Note the importance of pent-up demand for consumer durables. The candidate concludes:

We studied U.S. car retail time series to see the demand build-up phenomenon. After adjusting the relation with the GDP by the regression analysis, we found that the residuals fit best to the  ARIMA(1,1,1)(1,0,0)_{12} model. The statistically significant seasonal AR component and the MA component indicate that the demand builds up/down stochastically with time.