SAN FRANCISCO (CBS SF) — CHP in San Francisco issued a severe traffic alert Friday afternoon following an injury accident that for a time blocked all southbound lanes of U.S. Highway 101.

The Twitter account posted about the incident north of the Cesar Chavez Street exit at 12:40 p.m. In addition to blocking all southbound lanes, the crash is also blocking the left lane in the northbound direction of Highway 101.

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There were reports on social media that the accident involved a motorcycle.

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Shortly after 1 p.m., CHP updated the incident, stating that the right southbound lane of the freeway had reopened, but the center and left southbound lanes and the left northbound lane were still blocked.

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At around 2:19 p.m., CHP said the left lanes in both directions of Highway 101 remained closed, but other lanes had reopened. The roadway did not fully reopen until about two hours later.