I-894 begins at the Zoo Interchange in Milwaukee with I-41, I-94, US 41, and US 45. The highway heads south as part of the Zoo Freeway from this interchange concurrent with US 45. Traffic reports generally refer to this section either as 894 northbound (southbound) or the northbound (southbound) Bypass. North of the Zoo Interchange, US 45 continues separately as the north part of the Zoo Freeway. I-894 enters West Allis before its first exit after the interchange; this first exit is a junction with Wisconsin Highway 59 (WIS  59), known locally as Greenfield Avenue. After the first three exits, I-894 enters Greenfield. Further south, I-894 has interchanges with National Avenue, Oklahoma Avenue and Beloit Road. This section of the bypass is usually congested during rush hour because of traffic on I-894 and merging traffic from the Rock Freeway (I-43). This 4 mile stretch usually has travel times between 10–15 minutes during the rush hour (as opposed to 5 minutes during non-rush hour times).