Iowa Highway 32, also known as the Northwest Arterial, is a state highway that runs north–south across part of Dubuque County, Iowa. Highway 32 is among the shortest state highways in Iowa, at approximately 5 miles (8.0 km) long. The northern terminus of Iowa 32 is in Sageville, Iowa, where it meets U.S. Highway 52/Iowa Highway 3 (Central Avenue) at John Deere Road. The southern terminus of Iowa Highway 32 is in the west side of the City of Dubuque, where it meets U.S. Highway 20 (Dodge Street). With the exception of a small stretch in the north, the entire highway is within the City of Dubuque.

Iowa Highway 32 begins at an intersection with U.S. Route 20 (US 20) in Dubuque. From US 20, Iowa 32 heads north and immediately drops 100 feet (30 m) in elevation into the valley of the middle fork of Catfish Creek. It heads back uphill and intersects Pennsylvania Avenue. A mile (1.6 km) north of this intersection is another intersection with Asbury Road, named for the small town 3⁄4 miles (1.2 km) west of the intersection.

North of Asbury Road, the Northwest Arterial is flanked on both sides of the road by retail establishments, most of which popped up in the early-2000s. The highway makes a 45° turn to the northeast, heading towards Sageville. Just to the northeast is an intersection with John F. Kennedy Road (JFK), which for the first six years of Iowa 32's existence, was the northern end of the route. Northeast of JFK, the highway passes the Dubuque Arboretum and Botanical Gardens. Just to the northeast of the arboretum is the intersection with U.S. Route 52 / Iowa Highway 3 in Sageville.

Iowa 32 was originally envisioned in the 1970s as part of Dubuque's long-range transportation improvement plan. The road was planned as a four-lane highway bypass and alternate route to U.S. 52, which runs as a city street through Downtown Dubuque. Construction began in the early 1980s on a two-lane section, which stretched from U.S. 20 (Dodge Street) to John F. Kennedy Road.

The city turned the highway over to state control in 1995, where it was marked as Iowa Highway 32. By 1997, work was finished on the additional two lanes, and the road was a four-lane divided highway. In 2002, the state completed a four-lane extension of the highway north to US 52 / Iowa 3, creating a bypass from US 20 to US 52 / IA 3.

Since the completion of the highway, there has been significant growth along the Northwest Arterial corridor. The largest developments include Asbury Plaza, Iowa's 8th-largest shopping center, and Medical Associates Clinic's West Campus. In addition to these, several business parks and residential subdivisions have been built in the corridor. This growth, and its subsequent increase in traffic, has placed strains on the road, and has led to the installation of numerous stoplights. The growth has also led to more traffic accidents, particularly at the Asbury Road and U.S. 20 (Dodge Street) intersections.

The Northwest Arterial is the third highway to be designated as Iowa Highway 32. The first Highway 32 was in Cherokee County, Iowa, extending from Iowa Highway 5 to Cleghorn, Iowa, and was in existence from 1920 to 1926. A route from Iowa Highway 9 near Spirit Lake, Iowa to U.S. Highway 71 in Milford, Iowa served as the second Iowa Highway 32 from 1934 to 1980.

For many years, leaders in the Dubuque government and business community have been lobbying state and federal lawmakers to finance an extension of Iowa 32. The extension, to be called the Southwest Arterial, will run 6.1 miles (9.8 km) from U.S. Highway 20 (Dodge Street) in the north to U.S. Route 61 and U.S. Route 151 in the south. The project's main purpose is to relieve traffic congestion on local surface streets and remove thru traffic from city neighborhoods. The completion of the highway is part of the city's long-range transportation improvement plan.

However, construction of the highway has not yet started, and its progression has been plagued with numerous delays. It has been slowed by environmental impact studies, roadway alignment studies, and above all, its massive cost. The extension, originally projected in the range of $50–70 million, has now climbed above $100 million. In 2005, then-Iowa congressman Jim Nussle secured $20 million in federal financing for the project. Preliminary design was completed in March 2008, with final design and property acquisition to commence at that time. Plans call for two lanes with partial interchanges to be built starting in 2010.

Also, there is some controversy over the alignment of the Southwest Arterial. The city has proposed the northern end of the highway meet U.S. 20 at Seippel Road, near the Dubuque Industrial Center West. This is most likely due to the cheaper cost of building the road over flatter, less-developed land, enabling construction to begin sooner. However, this option would not link the highway directly with the northern section of Iowa 32 (Northwest Arterial), thus not providing the "direct" beltline, which was the project's original goal.

The entire route is in Dubuque County.