Eighteen million licensed vehicles are likely to be on Saudi roads by the end of this year, from 17 million last year, according to a study published by Al-Eqtisadiah daily.The number of licensed cars rose by 7 percent from 2011 to 2012, to 15.9 million vehicles, it said. This was a rise of 975,000 cars from the 14.9 million in 2011.