The 33-year-old DJ - who was previously in a relationship with troubled actress Lindsay Lohan - was arrested for speeding in her black Porsche while on the way home to Los Angeles from a gig in Las Vegas at 10.30am on Monday (01.08.11).
She refused to take a breathalyser test and was arrested and transferred to the Baker Sheriff's Department police station where she registered as being over the legal limit for alcohol in her system.
Samantha was consequently charged with DUI and released without bail at 5.30pm.
It is the second incident Samantha has suffered in recent months while on the roads - in April she was left with a bruised and cut face after she was cycling home from a gig in Los Angeles.
She also suffered a graze across her forehead and a split lip, and urged people to wear a Helmet because of the incident.
Samantha - the sister of music producer Mark Ronson - said: "Let this be a lesson ... if you have a driver's license you probably don't need to be on a bmx bike ... Wear a helmet kids!!! (sic)"