Congress has played a central role in the MRAP program by suggesting to defense and service officials that MRAPs would provide far superior protection for troops than did the up-armored High Mobility, Multi-Wheeled Vehicles (HMMWVs ). Congressional support for MRAPs, as well as fully funding the program, has been credited with getting these vehicles to Iraq and Afghanistan in a relatively short timeframe, thereby helping to reduce casualties. Congress may likely continue to be interested in the MRAP program to ensure that the appropriate types and numbers of these vehicles are fielded, as well as to monitor the post-conflict disposition of these vehicles, as they represent a significant investment. In 2007, the Department of Defense (DOD) launched a major procurement initiative to replace most up-armored HMMWVs in Iraq with Mine-Resistant, Ambush-Protected (MRAP) vehicles. MRAPs have been described as providing significantly more protection against Improvised Explosive Devices (IEDs) than up-armored HMMWVs. Currently, DOD has approved an acquisition objective of 25,700 vehicles, of which 8,100 are the newer Military- All-Terrain Vehicle (M-ATV) version, designed to meet the challenges of Afghanistan's rugged terrain. DOD officials have indicated that this total may be increased depending on operational needs in Afghanistan. DOD reports that as of January 6, 2011, 13,624 MRAPs had been delivered to Afghanistan, including more than 6,500 M-ATVs. The Army has recently said that it will begin development of yet another MRAP version-the 'Ultra-Lite MRAP'-which raises questions about possible vehicle redundancies. The Marines, although voicing support for the M-ATV program, have retrofitted a number of MRAPs with new suspension systems and reportedly are satisfied with the results.