The amazing car-crash in the opening sequence was done by digitally compositing shots of Julia Roberts taking off with the car and a radio-controlled car being hit by a stunt driver.
The burgundy t-shirt with gold lettering she wears that is cut off says "Oakton Cougars". The costumers found this t-shirt in a thrift store and bought it, then researched online where this school may be. Once they learned that it is a high school in Vienna, Virginia, they contacted the school to ask if they could use the t-shirt in the film.
Julia Roberts won the Academy Award for best actress for her role as Erin Brockovich and famously forgot to thank Brockovich in her acceptance speech. Afterward she was quoted as saying, "It doesn't bring out the Einstein moment that you hoped it would."
There are actually 5 people who went onto play in big TV shows. T.J. Hyne who played the law clerk PG and E sent in at the first plays Dr. Jack Hodgins on Bones.
The character George, the biker boyfriend played by Aaron Eckhart, was based on Erin's Mexican-American biker boyfriend Jorge. Erin and Jorge did break up, but he did not leave her life. He was hired as a full time live-in nanny for Erin's children for several years, paid for by the law firm so that she would have more time to devote to her work.
Julia Roberts is one of two Best Actress winners to portray a right handed character although the actress is naturally left handed. Two years later, Nicole Kidman won her Oscar for playing right-handed Virgina Woolf in The Hours (Kidman is also left handed).