Johannesburg - Vehicle sales are likely to increase by 15.2% to 567 850 units in 2011, Wesbank said on Monday."If one plots vehicle sales against interest rate movements over many years, we have a minimum of seven growth quarters ahead of us," said Wesbank chief executive Brian Riley.The group was particularly optimistic over the continued improvement in passenger vehicle sales for the year."The buy-down will continue with the higher LSM (living standards measure) segments leading the way. We suggest that passenger vehicle sales will be up 15% on the back of a strong rand, plenty of new models and a shortage of late model used cars."Sales in light commercial vehicles were also expected to strengthen. Medium, heavy and extra heavy vehicles would continue to recover at 20%, 15% and 30% respectively.Growth on the sale of busses was expected to fall by 30%, Riley said.The structural and rational part of the South African economy was geared for growth, a key reason why the company was confident at its outlook for the sector in 2011."Capital inflows remain healthy, while interest rates remain low with a 0.5% increase probable towards the back end of the year. Corporate profits are generally healthy with corporate listings and activity on an upward trend."The increase in sales predicted for 2011 was a "return to par" after the market over-corrected in 2009.