in perspective. The longest orbital route, the 901 from Frankston to the airport, clocks in at 114 kilometres. The journey from start to finish takes four hours. For some reason, the 903, from Altona to Mordialloc, which transcribes a massive, jagged arc around Melbourne's suburban sprawl, takes four and a quarter hours to complete eighty-six kilometres. This represents an average speed accomplishable, even by someone like me, on a bicycle.