The paper reports the distributions of noise level maxima, LAFmax, generated during the pass-by of over 85 000 vehicles in service on urban arterials and motorways. These were measured under normal traffic and vehicle operating conditions on multilane roadways. They are indicative of the instantaneous maximum noise levels that would be experienced in the free field at the set-back distance of the facades of the first row of many dwellings fronting urban roadways in Australia, from vehicles travelling in the nearside lane. Noise levels are reported separately for four classes of vehicle and for roadways with five different posted speed limits. Results have been standardised as free-field levels 15 m from the centreline of vehicle travel. The data were collected in Brisbane but can be assumed to be representative of noise level maxima from vehicles operating throughout Australia. Maximum noise levels increase with vehicle class (from cars through to articulated trucks) and with roadway speed limits. The within-vehicle-class variance is large and the distributions of maxima from different vehicle classes overlap extensively. Sound Power Levels of the observed vehicles agree well with those from the European IMAGINE emission model. This investigation contributes essential information regarding the source and levels of noise events adjacent to urban road networks - the likely determinant of human sleep disturbance.