At the last crack of the bat, the crowd pours out of Wrigley Field and into the neighborhood. Do you know how long it takes to get Wrigleyville back to normal?
TRAF-NETSIM knows. Or, more accurately, Michelle Thomas, an associate at Barton-Ashman Associates Inc. in Evanston, can manipulate the computer program to show how long it will take for the cars to leave, for a post-game CTA bus to move through the area and for the pedestrians to clear the streets.
“Volume is an input, and we can work from there to show it all in pictures,” said Thomas.
Actually, post-game crowds are small potatoes for NETSIM, one of about 50 programs highway planners and designers now use to uncomplicate a tedious job that used to be done by hand in ink.
NETSIM is a continuously updated program developed by the Federal Highway Administration. It is capable of very detailed traffic-operation analysis, Thomas said.
She uses NETSIM to show how efficiently cars and trucks will move on a highway-in a two-hour period of rush hour, for example-and how well the highway will function in 20 years, which is as long range as highway planning can be because of the less predictable faster-paced growth patterns.
Some of the computer-generated simulations that designers use to piece together the big picture for highway projects are:
– Projected population growth and directions of growth.
– Noise, drainage and air-quality data relevant to routing highways around wetlands and historic sites.
– Interactions between highways and mass-transit systems, waterways and airports.
– Current traffic-safety trouble spots and what they’ll look like in several years.
– The number of expressway interchanges and the weaving patterns of cars entering and exiting the highway.
– When and where job-related trips will cause congestion.
This gives highway planners and designers a clear idea of when and where rush-hour traffic will cause stop-and-go congestion. Their computers can help them design highways from Level A, which ensures no congestion at any time, to Level F, a commuter’s hell on wheels. The experts say the only hitch to building the best is paying for it. The taxpayers would never approve it, they say.
“Level A and B are never used as the basis for building roads because they are too costly,” said Ken Patchen a senior associate at Barton-Ashman. “Most roads are built to Level D level of service. Level F roads incorporate a high rate of congestion, and they are cheapest to build.”
Thomas said that when the less sophisticated programs reach Level F congestion, “the computer just shows a star and won’t provide analysis. Evidence, perhaps, that some computer programmers are also commuters.”
Jerry Daleiden, IDOT’s information services manager for District 1, which includes Cook and the five collar counties, said it’s easy to understand how the computers work if you remember studying for high school biology.
The program is called Computer-Aided Design and Drafting, or CADD. “CADD looks like two large color monitors, and the information it organizes is like the clear plastic overlays in a biology text that show the muscular system, the vascular system, whatever, laid over the human body. For our purposes, CADD shows pavement and pavement markings, where the trees are, where the traffic signals are, and we can mix and match the pages for the right amount of detail,” said Daleiden.
The point is, he added, that CADD keeps a project from becoming too complex. Unnecessary layers can be turned off. And all of the symbols-for trees or fire hydrants, for example-are standard and easily recognizable by contractors.
CADD also facilitates changes. “No more erasing,” said Daleiden. “We used to do the plans in ink, and it was difficult to erase and make changes. Now we just tell the computer to send out a new original of the drawing.”
The drawings are based on surveys of existing conditions stored in field equipment and transferred to an office computer that produces a picture.
“Prior to computers, it all used to be done by hand,” said Ken Macander, a 30-year IDOT veteran and bureau chief of design for District 1. “The surveyor brought back the information, the draftsmen drew things up, and the engineers did the figuring with desktop calculators, tables and books. We used charts to map out gutters, 10-foot or 12-foot lanes, where traffic lights went, everything.”
Macander said that though he likes the speed and efficiency of computers, he dislikes the attitudes that the machines have engendered in some engineers.
“I see some people treating the computers like gods. Because the computer said it, it must be right. But we will always need individuals with the know-how to tell whether the result is reasonable, to recognize whether bad data has been fed in,” said Macander.
Richard J. Hocking, vice president at Barton-Ashman, said the computer will be an important factor only as long as it isn’t the main focus of highway planning and design.
“The people have advanced even more than the machines,” said Hocking. “We have much better trained people now, and that’s important because judgment will always be the critical factor.”
