6.2.4. Network

Transport network consists of roads, junctions, bus stops, rails, railway station etc. Normally road network and rail network are represented separately.

Transport networks are essential as they are the routes and structures that facilitate transportation. In a city or region, these networks include not just the roads and pathways but also other elements like bus stops and train stations, which help people move around. The road network and rail network are usually studied separately to better understand each system's characteristics and complexities.

Think of transport networks like a city’s circulatory system. Just as veins and arteries transport blood (or nutrients) to different parts of the body, transport networks carry people and goods to various locations.

Road network is considered as directed graph of nodes and links. Each node and links have their own properties. Road link is normally represented with attributes like starting node, ending node, road length, free flow speed, capacity, number of lanes or road width, type of road like divided or undivided etc.

In transport modeling, the road network can be visualized as a directed graph where junctions (nodes) and the roads connecting them (links) have specific characteristics. Each road link is described by various properties such as where it starts and ends, its length, how fast vehicles can travel on it under ideal conditions (free flow speed), how many vehicles it can accommodate at once (capacity), and its physical layout (number of lanes or type of road).

Consider a road as a river: the starting node is where the river begins, the ending node is where it flows into another body of water, and the width of the river (like the lane number on a road) determines how many boats can travel on it simultaneously.

Road junctions or nodes are represented with attributes like node number, starting nodes of all links joining the current node, type of intersection (uncontrolled, roundabout, signalized, etc.).

Junctions or nodes in a transport network function as critical points where roads converge. Each node is assigned a unique number and is described by the incoming links that connect there. The type of intersection (like a roundabout or stoplight) affects how traffic flows through these points and is crucial for traffic planning and safety assessments.

Think of road junctions like the points where several roads meet, similar to a busy marketplace where different paths converge. Depending on how entry is managed (like who gets to go first), the crowd can either move smoothly or become chaotic.

Similarly public transport network like bus transit network and rail network are represented, but with attributes relevant to them. These may include frequency of service, fare of travel, line capacity, station capacity etc.

Public transport networks, including buses and trains, have their own set of attributes that define their service quality and efficiency. Attributes such as how often services run (frequency), what passengers must pay to use the service (fare), how many passengers a line can carry at once (line capacity), and how many people can be accommodated at a station (station capacity) help in evaluating and improving transport service.

Imagine the public transport system as a restaurant. The frequency of service corresponds to how often the restaurant is open, the fare is like the price of a meal, and the capacities reflect how many customers can be served at once. A well-managed system ensures there are enough seats (capacity) and frequent service (similar to having plenty of staff available to serve customers) to meet demand.

This completes the inventory of base-year transportation facility.

The assessment of the transport network ends with the compilation of an inventory of base-year transportation facilities. This inventory serves as a foundational dataset for analyzing current transport systems and planning future improvements, ensuring that all relevant data about roads, public transport nodes, and their attributes are accounted for.

Think of this inventory as taking stock of all items in a warehouse before deciding what to buy or sell next. Without a clear understanding of the available inventory, one can't efficiently plan for the future.

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