Previous analysis concluded that all segments of SR 400 between I-285 and Holcomb Bridge Road operated at Level of Service (LOS) E or LOS F in the peak-period/peak-direction in 2010. Level of Service is a measure of traffic congestion ranging from A (free flow) to F (forced or breakdown flow). The 2012 feasibility study showed that this trend continues, with traffic forecasts predicting that all segments of SR 400 within the project limits described above would operate at LOS E or LOS F in the peak-period/peak-direction in 2040. Additionally, the analysis showed that under 2010 conditions, traversing the project limits in the peak-period/peak-direction requires 25 to 35 minutes of additional travel time as compared to traversing the project limits at posted speeds. Similarly, in 2040, the gap between posted speed travel time and actual peak-period/peak-direction travel time grows to range from 55 to 90 minutes.
Based on these existing conditions a need was identified to improve mobility along the corridor.