Study Approach

The Council Bluffs Interstate System (CBIS) improvements project is being conducted in two tiers.

Tier 1 focused on the entire interstate system to identify the needs of the system and develop possible solutions (alternatives) to meet those needs. An Environmental Impact Statement (EIS) was prepared to document the system study. Due to the magnitude of the improvements, at the end of Tier 1 the interstate system was divided into segments for further study in Tier 2, as shown below. Click here for more information on Tier 1.

Tier 2 is focused on detailed engineering and environmental studies for each segment of the interstate system. During Tier 2 specific details about project design and property impacts will be determined, additional environmental documentation will be prepared and construction plans will be finalized. There will be additional opportunities for public input throughout Tier 2.