As mandated by the Minnesota state legislature, Mn/DOT conducted a test of the impacts of shutting down the Twin Cities ramp metering system in the fall of 2000. This test was conducted by an independent team of consultants directed by Cambridge Systematics, Inc. Traffic operations and accident data were examined for a pre-shutdown period between September 11 and October 15, and during the shutdown between October 16 and December 8. Market research to assess public opinion about the ramp metering system was also gathered during both periods.