'Control cities' designated for interstate signs

Q. Sometimes I read a sign on the road informing drivers the highway goes to Tennessee when all I really want to know is will it take me to the South suburbs.

Why can't those signs say, "South suburbs-Kankakee-Champaign-and eventually Memphis" or "Western suburbs-Aurora-DeKalb-and in a few hours Iowa?"

--J. B., Lisle

A. Jan Kemp, assistant press secretary with the Illinois Toll Highway Authority, said larger cities across the country became designated as "destination cities" for the purpose of providing motorist information on interstate guide signs when construction of the interstate system began back in 1956.

"Typically, the next major city or state is identified on the overhead signs," Kemp said.

"Memphis is commonly the destination city on the guide signs on I-57 going southbound because it's the next major city you encounter."

According to Kemp, Aurora is considered a destination city within Illinois because, as one moves out of Chicago, it's one of the largest cities outside of Chicago.

"Long-distance travelers may not know where local towns are, but they do know the names of larger cities," Kemp said.

Dan Hecox, spokesman for the Federal Highway Administration in Washington, D.C., says Aurora was selected as a destination city for another reason.

"Major destinations or 'control cities' shown on the interstate guide signs were a state responsibility -- not a federal one -- and were determined by each state," Hecox said.

The American Association of State Highway and Transportation Officials maintains and publishes "The List of Control Cities for Use in Guide Signs on Interstate Highways."

"From time to time, states may recognize the need to add a city to the list of control cities for an interstate route within its boundaries, and can submit a request to the AASHTO," Hecox said.

Some local interstate signs do direct drivers in a more general way.

For instance, I-355 north takes drivers to the "Northwest Suburbs," and I-290 west from downtown Chicago takes drivers to the "Western Suburbs."