A highly urbanized version of MM5 (by use of the Martilli-Dupont-Taha scheme) has improved its performance in simulation of Houston and NYC urban transport and temperature characteristics. In particular, the EPA version of MM5 (called uMM5 at SJSU) better simulates canopy-layer and PBL met fields by use of a drag-force approach in lieu of typical roughness length theory. It also accepts available fine-resolution input parameters obtained from a high resolution urban LU/LC data set collected by airborne lidar. The model was used with data from both the Texas2000 field study and the NYC DHS MSG UDS tracer study. Results from the uMM5 and standard MM5 models showed both more accurate urban heat islands (UHIs) and urban transport winds from the uMM5 simulations. In particular, the Houston low-speed results shoed a strong daytime UHI, which was responsible for the observed convergence of ozone into the city, while the high-speed NYC results showed no UHI, but they did show a building induced barrier effect that produced divergent transport around the city. The uMM5 met fields from the the Houston results are being fed into the CAMx photochemical model, while those from the NYC results will be used to provide time and space varying boundary conditions to a variety of rapid and CFD ER urban canopy and canyon flow and dispersion models.