181,434 units registered equate to a 7.2 per cent drop compared to April 2016, with ACEA blaming the Easter holiday break for the decline.
“Demand declined in all segments … and across all major EU markets,” the Association said.
The United Kingdom (-14.9 per cent) and Germany (-11.8 per cent) saw the highest drops, according to ACEA, while the Spanish (-1.0 per cent) and French (-0.4 per cent) markets remained “more or less stable”.
During the first four months of the year, the overall EU market still expanded by 3.8 per cent, counting 788,181 new commercial vehicles registered.
Over the same period, Spain (+14.5 per cent) and Italy (+8.2 per cent) posted the strongest increases, followed by France (+6.7 per cent) and Germany (+2.0 per cent).
The UK market declined slightly (-3.1 per cent) during these four months, ACEA said.