EPA has been testing vehicles for many years using the Federal Test Procedure (FTP). However, localized control strategies or specific problems often require data that is not normally generated using the standard FTP. To meet these needs, specific test programs are undertaken to answer the questions raised. One recent program extensively investigated the effects of vehicle soak temperatures on emissions. To complement this effort, a short test series was undertaken to quantify the probable emission effects of a modified driving cycle and the results are the subject of this report. Specifically, this test program was designed to determine the effects of delaying vehicle warm-up. This was accomplished by substituting slow speed start-stop driving for the higher speeds normally used at the start of the standard driving cycle.