Rental cars are often viewed as being among the safest vehicles on the road, given their generally low mileage and the perception of many people that they are regularly - even scrupulously - maintained. That view is being questioned and currently under strong challenge by the National Highway Traffic Safety Administration (NHTSA), which says that it is investigating the repair histories of thousands of fleet rentals owing to "incidents involving allegations of personal injury and death." A number of car accidents have been alleged as a result of failure to hold and repair recalled vehicles, including a case in which an Enterprise outlet rented a recalled vehicle subject to a fire risk to two women who died when the car burst into flames and hit a truck. Enterprise admitted liability in that case and just settled a wrongful death suit with the women's survivors for $15 million The NHTSA is acting pursuant to a formal petition filed by the Center for Auto Safety, which alleges that rental car companies might not always be removing recalled vehicles from service and repairing them before letting customers once again drive them. Although the focus is on all the major car rental companies, it is most specifically directed at Enterprise Holdings Inc., the largest of all the operating groups. Enterprise has about one third of all the rental car business in the United States and has over one million vehicles in its fleet. A spokeswoman for the company states that it does routinely hold and fix vehicles when manufacturers recommend grounding them. The NHTSA is specifically focused on that response, with its audit of close to 30 fleet models examining their repair histories. Related Resource: "U.S. Probes Rental-Car Companies over Recall Repairs" November 22, 2010