Pour alimenter le debat sur les 4*4, une etude interessante venue de l'autre coté de l'Atlantique :
La raison souvent invoquée par les lobbys automobilistes americains (utilisateurs et producteurs) lors des discussions sur les textes de lois visant a reduire la consommation en essence des vehicules est qu'il ne faut pas empecher les gens d'acheter des 4*4 car ca leur permet d'etre plus en securité. Bien sur, on imagine bien que si les occupants sont plus en securité, ce n'est pas le cas des tierces parties impliquées dans les accidents. L'etude dont le résumé est ci-dessous quantifie cela : pour 1 million de conducteurs qui passent d'un vehicule leger à un 4*4, de 34 à 93 personnes supplémentaires meurent dans un accident impliquant un 4*4. De plus, il apparait que si pour une personne qui evite effectivement d'etre victime d'un accident fatal en changeant de vehicule, 4 personnes exterieures au 4*4 (pietons, cyclistes, etc.) supplementaires sont tuées dans des accidents impliquant un 4*4 !


Drivers have been running an "arms race" on American roads by buying increasingly large vehicles such as SUVs and light trucks. An important reason for the popularity of large vehicles is that families view them as providing better protection to their occupants if a crash occurs. But when families drive large vehicles, they pose an increased danger to occupants of smaller vehicles and to pedestrians, bicyclists and motorcyclists. This study measures both the beneficial internal effect of large vehicles on thier own occupants' safety and their negative external effect on others. The results show that light trucks are extremely deadly. For each one million drivers that shift from driving cars to driving light trucks, between 34 and 93 additional car occupants, pedestrians, bicyclists or motorcyclists are killed per year and the value of lives lost is between $234 and $624 million per year. The safety gain that families obtain for themselves from driving large vehicles comes at a very high cost: for each fatal crash that occupants of large vehicles avoid, more than 4 additional fatal crashes involving others occur.

Michelle J. White is Professor of Economics at the University of California, San Diego, and a Research Associate at NBER. She received her Ph.D. in economics from Princeton University in 1973 and was formerly a faculty member at the University of Pennsylvania (1973-78), New York University (1978-83) and the University of Michigan (1984-2000). She has been at UCSD since 2001. She has also been a visiting professor at Yale, Wisconsin, Chicago, and Tilburg (the Netherlands) and a visiting scholar at Harvard Law School, Berkeley, the Hebrew University, Copenhagen Business School, and the Universities of Bonn, Tel Aviv, Uppsala, and Munich. Her current research involves examining the causes and consequences of asbestos exposure and asbestos litigation in the U.S. She also does research on topics in public economics, including the effect of Proposition 13 in California on household mobility and the effects of SUVs and pickup trucks on traffic safety.