Protesters blocked all eastbound lanes on the Beltline at West Broadway for several hours Thursday night, the Wisconsin Department of Transportation reported.
The blockage of all lanes of the eastbound Beltline started at 7:33 p.m. and ended at 11:16 p.m., according to DOT.
No crashes or other incidents were reported by police.
The protesters had set up grills on the highway just east of South Towne Drive, Monona Police Chief Walter Ostrenga said Thursday night, and he asked motorists to avoid the area.
Madison police said the protest began at around 7:30 p.m. when a group of about 30 cars was moving at about 10 miles per hour on the Beltline.
The protest stemmed from police-involved deaths, including that of Breonna Taylor in Louisville, and the Black Lives Matter movement, but it was unclear Thursday whether the protest was the result of a specific incident.