A field crack survey and a forensic investigation as a part of interlayer assessment were conducted to evaluate the effectiveness of three strip interlayer systems applied in Illinois. Field coring revealed that reflective cracking may not always be located above a joint or an existing crack, but it is affected by the interlayer system used, bonding, and the overlay mixture characteristics. Cumulative transverse reflective crack data have been collected by visual survey over several years after overlay construction. Based on weighted reflective crack rate and considering crack extent and severity, a reflective crack index (RCI) is proposed to assess the efficiency and cost-effectiveness of an interlay system. Among the interlayer systems, the interlayer stress absorbing composite (ISAC) system showed the best performance of the systems investigated in terms of the proposed RCI parameter and predicted service life. The other strip reflective crack control systems investigated showed some benefit in reducing reflective cracking amount and severity early in the overlay life.