United States federal safety investigators have recommended that 15-passenger vans be equipped with additional safety belts and stronger roofs to prevent injuries during accidents, especially rollovers, the Detroit News reported.The paper said investigators also called for better training and licensing for drivers, who are often ill-equipped to handle the vehicles when fully loaded with passengers and cargo.The National Transportation Safety Board made the findings following a two-year investigation into van crashes in Texas and North Carolina, the Detroit News said."We have identified a gap in (federal safety) rules," NTSB chairwoman Ellen Engleman said, according to the newspaper. "We have a vehicle designated as a bus, but structurally, it's not built to the same safety standards as a bus."Engleman also said the vans have been engineered and marketed outside the parameters of the safety standards that apply to a commercial vehicle, the Detroit News said."(These vans) are sold essentially as a passenger vehicle on a dealer's lot, but its design characteristics as well as the driving characteristics are quite different from that of a passenger vehicle," she reportedly added.The newspaper said the board is recommending that the National Highway Traffic Safety Administration require the same standards for interior padding and roof strength to 15-passenger vans as well as cars. The NTSB only has the power to recommend changes to vehicle safety regulations. They must be implemented and enforced by the NHTSA.The board also called on Ford and General Motors, the only manufacturers currently selling large vans, to voluntarily adopt new designs while NHTSA completes new regulations, the Detroit News said.