Protesters block traffic on I-43 Protesters blocked traffic on I-43 for a short time Monday. MILWAUKEE - Protesters blocked traffic on I-43 for a short time Monday, April 12. The march began at Rose Park in the Harambee neighborhood. Demanding change, the group said they are fed up with law enforcement killing people of color. The Milwaukee demonstrators joined others across the country. Advertisement The march stretched across the north side, eventually heading into traffic on I-43 northbound. Law enforcement temporarily shut down part of I-43. State Representative David Bowen was with the group at the beginning of the march. He said people need to continue to use their voices and votes to demand change.