According to Pomona PD Sgt. Patrick O’Malley, the 24-year-old singer … also known as “Bikini Girl” … was arrested in Los Angeles at 12:16 AM … with her mother in the passenger seat.

Darrell allegedly told police she was en route to a nearby hospital … because her mom had fallen down at home.

But while Katrina was driving to the hospital, she allegedly ran a red light and smashed into another vehicle.

Darrell allegedly tried to flee the scene … but a nearby officer who heard the crash responded and pulled over Katrina’s 2004 Toyota Camry.

When the officer approached Katrina, he smelled booze … and gave her a field sobriety test. She performed poorly … and was arrested for DUI.

Katrina — who was crying hysterically during the arrest — was hauled to a nearby police station … where she took a breathalyzer test … and blew a .15 and a .17 … WAYYYY over the legal limit, .08.

Katrina was eventually cited and released just after 6AM. As for her mom, an ambulance was called to the scene of the arrest … but her condition is unclear.

Things could get worse for Katrina … we’re told she could also face charges for hit and run for allegedly trying to flee the scene of the initial accident.

We reached out to Katrina for comment — so far, no response.