Glossary

EIS
Environmental Impact Statement. Federal law (the National Environmental Policy Act or NEPA) requires an EIS for all major transportation projects. The EIS generally describes the costs and benefits of different alternative courses of action. The EIS process for a section of freeway generally takes eighteen months to three years, but can take much longer; the EIS for I-69 between Evansville and Indianapolis will have taken about eight years when it is complete in late 2002. The EIS must be approved by the Environmental Protection Agency and Federal Highway Administration (FHWA) before any physical work (such as acquiring right-of-way or actual construction) can start on a section of road. For more details, see this page at FHWA or FHWA's NEPA website.
Freeway
A freeway is a limited-access highway where all intersections with other roads are built with a grade separations and through traffic on the highway does not have to stop for any reason (i.e. there are no railway crossings of traffic signals). Virtually all Interstate highways are freeways. Freeways are often called "expressways," "tollways," or "Interstates" (whether or not they actually are part of the Interstate highway system) in various parts of the country; however "freeway" is the preferred engineering term.
SIU
Section of Independent Utility. A section of a proposed highway that serves an independent purpose and would be useful without the remainder of the road being built. (For example, I-70 between Indianapolis and Columbus is an important highway, and the road link would be necessary even if the rest of I-70 had not been built.) The shortest possible SIU of a freeway is a section of roadway linked by two interchanges, but most are much longer; the 32 SIUs of I-69 (including 6 connecting spur routes) vary in length from 10 to around 200 miles.
“Super 2” Freeway
A highway with fully-controlled access (like a normal freeway) but with traffic in both directions sharing a single roadway. Some portions of the I-69 corridor, including part of the Southeast Arkansas I-69 Connector, will be initially built as “Super 2”s to save on initial construction costs.

State DOT Abbreviations on the I-69 Corridor:

See also: the misc.transport.road FAQ.

Back to I-69.

Chris Lawrence <i69@lordsutch.com> ( 1 Feb 2003 at 03:51 CST)