Richie's lawyer, Shawn Chapman, entered the plea on the star's behalf, who did not appear in court.
Because of a prior driving under the influence (DUI) conviction in 2003, by California law she faces mandatory jail time of 90 days and up to one year in prison if convicted of a second DUI.
The 25-year-old was spotted driving the wrong way down a Los Angeles freeway on Dec. 11.
Authorities found her stopped in a carpool lane and she subsequently failed a field sobriety test.
According to police, Richie admitted to officers at the time she had smoked marijuana and taken the painkiller Vicodin.
She was booked and released the next morning after posting $15,000 bail.
A pretrial hearing has been set for April 2.
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