The woman's voice entreats you.
"In 500 feet, make a U-turn if possible."
You ignore the voice. It grows higher in pitch and louder in volume.
"Please make a U-turn NOW!"
You ignore her again, and drive onto Interstate 57 at Curtis Road.
You do this without the help of the disembodied voice in your GPS unit because it doesn't know there's an interchange at Interstate 57 and Curtis Road.
Neither does Google Maps. Or Mapquest. Or, heck, the Illinois Department of Transportation.
Increasingly, travelers rely on online mapping services or portable satellite-driven GPS units to get where they're going. But when a new street is built – or a new interchange opens on an interstate highway – it can take some time for that street or exit ramp to appear on a map anywhere.
The Curtis Road interchange opened last May. It will probably appear on maps some time in 2009.
"Technology's a wonderful thing," said Cameron Moore, executive director of the Champaign County Regional Planning Commission. "But all that information has to be loaded into software.
"It's more complicated than it sounds."
Moore heads an agency that might have the only correct map of Champaign County. The commission is home to the Champaign County GIS Consortium, an intergovernmental group that creates electronic files for use in mapping software.
Some of the major mapping services that provide data to the online sites and GPS companies buy the consortium's data, Moore said. But those companies haven't made their latest purchase yet, so it will be a while before you can Mapquest a route into or out of town using the exit.
The commission soon will have its maps available at its Web site, http://www.ccrpc.org.
The state transportation department has a wealth of maps online at http://www.dot.il.gov. But even those don't yet show the I-57 exit in southwest Champaign.
Spokeswoman Paris Ervin said the department updates its official printed highway map every two years, and its online maps annually.
The department gets its information from a variety of sources, according to Susan Stitt, chief of the planning services section. Transportation department workers throughout the state gather information, she said, and the department uses sources like the Champaign County mapping consortium.
Even individuals can help – "people who are interested in letting us know what's going on," including a letter carrier in the Chicago area, she said, adding the department confirms information from such sources before using it.
"It does take time for this to happen," she said, "as essential as these are."
They're essential in new ways, especially because of electronic maps, both online and in GPS devices, Stitt said.
"How else do you find where you're going when you're someplace new," she said, "or even when you're traveling locally in an area you're unfamiliar with?"
That happened to Moore.
"If you live here, you know how to get where you want to go," he said. "I've been here a little more than a year. I know Curtis Road now, but six months ago, I probably didn't know Curtis Road."
And Stitt said that because of the additional features of electronic maps, their accuracy becomes crucial, "not just for traveling at the holidays, although that's important, but for emergency services, trying to find the nearest hospital, the fire department."
The maps also become important for local economies, Stitt said.
"You can put in where's the closest place for coffee, where's the closest rest stop? They become more than a way to get somewhere. They're a destination information tool."