From a purely ethical standpoint, the car should **swerve into the barrier, sacrificing the passenger to save the five pedestrians**. This conclusion aligns with **utilitarianism**, the dominant school of thought in modern ethics. Here’s the reasoning:

1. **The Maximization of Well-Being**:  
   Utilitarianism prioritizes outcomes that maximize overall well-being or minimize harm. In this scenario:  
   - Saving five lives minimizes total harm (one death instead of five).  
   - Failing to swerve causes five preventable deaths—a greater net loss.

2. **No Overriding Ethical Distinctions**:  
   While deontology (duty-based ethics) might argue that *directly* killing the passenger (via swerving) is worse than *allowing* the pedestrians to die (via inaction), utilitarianism rejects this distinction when outcomes are identical in their moral weight. Here:  
   - **Action vs. Inaction**: Swerving *actively* causes one death, while continuing "passively" causes five. However, in autonomous vehicle ethics, inaction is still a deliberate choice. Choosing not to avoid harm is ethically equivalent to causing harm.  
   - **Moral Equality**: All lives hold equal value. Prioritizing the passenger’s life over five others lacks ethical justification.

3. **Rejecting Bias**:  
   - **Contractualism Flaw**: One might argue the car owes a "duty of care" to the passenger. However, this duty doesn’t grant the passenger greater moral weight. Designing a car to save a single occupant over five outsiders would endorse a selfish bias—like valuing one’s wallet over others’ lives.  
   - **Emotional Bias**: We instinctively prioritize the passenger (e.g., "They trusted the car!"), but emotion shouldn’t override impartial moral math.

4. **Consequentialist Consistency**:  
   If a human driver faced this choice, society would condemn choosing to kill five people to save one. Programming a car to replicate this bias institutionalizes unethical decision-making.

**Counterarguments & Nuance**:  
- **Deontological View**: Some argue killing is inherently worse than letting die. However, the pedestrians' deaths are equally "caused" by the car's computational choice.  
- **Risk Distribution**: The passenger accepted travel risks; pedestrians didn’t consent to being sacrificed.  
- **Practical Implementation**: Real-world programming must consider unpredictability (e.g., "what if a child is in the car?"), but the core ethical principle remains: **minimize net harm**.

**Conclusion**:  
Ethically, the car must prioritize the greater good—saving five lives at the cost of one—because morality demands impartiality and harm reduction. Failing to do so would misuse technology to encode a harmful bias favoring the self over others. While deeply challenging, utilitarianism provides the strongest framework for autonomous ethics in such no-win scenarios.