New vehicle sales slumped as 2018 progressed. What was the cause and will the downturn continue? Our investigation reveals that there were several influential factors, although two acting together were the major cause. The research indicates that there was a perfect storm in 2018 rather than the start of a long-term decline. While the future depends on the trajectory of several factors, it is likely that sales will continue to be soft in 2019 and possibly 2020. There are good prospects for a recovery in sales in the longer term.