Dozens of engineers, environmental scientists, experts in noise, water, wildlife and a bevy of social sciences studied the defined area depicted on the study area map in a process that began in 1993.

Their work produced the Environmental Impact Statement (EIS) that was the basis for the Record of Decision. In the end, the EIS recommended 3D1 MOD-3 after systematically eliminating all other potential alignments as being either unworkable or too damaging to the environment.

Initially, more than 15 potential paths for the bypass and a no-build alternative were investigated during the preliminary stages of the project's development. The number was narrowed to four workable alternatives and a no-build. Each was presented in detail in the Draft Environmental Impact Statement (DEIS) issued in late 1995. Following a public hearing on the DEIS, two additional alignments were added to the mix and studied.

A Supplimental Draft Environmental Impact Statement (SDEIS) was issued and circulated in early 1998.

Then in late 1999, two species of fish - the bridle shiner and the ironcolor shiner - found in the Marshalls Creek were added to the list of endangered species. The study team was required to find yet another path for the roadway, one that would avoid the Creek as much as possible.

Final adjustments were made to the proposed alignment generally known as 3D1. This third modification of that path was 3D1 MOD3.