Out-of-cell interference is an important factor in determining the system capacity of CDMA systems. Out-of-cell interference is in ̄ uenced by propagation parameters such as slope index s of the path loss model, the standard deviation r of shadow loss, and the correlation coef® cients of shadow loss for propagation from the desired base station and from the interfering base station. For line-of-sight (LOS) cells along streets or roadways, propagation may be described by a two-slope model that has smaller slow-fading loss r and a larger slope index past the breakpoint Rb than the single-slope model. As a result, smaller out-of-cell interference is obtained with the two-slope model, leading to system designs having less infrastructure than are obtained using the single-slope model. In this paper we examine how a more realistic prediction of quality of service (QOS) made with the two-slope model leads to cost-effective system designs.