Which of these is a common method to enhance physical security in sensitive areas?

Enhancing physical security in sensitive areas often involves implementing measures that can deter unauthorized access and protect both personnel and assets. Among the options given, the use of bollards is particularly effective because these sturdy posts can prevent vehicles from entering restricted areas, thereby protecting the perimeter from potential breaches or attacks. They serve as a physical barrier that can stop or slow down intruders, especially in situations where a vehicle could be used as a weapon.

While other methods like lighting, fire alarms, and surveillance cameras play important roles in overall security, they focus on different aspects. For instance, lighting improves visibility and can deter criminal activity by making areas less attractive for illicit behavior. Fire alarms are critical for safety regarding fire hazards but do not primarily contribute to security against unauthorized access. Surveillance cameras are vital for monitoring and recording activities, which can aid in identifying threats after they occur or in real-time, but they do not physically prevent unauthorized entry.

Thus, bollards stand out as a proactive physical measure that directly enhances security by physically restricting access to sensitive areas.