Trucks are fair game when it comes to graffiti. Most graffiti stays in the one place, with the exception of trains, trucks or any other mobile vehicle. Trucks are unique in their own way because unlike trains they are flexible and don't have a set route or line. This can give the artist free advertisement moving across the city. Trains are buffed daily, but white canvas trucks often have years of paint accumulation. Truck bombing is generally quick and its dominated by tags and throw-ups. Pieces are rare because they take longer. Speed and efficiently is essential for the best artists to maintain their street profile. Truck bombings occur when there is surrounding high-density graffiti like the inner-suburbs of Melbourne.