In order to make civilian supersonic flight over land possible, the resulting sonic boom must be acceptable to the people exposed. In order to determine the impact on people, determining the behavior of a sonic boom in a large city is critical. A combined ray tracing radiosity method was developed to propagate sonic booms into urban canyons. A variety of environmental parameters were changed to determine their effect on the resulting sound field. The arrival angles of the boom, the height of the canyons, the width of the canyons, and the amount of diffusion were all varied. It was shown that the resulting sound levels from most of these parameters was highly dependent on the combination of the parameters rather than a single parameter. Diffusion was the only parameter that showed a consistent trend in the amplitude of the sound field. [Work funded by NASA and the FAA's PARTNER Center of Excellence.].