What is the common impact on highway capacity when incidents occur?

When incidents occur on highways, such as accidents or breakdowns, the common impact on highway capacity is that it is reduced for each lane that is blocked. An incident can obstruct traffic flow, resulting in a loss of available lanes for vehicles to use. When one or more lanes are blocked, this constricts the overall capacity of the highway, leading to increased congestion and delays.

Every lane that is obstructed typically translates to fewer vehicles that can travel through that section of the highway. The remaining open lanes often experience increased demand, which can lead to further reductions in flow as vehicles need to adjust to the available space. Thus, the presence of incidents generally leads to a decreasing capacity because the effective lane usage is compromised.

Understanding this concept is crucial for traffic engineers when designing systems to manage incidents and improve traffic flow, as it emphasizes the importance of rapid response to incidents to restore capacity as quickly as possible.