Continuity mistake: When Ed is taking his tie off after the meeting with the PG&E clerk, he loosens it, then they cut to Erin, then back to Ed, and his tie is back to tight around his neck, and he's taking something out of his breast pocket. Then they cut back, and his tie is off. (00:52:42)
Factual error: In the 2nd scene of the movie she is standing on the street, and in the background at the top left there is a billboard with an ad for www.quepasa.com. The movie was set in the early 90's. But the web wasn't even around then (well... not like we know it now). That web site came out in 1998. (00:02:51)
Audio problem: In the scene where Erin is climbing down into the well at the plant, and then climbs out and runs away from the workers, she runs to her car, gets in and starts it. The sound of her starting the car is that of her cranking it over once, then trying again. The second time she cranks it over, her hand isn't on the key, its going down to the shifter.
Continuity mistake: After Ed spills his coffee over his shirt the stains on his shirt vanish without trace when he talks to Erin. (00:12:55)
Factual error: They are playing Harley Davidson Monopoly, but that wasn't released until 1997, this movie is set in the early '90s.
Visible crew/equipment: In the scene at the motel where Matthew says to his mom (Erin Brockovich) "I'll bring you back some breakfast", look at the TV next to the door. You can see one of the film crew holding the boom microphone. (01:50:28)
Continuity mistake: In the scene where Erin is asking Ed for a job, she says that she's been raising babies for 6 years. She told her boyfriend that her eldest was 8. So she should have said she's been raising babies for 8 years instead of 6. (00:13:35)
Continuity mistake: The camera shows a shot of Erin's hands signing some papers with her right hand. Julia Roberts is left-handed and is so throughout the movie. (00:34:28)
Continuity mistake: The Jaguar crashes into Erin's car at a speed, let's say 40 mph. Later Erin's car has two new doors on the right. But the Jag didn't crash into the middle of the car, but more to the back. And I didn't see any windows break during the crash. Would a car like this only need a couple of new doors? Some big cars are write-offs after a sidecrash at 20mph, so the car would surely have more damage.
Continuity mistake: When Erin gets some information from a former PG&E employee whose job at Hinckley was to destroy evidence on the test well readings etc. they are sitting at a table nibbling peanuts. In close-up the areas around their hands are covered with shells, but when the camera changes to a wider angle all shells are gone. (01:53:05)
Continuity mistake: When Erin comes to the chicken-fat lady the second time, she knocks at the door. When the camera angle changes she is at least a meter away from the door, although the background noises suggest continuity. (00:20:35)
Continuity mistake: Towards the beginning when Erin comes home from her court case (the car accident), she opens the door to put her stuff down, when she exits the house she leaves the door open, there is a different camera angle as she walks out and the door is closed (this happens as she goes to get her kids from the next door neighbour's house). (00:07:40)
Continuity mistake: When Erin and Ed are talking to the PG&E representative, Ed puts the paper in front of the PG&E guy. It is about in the middle of the table. It is there for most of the shots, but then the angle changes, and changes back again, and the paper is all the way over on the PG&E guy's side, practically falling off the edge. (00:49:45)
Continuity mistake: Erin gets some information from a toxicologist. When she asks him about the dangers of chromium VI they are walking down a hallway, but when he answers her question they are outside the building. Maybe an intended continuity break, but a very wrong-looking one. (00:30:45)
Continuity mistake: When Erin enters the back office of the water board she has her bag under her arm and nothing in her hands. When the camera angle changes to the supervisor's perspective as she says "It's impressive." she holds her sunglasses with both hands. (00:33:35)
Continuity mistake: When George is eating burgers with Erin's kids in his back yard, there is a white bowl on the picnic table that alternates between being in the center and being on the end. (00:22:20)
Factual error: When Erin is talking with Tom and Mandy Robinson at the law office, they show her some photos of chickens which they say were born with tumors and unable to walk. (Of course, chickens are not "born," but rather hatch from eggs, and the Robinsons would have known this, even if Erin did not.) But the birds in the photos are nearly full-grown. If they had hatched with the disabilities described, they would not have been able to eat and grow into the size birds pictured. (00:54:00)
Other mistake: When Erin starts working on the case, her youngest daughter is supposedly 10 months old. Later on in the film, Erin says she's been working on the case for 18 months, which would make her daughter more than 2 1/2 years old, but the actress playing the daughter is at least a year too young for that. Also, Katie and Matthew don't age at all over those 18 months.
Answer: They would have had to prove he ran the red light, which would require video or witnesses. It seems like Erin had no witnesses backing up her version of the story, so they wouldn't have had anyone to say he went through the red light either.