Record-breaking crowds that overwhelmed San Francisco's transit system and streets following the July Fourth fireworks show have prompted an investigation by the San Francisco Municipal Transit Agency. The SFMTA, which had urged the public to rely on mass transit for the holiday, admitted it was unprepared for the surge of passengers. Tens of thousands of people — including NBC Bay Area reporter Thom Jensen — were caught in the gridlock after flocking to buses, trains and Waymo autonomous vehicles. Watch NBC Bay Area News free wherever you are Judson True, SFMTA chief of staff and external affairs director, updated the board on Tuesday regarding the transit and traffic failures that stranded attendees into the early hours of July 5. “We are still very much working through our lessons learned for July Fourth. But the broad outlines are clear,” True said. Traffic and transit systems were simply overwhelmed by the volume of people, True noted. “We have some initial data,” True said. “We know the Muni system, as a whole, carried 41,000 more people than on the previous July Fourth. That’s about a 13% increase.” While the SFMTA does not regulate general traffic or autonomous vehicles in the city, True explained that the Muni system experienced severe delays caused by the heavy volume of cars on the streets, drivers illegally using bus lanes and breakdowns involving Waymo vehicles. Local “Based on our observations that night, we believe it took our shuttles about 90 minutes to make a trip we expected would take 30,” True said. The following day, Muni riders told NBC Bay Area that commutes took up to three times longer than usual, with some passengers forced to wait hours for buses and trains. “There’s only so much you can do before you kind of just accept your fate,” BART