The Defense Department and the communities that benefit from its military bases should shell out more money for transportation improvements to handle the “significant” traffic expected to result from a major relocation of military workers in the Washington region, according to a new report. Congress should provide an emergency funding infusion similar to the stimulus program to begin immediate relief such as creating high-occupancy toll lanes and carpooling programs to offset the effects of 180,000 military and civilian workers moving at 18 bases around the nation, according to the report from the National Research Council’s Transportation Research Board. “We advocate doing these things as quickly as possible,” said Joseph Sussman, a Massachusetts Institute of Technology professor who led the study.