Streams – Basics

Definition

A stream is the path on which a set of vehicles travels from the start to the end points of their journey. In MSV, a stream is a sequence of ‘Way’ objects. A stream does not necessarily use all lanes of each Way it passes over—it can use one or more lanes from each Way object it includes. Streams can overlap each other, as they can share whole or parts of a Way beneath them.

Appearance

A stream is shown as a strip, colored gray, with two quads (squares) at its start and end points. The quads have arrow marks to indicate whether they are at the entry or exit side of the stream. Each quad also bears the name of the stream, as set in the editor.

Category

Streams can belong to one of the following categories:

• Vehicle Streams: For which modal split (percentage of each type of vehicle) is specified.
• Cycle Streams
• Bus Streams
• Pedestrian Streams

Flow

Each stream has a flow value, which represents the number of vehicles per hour per lane (on the very first Way it is comprised of). As the stream progresses, its width may decrease or increase depending on the Way objects it passes through. Vehicles will restrict themselves to moving within this imaginary boundary of the stream rather than the road beneath. Consequently, any lane changes can only occur within the stream's width and not beyond its bounds.

Vehicle Behavior

Vehicles on a stream can be set to follow one of two behavior types modeled in MSV:

• Lane-Based Behavior: Vehicles follow lane discipline, changing lanes as and when required, given favorable conditions.
• Space-Based Behavior: Vehicles tend to use available space in front and on the sides whenever required and wherever possible. This is common in chaotic traffic environments seen in cities and towns of developing countries, where dozens of vehicle shapes, sizes, and speeds exist. Lane discipline cannot be implemented due to their physical and operational properties.

In developed countries, lane-based movement can change to space-based behavior during disaster or event management scenarios, where rush or racing behaviors emerge.

Speed

A maximum speed (limit) can be set for each stream. This limit can be based on field observations or set for scenario testing and impact measurement purposes.

All these settings can be configured using the Stream Editor.