Traffic microsimulation tops the list of a transportation engineer’s favorite planning tools. By using animation to model the behavior of individual vehicles on a specific road network, microsimulation makes it possible to predict how changes in a roadway alignment, intersection configuration or ramp connection will impact traffic flow.

Microsimulation can be incredibly valuable when replicating the roads that surround an airport, which can mimic those of a busy, crowded, congested downtown area. Cars continuously pull up to curbs and sit for minutes while passengers load or unload, while shuttles dropping off or picking up passengers have their own distinctive patterns. Space must be carved out to accommodate all types of transport, including cabs and ride shares, as well as drivers who wish to park.

Add in the reconstruction of major airport passenger terminals, and you have created a master class-level traffic microsimulation challenge — one whose models must consider everything from current construction activities to the time it takes the average traveler to unload a suitcase.

We’re experiencing this challenge firsthand at New York’s LaGuardia Airport, which broke ground in August 2017 on a 10-year project to replace the existing Terminal C and D with a single state-of-the-art terminal. It’s part of a major overhaul LaGuardia Airport is undertaking while continuing to serve nearly 30 million passengers a year.

One of our jobs at LaGuardia right now is to keep vehicles moving smoothly around Terminal C and D throughout construction. That has involved not only modeling traffic patterns but also the interaction between pedestrians and vehicles, taking into account all the ongoing design changes that have the potential to impact flow, both now and in later phases of construction.

Transportation Planning Transformation

Simulating the construction’s changing impact on airport ground transportation is something that would be virtually impossible to achieve without today’s most advanced microsimulation modeling tools, particularly at the level of sophistication required here. But complex projects like the one at LaGuardia also demonstrate the value these relatively small investments can have on the success of transportation projects of all shapes and sizes.

The microsimulation models we create, for example, can be used to provide compelling evidence of a design alternative’s effectiveness to a skeptical public audience. By simulating future scenarios, they also can be used to predict the configurations that will work, proactively troubleshoot solutions to traffic problems, avoid costly design mistakes and manage the roadway user's expectations.

Microsimulation is only one of several technologies that are changing transportation planning.

Our transportation engineers also utilize TransCAD, geographic information systems-based  (GIS-based) modeling software that predicts how land use changes will change traffic volumes. For example, the addition of a new residential development may increase demand on an intersection, ultimately resulting in the need for additional turn lanes. Data from TransCAD can also be used in microsimulation modeling to identify new roads that might need to be added to the regional transportation network to accommodate new development.

Recently, we started using modeling software in conjunction with OpenRoads ConceptStation, software that rapidly creates conceptual designs of roadways, intersections and bridges. Using ConceptStation, our transportation engineers can provide stakeholders with an early look at their conceptual design options in three dimensions.  These movie-like depictions, which include real-world data and cost analysis, can be assembled in as little as a week, compared to the months it can take to complete preliminary 3-D animation using traditional methods. 

The data-driven technologies now used in transportation planning, in other words, are more robust and intelligent than ever. Complex projects can’t be completed without them. But they deliver value to simpler ones as well.


See how we're using this technology to keep travelers moving during construction of the Delta terminal at LaGuardia Airport.


Paul Plotas is a transportation department manager at Burns & McDonnell. He has more than 30 years of experience in traffic engineering design and transportation planning including traffic impact studies, corridor studies, pavement marking, traffic signals and more.