You're not wrong; the commute on Melbourne's major roads has got a lot worse in the last five years.

In fact, Melbourne's motorists have slowed down more than any other capital city in Australia.

Take the trip to Tullamarine on Australia's most congested air route: travel speeds between the CBD and Tullamarine Airport have dropped by nearly 20 per cent between 2013 and 2018, according to the latest study by the country's peak motoring body, the Australian Automobile Association.

Anyone trying to get back to town after a flight, driving from the airport to the CBD during the morning peak period, is travelling at speeds as slow as 51km/h, adding an extra 3.3 minutes to the journey.

The sluggish flow of traffic on the city's increasingly choked roads has revived calls for a congestion levy, notably from Melbourne City Council, Infrastructure Victoria and even the the RACV, but the Andrews government is steadfast in its refusal to tax motorists.