Under the Hood: From Airports to Intersections, Using Mobility Simulation to Improve Multi-Modal Traffic Flows

Andy Manze March 5, 2019 5 min read

Every month, an Autodesk expert gets technical and provides an overview of the AEC Collection’s most powerful workflows. Read on to learn how you can simulate pedestrian and vehicular traffic flows using Mobility Simulation, an integrated multi-modal simulation engine for InfraWorks.

The United Nations predicts that by 2050, 2.5 billion more people will live in the world’s cities and urban centers, and they will drive 2.9 billion additional vehicles. With two out of three people on the planet getting around cities on foot, bicycle, car, bus or train, the potential for commerce-crushing congestion and gridlock will be at an all-time high. Today’s challenge is to design and build infrastructure that promotes both safety and mobility during a period of rapid population growth.

Luckily, designers and project planners can get unprecedented insight into these challenges with mobility simulations. Mobility simulations model how people and vehicles move around in a transportation network. The network could be within an airport, stadium or other activity hub where people congregate, form lines and travel to and from points of interest. Traffic on roads and highways follow similar patterns as vehicles enter and exit major through-ways, queue at intersections and slow to a crawl around accidents. A mobility simulation can visualize how people move during a trip, from start to finish, and predict where there will be problems. This gives transport analysts insight into how each individual impacts the transportation network as a whole.

The beauty of a sophisticated model is the ability to incorporate multiple modes of transportation within a network. At an airport, for example, airplanes, passenger cars, taxis, transit buses, commuter trains, and airport transit systems transport people to and from the airport itself, ticketing, boarding gates, concourses, customs, baggage claims, and food and beverage courts. The model lets transport analysts change various design details to optimize flow, minimize wait times, and maximize safety.

Let’s look at some examples of how mobility simulation can improve the design of a transportation network.

People Movement: Understanding Crowds in Stadiums and Transport Hubs 

Anywhere people gather in large numbers, mobility can quickly deteriorate, posing serious safety risks during peak traffic. From vehicular traffic leading to stadium parking and loading/unloading zones, to lines of people waiting for tickets, seating, concessions and restrooms, the ability to predict movements and change patterns can not only enhance the user experience but also avoid safety incidents. A model quickly shows the best way to move around the network, and where modifications such as lane funneling, turnstiles or tunnels would improve flows.

Passenger traffic patterns can get particularly complicated at international airports. Automated kiosks for ticketing or passport control can be both a boon and a bane, depending on whether all kiosks are fully functional. Delays at these and other checkpoints can cause passengers to miss flights, creating longer queues at customer service counters. To model various scenarios, you can identify parameters such as predicted passenger paths, estimated travel speeds, alternative routes, and unexpected behaviors in the face of obstacles.

By creating various scenarios, you can try creative solutions to some of the toughest mobility challenges at airports, stadiums, convention centers, performing arts centers, fairgrounds and other public environments.

See it in action: Watch this video simulating the mobility of people in line at an airport border control point.

Vehicle Movement: Improving Traffic Flow With Mobility Simulation

Despite the future trend toward driverless cars, peer-to-peer ridesharing and walk-bike-ride mobility in smart cities, automobile sales are still rising. Some analysts predict that today’s 1.2 billion global car fleet will double by 2030. More than half of these vehicles will be operated in cities, causing unprecedented congestion on transportation networks that were not designed for such high volumes of traffic.

While the transportation sector builds out capacity, it is also shoring up our existing networks to maintain safe and efficient mobility in and around our cities. Mobility simulation is an indispensable tool for predicting and improving traffic patterns. Consider the example of a four-way intersection where vehicles waiting to make turns routinely stack up. A traffic analysis and traffic simulation could reveal that a roundabout would be a cost-effective design alternative.

See it in action: Watch this video to understand traffic movements at a busy four-way intersection, revealing that a roundabout would be the design solution.
How to simulate traffic movement in Infraworks 

To create a simulation of traffic patterns at a troublesome intersection and evaluate alternative design options, take these steps:

  1. Use the model builder in InfraWorks to create a base model.
  2. Create new proposals for each design alternative (existing layout and roundabout). Each option should be in a separate container.
  3. Use the InfraWork’s built-in road and junction modeling tools to model each option.
  4. Define the study area, which pushes traffic into the intersection.
  5. Open the traffic analysis panel to change the way traffic flows into the intersection. Adjust traffic demand values such as volume and direction.
  6. Run simulations with various settings, then compare results viewed as numerical reports or as infographics in the InfraWorks 3D model.

Multi-Modal Movement: Taking Into Account All The Ways Of Getting Around

It’s a rare city that doesn’t have cars and trucks, transit buses, passenger and freight trains, commuter rail and trams—all sharing the transportation network that moves people and cargo to multiple destinations. Urban planning poses the unique challenge of meeting the needs of wildly different travel demands. The variables can include speed, carrying capacity, comfort and cost, and the interplay among modes of transportation create even more variables.

To build and maintain a safe, convenient and economical transportation system, planners need to do door-to-door analyses that establish the traffic flows through every mode. Modeling a journey taken using various transportation options gives a complete picture of how this complex network operates. A multi-modal analysis thus simulates people movements through different modes of transport, including walking distances, passenger vehicles and public transport services such as trains and buses.

Urban Mobility is of growing importance to many cities.
How to Create a Multi-Modal Mobility Simulation

Working in the InfraWorks Mobility Simulation window:

  1. Build the network with the rail, road, and walkway layout tools, including all connections and crossings.
  2. Add the stands for people to congregate on while waiting for a service.
  3. Add the people areas to define the journey origins and destinations.
  4. Add the zones for traffic origins and destinations.
  5. Schedule the train/bus services running on the network.
  6. Define the demand matrices or traffic volumes.
  7. Generate the trips and run the simulation.

Mobility simulations create realistic visuals and real-world movements to ensure safe and free-flowing travel in any environment. Multi-modal simulations generate the real-time data you need to make difficult design decisions. Using these tools, you can see the impact of design decisions on pedestrian and vehicular flow, and so deliver more effective solutions for future travel demands.

Learn more about the Mobility Simulation engine for InfraWorks with these Autodesk resources:

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