Blue Heelers (1993)

Season 4: Episode 17

Dash's career is on the line when is seems she waved her new boyfriend on instead of breath-alysing him. Dash explains that it was because she saw a couple, in the car behind, changing seats. But when she pulled them over, the driver was under the limit while the passenger was clearly drunk. The only way Dash can clear her name is to find some evidence that the couple did in fact swap seats. Unfortunately, it takes a fatal accident to finally prove she was telling the truth.