Sims was in his car, which has legislative plates, when a man in another car started honking, then pulled up next to him with a gun.
"I don't even know when he got behind my car, and then when he pulled in front of me, and slammed on his brakes, I didn't know what was going on," Sims said. "I'm looking around, you know, thinking about January 6th."
Sims was referring to the storming of the U.S. Capitol Jan. 6 and heightened security at state capitols across the country after the incident.
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The suspect was later arrested, but he was released the very next day after posting bail.
Sims was the Senate sponsor of legislation to eliminate the state's cash-bail system.
"I think this is a perfect example of how the cash-bail system does not make us more safe; he is free tonight on cash bail," Sims said. "If the Safety Act were in place, that would be very different."
Formal charges against the suspect are pending.