SACRAMENTO (CBS13) — An avoidable tragedy in 2015 is behind the new legislation going into effect next week.

After being left on a bus for nine hours in 90-degree heat on Sept. 11, 2015, 19-year-old Paul Lee, who had autism, died in Los Angeles County. He was reportedly found in his own vomit on the locked bus.

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“We failed to protect Paul. Paul, I love you. I miss you. I’m so proud of you. See you in heaven,” Paul’s mom said in a 2016 press conference.

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The California law named in Paul Lee’s honor is designed to prevent future tragedies and goes into effect next Friday.

Some districts have already implemented the changes, which require buttons installed at the back of every bus to remind drivers to check the seats before they leave.

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Find out how these changes will protect all school children tonight on the CBS13 News at 10.