Why does load vary downstream?

Load varies downstream primarily due to the following reasons:

Traffic Flow: Downstream, the traffic volume usually increases as more vehicles join the road from different interchanges and entrances. This increased traffic volume leads to higher load on the network.

Congestion: Congestion can cause load variations downstream. When a section of the road becomes congested, it causes vehicles to slow down and queue, leading to increased load on that segment. This congestion can ripple downstream, impacting the traffic flow and load in subsequent sections.

Accidents and Incidents: Accidents and incidents can also cause load variations downstream. These events lead to lane closures, reduced lanes available for traffic, and potential diversions. This disruption in traffic flow results in increased load on the downstream sections.

Lane Changes and Merging: Lane changes and merging points introduce load variations downstream. As vehicles merge or change lanes, it affects the traffic dynamics, causing speed adjustments, lane congestion, and increased load.

Signalized Intersections: Signalized intersections can introduce load variations downstream due to the stop-and-go nature of traffic. When vehicles stop at a red signal, they occupy space on the road, creating congestion and increasing load on the downstream segments.

On/Off Ramps: On/Off ramps can also lead to load variations downstream. When vehicles enter the highway from an off-ramp or exit the highway using an on-ramp, it influences the traffic flow and load on the downstream segments.

Lane Drops: Lane drops, where the number of available lanes decreases, can cause increased load downstream. Traffic merges into fewer lanes, resulting in slower speeds, congestion, and higher load on the downstream sections.

Demand Variations: Downstream, the traffic demand can vary based on factors such as time of day, events, attractions, and destinations. These demand fluctuations impact the load on the downstream network.