TABLE 3 Summary of Model Runs,,, ,,, By tract,All variables ,No model input of any sort,Model 1 By tract,All variables,Model constrained,Model 2 By tract,Transportation land-use variables only,No model input of any sort,Model 3 By zip,All variables ,No model input of any sort,Model 4 By zip,All variables,Model constrained,Model 5 By zip,Transportation land-use variables only,No model input of any sort,Model 6