“None of these computer programs are perfect representations of reality, but they all give you a rough idea of what goes on,” said Joseph Schober, director of research at Northwestern University’s Transportation Center, Evanston.
Jotin Khisty, a professor of civil engineering at Chicago’s Illinois Institute of Technology, said “The best thing about the computer is that it gives us more time to analyze.”
He referred to the computer as a “timely godsend” because highway-design programs became available at about the time suburbanization and rapid population growth multiplied the complexities of the planning process.
“People used to plan for congestion only in the downtown areas, but now it’s equally bad in the suburbs. The jobs and the shopping (now are) spread all over,” said Khisty.
Tracking these kinds of changes is addressed by the geographic information system, a software package that includes information from the U.S. Census Bureau and other government agencies. It documents physical characteristics and provides information on population and the environment. Hocking said it’s one of the most useful software packages used at Barton-Ashman.
“(Geographic information system) has been absorbed now by most planning agencies. Considering the amount of information we need to manage, keep track of and eventually use, it gets rid of a lot of tedious work,” he said.
Reducing the tedium and complexity of the work also is the point of sketch planning and quick-response techniques, said Khisty. Sketch planning provides a rough, undetailed simulation that lets highway designers explore the viability of a plan before the investment necessary for full implementation. Once the value of the plan is known, detail can be added as commitment to the plan increases.
Quick-response techniques are five simplified models. They are used instead of sequential models, which run one after the other on a mainframe computer in a costly operation. In addition to providing answers fast-less than a week in the case of a large city-they also can operate on personal computers.
Speed is always a factor in highway planning and design because the complexity of the work makes most tasks time consuming, even with high-powered computers and sophisticated software.
To produce a preliminary design, a complete draft and an environmental report for the 16.9-mile Elgin-O’Hare Expressway, for example, Barton-Ashman needed 30 months, Hocking said. It took another year to finish the final report. And the federal government’s review and approval process took about four months.
“That’s pretty quick,” said Hocking, referring to the government’s review. He added that the Elgin-O’Hare project was larger than average and it was more complicated than most because of O’Hare-related issues, such as airport development and runways.
Soon the Elgin-O’Hare Highway, which still is under construction, will be part of a roadway system that IIT’s Khisty said is “probably the best in the world.” Today’s planners and designers are contributing to a transportation system whose foundation is the 42,000 miles of interstate highway that was built after World War II.
“It was the largest civil project ever undertaken,” said Khisty. “Building highways was very important work in the United States, and it still is.”
The work of these computers isn’t stopping with the planning of highways, either.
According to Northwestern’s Schober, computers “are a neat way to test new technology.”
As an example, Schober cited the automated vehicle identification model, which simulates an alternative way to pay tolls. The car would slow down long enough for an identification badge or sticker to be recognized as it passed the automated booth, and the driver could be billed at the end of the month.
Other equally high-tech simulations are part of the Intelligent Vehicle Highway System, which Schober called “an unfortunate name for a large scale experiment that uses computer and information technology to operate ground transportation systems.”
The project is directed by a partnership of the highway administration, the Illinois Department of Transportation, and Motorola Inc., Schaumburg. The model building is provided by experts at Northwestern University and the University of Illinois at Chicago.
One of these models experiments with possibilities for providing travel information to homes or roadside kiosks. Another incorporates computerized maps and navigation systems for use in private vehicles so cars would always know where they were and could choose the most efficient path to their destinations. In this system, a computer would tell the driver when to turn left or right.
Eventually, Schober said, he sees several thousand privately owned vehicles participating in a test of the system so “very hot data will be coming back from the cars to a central location and we can see how and how efficiently people are moving through the system.”
Perhaps the most far-reaching model is the automated vehicle control system, which requires specially equipped cars and a roadway that would take over for the driver. While on an access ramp, the car would be tested. If its systems were up to par, the car would move onto the road, which would merge it into traffic, maintain standardized spacing between vehicles, deliver it to the correct exit ramp and safely move it off the highway.
“People are spending real money to develop these concepts,” said Schober.
———-
Next week: How computers are being used in the roads to ease traffic congestion.
