Speed bumps installed on Dolores Street in San Francisco after skateboarding injuries

SAN FRANCISCO (KGO) -- The city of San Francisco has installed small speed bumps near Dolores Park -- apparently to slow down skateboarders.

Jeffery Tumlin, the head of the San Francisco Municipal Transportation Agency, tweeted that he "hates doing this" but that two people have recently suffered life threatening injuries during "hill bombs." Tumlin first tweeted there were fatalities, but later corrected that they were critical injuries.

The speed bumps could be seen on Dolores and 20th streets.

Hill bombs are unsanctioned events that draw large crowds to see skateboarders go as fast as they can down hills.

Tumlin said he's consulting with leaders about building stronger skate culture and co-designing "slow streets" in the city.

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SF Supervisor Rafael Mandelman also shared on his Facebook that there's been three accidents in a little over a week.

"Last weekend multiple people were transported to SF General with serious injuries, including someone who is still there in a coma. Today a pedestrian was hit and is being administered CPR and another person is experiencing seizures. Neighbors have been assaulted and nearby schools and homes have been damaged. This has to stop," his Facebook post wrote.

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