Keeping up with traffic
The Minnesota Traffic Observatory focuses on Twin Cities highways
By Charlie Plain
April 22, 2008
Hoping to help keep Twin Cities freeways flowing smoothly, the University of Minnesota's Department of Civil Engineering has made a move of its own. The department recently opened the doors to the new Minnesota Traffic Observatory, a world-class lab featuring innovative technologies to help researchers design roadways that are safer and easier to drive. The Observatory is a joint venture between Civil Engineering and its campus neighbor, the Center for Transportation Studies.
A new point of view
"The idea of an observatory is that it brings the universe to your eyes," said lab director John Hourdos. The Minnesota Traffic Observatory takes an alternate view of the universe by looking closely at cars on the ground instead of stars in the sky. The new facility is designed to see vehicle traffic around Minneapolis and St. Paul as the interrelated sum of its parts. "We are looking at traffic as a system," explains Hourdos. "As congestion increases, there are no isolated interchanges. The whole thing is a big unit." Getting the big picture for local traffic will help researchers identify dangerous or inefficient sections of the network and fix them. Employing state-of-the-art technologies like computer simulators, high-speed networks and video projection equipment, the lab creates an all-encompassing sensory experience of the Twin Cities traffic system.
"Researchers, students, and visitors who come here will get a more complete picture of the transportation network," said Hourdos.
It's all under control
Hourdos, along with principal investigator Gary Davis and engineers Ted Morris and Chen-Fu Liao, set up the core of the Observatory to form a working virtual traffic control center. At its heart is a cluster of computer workstations lining two long counters connected to live traffic sensors and simulation systems. The workstations sit within easy viewing of live traffic video displaying across a wall. Lighting up the video wall is a fiber optic line connecting the observatory with the Minnesota Department of Transportation's (Mn/DOT) traffic operations center. Located in nearby Roseville, the center monitors freeways around the Twin Cities metropolitan area. The fiber optic line provides live feeds of up to 16 of Mn/DOT's 320 surveillance cameras watching the roadways. Before the addition of the fiber optic line, researchers relied on day-old recorded and compressed video. The low resolution footage wasn't ideal for close inspection by engineers.
"With high-quality video, we can use machine vision detection systems to analyze traffic," said Hourdos. Such systems can count how many vehicles pass a specific point as well as measure their speed, length and the separation between them. But Mn/DOT isn't providing the observatory with the only sights to be seen. High above downtown Minneapolis, the lab has exclusive access to a view unlike any other in the world.
Mounted to the rooftops of three high-rise buildings are an array of cameras maintaining a close watch on the most accident-prone intersection in the state: the I-94/35W commons. "The setup doesn't exist anywhere else in the world at such a convenient location," said Hourdos. "The fact that people are crashing is bad, but as researchers, we're delighted."
"The idea of an observatory is that it brings the universe to your eyes," said Hourdos.
The platform communicates wirelessly with the Observatory, transmitting data from video cameras and a special instrument called the "Autoscope." A sort of smart camera, the Autoscope was invented by Professor Panos Michalopoulos and is manufactured by Image Sensing Systems, Inc. of St. Paul. Behind the traffic control consoles is what the lab's staff calls the "DEN," which is short for "Digital Environment." The DEN works like a personal 3D theater where test volunteers and engineers use virtual reality technology to evaluate intersection designs or driving situations.
The system is made up of three large projection screens that are used to surround a person standing inside the DEN. A bank of six computers control what the user sees, while a traffic simulator feeds the system with realistic traffic conditions. Inside the DEN, test subjects and any equipment they use are wired with sensors to relay their movements to computers. The digital visualization tools then alter the computer-generated scene in response to their movements, allowing the subjects to interact with their virtual traffic environments.
According to Hourdos, the 3-D environment can be programmed to create scenes designed to be driven through or walked on foot. The final innovation of the MN Traffic Observatory is perhaps the most revolutionary. "A brand new thing we have in this lab is another way of visualizing the system. It's what I call the GIS/MAP Table," said Hourdos. Approximately the size of a large conference room table, the GIS/MAP Table projects maps onto its surface.Hourdos wanted to marry the spaciousness of a traditional drafting table with today's modern GIS and computing technology.
Hourdos wanted a way to examine maps in detail without giving up a wide perspective. The GIS/MAP table affords both advantages with a few additional tricks thrown in. Users of the table control it with a stylus, just like with a personal organizer or Palm Pilot device. The stylus acts as both a pen and input device, allowing researchers to write notes on the maps as well as manipulate them. The electronic table then saves any notes or changes for later access. With all of its clever engineering and new technology, the Minnesota Traffic Observatory provides a fresh perspective on some of highway transportation's biggest problems.
As traffic around the Twin Cities increases, it's getting hard enough for drivers to keep an eye on traffic on their own. Thankfully, the University of Minnesota will be along for the ride.
From Civil Engineer, a publication of the Department of Civil Engineering in the Institute of Technology.