mobility

Towards Ethical and Transparent Mobility Data Products: Estimation of Road traffic Metrics from Publicly Available Camera Feeds

Human mobility reflects important characteristics of human behavior, which serves as a critical moderator among the social, economic, and environmental systems of cities. To understand mobility and its implications, reliable mobility data products are required, among which road traffic metrics such as traffic density, flow, and speed are often needed. Today, road traffic metrics have been widely applied in various areas, including routing, commuting, transportation planning, as well as the study of accessibility, traffic emissions, and social/environmental justice.

As stated by statistician George Box, “all models are wrong.”[1] Data, an artifact of models and algorithms, unarguably have their imperfections. In the production of mobility data (especially big data), errors, inconsistencies, and biases are likely to be introduced by the algorithms involved in the data lifecycle. To ensure that ethical decisions can be made when applying these data for other purposes, the transparency in the lifecycle of mobility data needs to be highlighted. The production of mobility data should be observable by human subjects so that the uncertainties of data can be inspected and audited, and the consequences of data applications can be examined and fully revealed.

The current focus of our work is to facilitate the transparent and ethical production of mobility data, or more specifically, road traffic metrics. The publicly available traffic camera data are used to implement this study. Today, traffic cameras have rapidly emerged as a primary data source for transportation management and control, particularly in the United States and Canada. Real-time images from these cameras are typically available to the public through States’ Department of Transportation, which are free from the restrictions to access, distribute, and create derivative works from the data. The openness of traffic camera data makes them well suit the purpose of this work.

Figure 1. Traffic cameras and images in Central Ohio obtainable from OHGO.

The quality of the road traffic metrics derived from the camera feeds is highly dependent on the accuracy of the identified vehicles. While many effective vehicle detection methods (e.g., YOLOv4, RetinaNet) have been developed recently, their accuracy varies significantly among different camera configurations and environments, especially for vehicles appearing small on the image. In this work, a quadtree-based algorithm is developed to continuously partition the image extent until only regions with high detection accuracy are remained. These regions are referred to as the high-accuracy identification regions (HAIR), which are then used to derive reliable road traffic metrics such as traffic density.

While the use of HAIR can significantly enhance the estimation of road traffic metrics, it also brings errors because of using unrepresentative image inputs or a low level of partitioning. We explicitly present such errors by introducing an accuracy measure called the regional average precision, which helps to actively inform the end users of the potential uncertainty of the data. The data sources, algorithm, code, and the derived data products are made accessible to the public through an online computational platform called CyberGIS-Jupyter. This will not only facilitate replicating the data production in different areas, but also enable the in-depth examination of how uncertainty in the data may have unintentional societal impacts.

[1] Box, G. E. (1976). Science and statistics. Journal of the American Statistical Association, 71(356), 791-799.

 

Yue Lin, PhD Student

The Department of Geography

The Ohio State University

 

A First Step

I’m not a geographer by training or by discipline. I do have two Bachelor’s degrees in the following majors; Criminology, International Studies, Russian, and Political Science. I also have a Master’s degree in Public Policy and Administration. This doesn’t mean a whole lot, but what it does mean is that, there are certain issues that I’ve looked at through varying lenses depending on what discipline you’re talking about. As an example, policing and law enforcement in Criminology, Political Science, and Public Policy vary on methodology, cause and effect, history, and how to move forward depending on which one or which class you’re engaged in. The Cold War is different when you investigate the perspectives from an international relations lens versus a purely Russian cultural lens. None of them are wrong but none of them are 100% correct either. We, as human beings, engage in our world in different ways and the impacts of those actions snowball to coalesce into a much larger picture. If nothing else, what these varying disciplines have taught me is to think critically, think outside the box, and never to accept the given status quo.

Now, you would think, that something as simple as counting people would be – just that – simple. However, that is far from the case.

Yes, from a political science perspective, the census is written into the Constitution of the United States and accounts for distribution of representation across the country. The short answer about what the census is, can be wrapped up in a nice little bow by the following video.

However, the reality of the Census, is something much more complicated, long-lasting, and carries with it the ability to change our nation on a fundamental level. As the representation shifts across the country with each census count, the outcomes determine not only votes in the House of Representatives but resources distributed, prevailing ideologies, future political, social, and economic policies, and electoral college votes. Many people look at the census as a benign exercise and means very little the them personally, after all, it has little impact on their individual day to day lives.

The exact opposite is true. Maybe it’s the political science or public policy speaking, but for me, the fundamental importance of the census is the basis for everything else. The census is the first step in our nation deciding what type of country we want to be, what we value, and what is important to us. The census allows the voters to decide what type of leaders we send to Washington, and what the priorities are for the future.

The census is not the last step or the only step in changing our country and making it better, but it is the first. The first in a long line of standing up to be counted, and of encouraging the same of others – even against their fear and the prejudice they may face. The census is a call to action for anyone who is or isn’t happy with the policies being enacted on their behalf. If you ignore the call and are not counted, you are doing a disservice to yourself, your neighbors, and your community.

What does any of this have to do with Geography?

Great question! If you’re not a student of Geography-like me-, you’re not the only person asking it.

Geography is a varied discipline that encompasses not only cartography and maps, but the study of what makes those maps what they are, why people are where they are. It encompasses sustainability, mobility, climatology, social justice issues, immigration and migration, as well as land use. What does all this mean?

