This independent report on the results of a congressionally mandated study of reactive armor (RA) tiles for U.S. Army and Marine Corps armored vehicles was submitted to Congress in April 1999. It relies on an extensive supporting analysis conducted by the U.S. Army Materiel and Systems Analysis Activity in cooperation with the U.S. Army Research Laboratory. The study focused on two Army vehicles, the Bradley Fighting Vehicle (BFV) and the M113 family of vehicles. Three types of RA tiles were evaluated: the current "production" BFV tile, a new "1-2 year" developmental M113 tile, and a more advanced "2-3 year" design. All of these designs significantly improved vehicle survivability, but the 2-3 year tiles provided the most robust protection for both vehicles against likely 2005 threats. In the case of the M113, however, the somewhat lighter and less costly 1-2 year tiles might be preferred in situations where advanced threats are not so prevalent. The report makes several policy recommendations: (1) The Army should develop a new universal enhanced RA tile based on the 2-3 year design for both the BFV and the M113, at an estimated cost of $11 million. This effort should include the development of an optimum coverage pattern for the weight-constrained M113A3 tile sets. (2) Enough additional production tile sets should be procured to equip a substantial portion of the BFVs in the Army's Contingency Response Forces, and a sufficient number of the new enhanced tile sets should be procured to outfit an additional brigade of BFVs. At least this many M113A3 enhanced tile sets should also be procured, plus enough additional sets to meet identified needs. (3) Further research should be done on the need for RA tiles on M113s in their typical roles and missions, and on the appropriateness of RA for urban operations. Also, the Marine Corps and the Army should consider whether the new universal RA tile would be appropriate for other vehicles in the future, especially those being considered for the Army After Next.