WASHINGTON - The number of accidents caused by young drivers is linked to the age and number of passengers in the vehicle, according to a study.The American AAA Foundation for Traffic Safety says collision data collated from 2007-10 indicated a strong link between the number and age of passengers in cars and the risk of a teenage driver dying in a crash, with the likelihood increasing with each additional passenger.44% INCREASEPeter Kissinger, president and chief executive of the foundation, said: "It's a dangerous mix when peers are passengers in a car with 16 or 17-year-old drivers."According to the study, the risk of death for a 16 or 17-year-old driver increased by 44% when carrying one passenger younger than 21 instead of driving alone. The risk doubled with two passengers younger than 21 and quadrupled when carrying three or more passengers younger than 21.Car accidents remain the leading cause of death for teenagers in most First World countries. Safety experts have recommended licensing laws that allow no more than one passenger during the first six months that a teenager has a licence, or stipulating that an adult must accompany the driver.WHEELS24 says: Perhaps the US authorities should raise the learner-driver age limit to 18. Amazingly, the last US state to insist on a driving test was South Dakota - and that was only in 1959!