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The purpose of the Phase 1 Regional Study Report was to better understand the existing conditions of the interchange and determine areas for improvement by reviewing the influence of regional and localized traffic generators, future traffic levels and travel patterns on the interchange area.
The report summarize the existing conditions as noted:
• 230,000 drivers use the interchange every day.
• With the exception of bridge surface maintenance, the bridges within the interchange area are in good condition.
• Most of the roadway pavement has experienced significant rehabilitation in recent years with pavement patching and overlays. Despite this rehabilitation, very little remaining service life is left in the pavement.
• Sections of the interchange area do not meet current design criteria. This includes several horizontal curves, ramp acceleration/deceleration lengths, weave distances and local service interchanges in close proximity to system
interchanges.
• Severe congestion levels exist in both the AM and PM peak hours on portions of the I-435, I-35 and K-10 corridors. Today, 20 percent of the interchange is congested. A drive through the interchange that should take 3 minutes actually takes, on average, 4 minutes due to congestion.
• The K-10 and I-435 highway crash rates are higher than the Kansas statewide average for similar facilities. The highest density of crashes occurs on I-435 from K-10 to Quivira. Rear end crashes are the most prevalent crash
type.
• Transit plays an important role in the interchange area. Johnson County Transit operates a number of fixed route
and flexible route (paratransit) services through the interchange.
• The SCOUT system is operated in part of the interchange area.
• Ramp metering service will be added in November 2009, to I-435 just east of the study area.

The report also summarize the future no-build conditions as:
• 360,000 drivers are expected to use the interchange by 2040.
• Regional historical growth patterns have shown a southerly and westerly development pattern along the I-35 and K-10 corridors. This growth pattern is expected to continue in the future. (As noted in chapter 3 of the report.)
• Regional traffic generators surround the study interchange and rely on the interchange area for access to the interstate system.
• Severe congested conditions are expected to occur in much of the AM and PM peak hours on portions of the
I-435, I-35 and K-10 corridors. By 2040, 50 percent of the interchange is expected to be congested. A typical
drive through the interchange that should take 3 minutes in uncongested conditions is expected to take 16
minutes at the peak hour by 2040.
• As traffic demand and congestion increase, the number of crashes is also expected to increase.

We’ve heard a number of comments about keeping through travelers in their lane, while those exiting should move to exit lanes. Like this comment, “make right hand lane from the K-10 Westbound exit in the I-435 Southound lanes a solid white line area (no passing to left 2 lanes). Dedicate this lane for only oncoming traffic or those exiting to I-35 Southbound. Make it this way until the Quivira exit. This would allow people in middle and left lanes to not have to stop on the interstate so people coming on could get in. Anyone wanting to go to I-35 would have to be in right hand lane from K-10 exit on to do so. This has worked for the Grandview triangle area, so it could work here. Would make it safer to get onto and off the highway since only oncoming and exiting cars would be using it. It is a short distance to stay in a dedicated lane. Would reduce possibility of being side swiped by impatient oncoming drivers and would help reduce rear end collisions caused by others stopping to let some rude driver in. It would also help on days when sun is in your eyse and you have problems seeing those wanting in and stopping traffic.”
Response:
As improvement options are developed the idea of keeping the ‘thru traveler’ in the appropriate lanes in order to keep traffic flowing has been discussed. Options for local traffic access would be separated in order to reduce conflict opportunities.