Well, the population isn’t spread evenly across the country. We’ve all seen the red and blue maps on election nights and how the distribution of those populations have an impact on viewpoints, ideologies, and politics. We know that the country is divided in their way of life: urban and rural. These divides correlate to race, economic status, education, and a whole host of other demographic markers that can be identified. We’ve also seen how the policies of our government impact land use, our national parks, and the regulations enacted to protect citizens from harmful pollutants. Becky Mansfield’s post regarding EPA deregulation is a great example. In Geography, not only are these issues discussed but form the foundation for critical thinking along lines that focus on the world around us and our impacts on it. The census, either directly or indirectly, has an impact on all of us. And in the end, what this all amounts to is power. Who has it? Who should get it?

We are at a critical stage. The U.S. Census bureau will end counting efforts on September 30th (a full month early), according to NPR. This means that if you hadn’t already filled out the questionnaire online, then your time is running out. You don’t have to go anywhere or talk to anyone to complete your census entry. It is the easiest first step to being a part of the process of representation you can ask for. Now is your chance to step up and be counted, just click the link below.

 

 

Suzanne M.S. Mikos

Department Manager

Department of Geography & Center for Urban and Regional Analysis

 

References and Links:

Sustainability in a World of Cities

The 21st century witnessed an epochal event in human civilization: in 2008, the world became majority urban for the first time in history. Urbanization is accelerating: two-thirds of the global population will live in cities by 2030. Some scholars are projecting an essentially urban planet by the end of the century, with 90% of the world population crowded into urban areas.  A world of 10 billion people living predominantly in cities— of which 60% globally have yet to be built —underscores the critical need and immense opportunity for new scientific and policy approaches that can achieve sustainable urban systems.

graphic to demonstrate CMAX Bus service after 6pm

Figure 1: Locations reachable at 6pm on a typical weekday from the Linden neighborhood of Columbus by public transit and walking after new CMax bus rapid transit service. Graphic courtesy of Harvey Miller

Mobility is central to urbanity: transportation is how we organize our cities. While the personal automobile has generated stunning levels of travel and activity over the past century, it has also led to urban transportation systems being inefficient, costly, inequitable, unsafe and unhealthy, and damage environments at local to global scales.  This is leading to a mobility crisis that will get worse as the world continues to urbanize.

In many cities, we are seeing the deployment of new technology-enabled mobility services such as vehicle sharing, hailing services, and micromobility such as scooters and bikeshare systems. These innovations are disrupting the mobility landscape of cities, with even larger disruptions inevitable with the coming of connected autonomous vehicles.  While these hold promise, they also may make an unsustainable situation even worse.

Are New Mobility Technologies Sustainable?

Introducing disruptive mobility technologies to cities is a large-scale, real-world experiment that will impact cities for decades. The outcomes of these mobility disruptions have profound implications for urban air quality, social equity, energy consumption, greenhouse gas emissions, safety and health.  So far, the evidence is mixed. For example, some evidence suggest that Lyft and Uber are reducing drunk and impaired driving (although possibly at the expense of heavier drinking).  However, these services are also increasing traffic congestion, undermining public transit and leading to higher energy consumption and emissions.

graphic example of data dashboards from available data

Figure 2: The Columbus Urban and Regional Information Observatory (CURIO) – a geospatial data dashboard for Columbus, Ohio. Graphic courtesy of Harvey Miller

Whether new mobility services will make cities more sustainable is an open question, one that will be difficult to answer using 20th century urban scientific and management approaches.  In the past we have relied on simple data and measures that could be easily collected.  For example, automobile traffic counts have been easy to collect: consequently our main transportation performance measure is how many vehicles we can shove through a network.  Our simple, 20th century models also treat mobility as undifferentiated flow, like water – consequently, we made traffic congestion worse by trying to build bigger “pipes” because of a phenomenon known as induced demand.

In the 21st century, we need transportation measures and analytics that:

  • i) focus on people and their activities, not vehicles and their movements;
  • ii) recognize the heterogeneity of peoples’ needs and capabilities with respect to mobility and accessibility, and;
  • iii) capture the full cost of transportation, especially externalities such as emissions, noise, risk and other social and environmental impacts.

New Geospatial Technologies and Sustainable Mobility Science

New sources of data are emerging that could enable some of this system science. Location-aware technologies such as mobile phones and global position system (GPS) receivers, environmental sensors, social media and smart technologies are generating data at unprecedented volumes and spatio-temporal resolution, facilitating new insights into mobility patterns and urban dynamics.  The cost of data storage has plummeted, allowing these data to be saved and archived over time.  Advances in machine learning, geospatial data mining, geovisualization and other knowledge discovery techniques are helping specialized and siloed practitioners work together to make sense of this data avalanche.  Cloud computing, geospatial data portals, application-programming interfaces and data dashboards allow scientists to share these data and information widely with the public. These new technologies are creating a new kind of data-enabled and computation-rich mobility science that can lead to more nuanced, appropriate and sustainable solutions to our growing urban mobility crisis.

Harvey Miller

Bob and Mary Reusche Chair in Geographic Information Science

Professor of Geography

Director, Center for Urban and Regional Analysis (CURA)

 

Some of the geospatial data-enabled sustainable mobility research projects conducted in the OSU Department of Geography and the Center for Urban and Regional Analysis (CURA) include: