India, April 14 -- Britney Spears voluntarily checked into rehab on Sunday following her March arrest on suspicion of driving under the influence, a representative told Reuters on Monday. The California Highway Patrol said the pop singer was arrested in Ventura County after officers stopped her BMW following a report it had been travelling erratically at high speed. The highway patrol said that Spears "showed signs of impairment" due to what officers suspected was the influence of a combination of alcohol and drugs. It added she underwent a series of field sobriety tests. Spears was booked into the Ventura County Main Jail and is due for a court appearance on May 4. Spears has struggled for years with intense media speculation into her pers...