I drive from Lee's Summit / Blue Springs to Overland Park / Olathe during rush hour regularly. I used to make the commute daily.
I have driven in every major city in the country.
I am a transportation planner.
I consider myself an expert in comparing KC traffic to other cities

.
There is no traffic congestion in KC. Like I mentioned in this same thread in the Kansas forum, you will typically have a delay of 10-15 minutes tops. Many days, there will not even be a delay and on the worst days of the year, you might be delayed 20-30 minutes.
435 is a wide, urban beltway and when it slows down, it looks nasty.
But that's all it does is slow down, even at its worst, like when its slow from Nall or Metcalf all the way to 470, you are averaging 40-50 mph with a couple of points where you might have actual stop and go traffic. But the delay is minimal.
One of the biggest delays on the commute will be the ramp from EB I-470 to EB US-50. The far right lane of 470 is the only lane that takes you to 50 and it can get bad.
So, here is some good advise.
Don’t live on the US-50 corridor of Lee’s Summit. It’s not the best part of the city anyway, lots of track housing etc. It’s also flat, and ugly out that way with little trees or interesting topography. May as well live in Olathe.
Live south of 470 around Longview Farms, Longview Lake, or any of the areas along 3rd, or Longview Road. Very nice area with beautiful terrain and you can get off 470 at View High Drive rather than go to US-50.
You can even get to northern Lee’s Summit faster than having to go out along 50. Areas like Lakewood and around the big Legacy Park are also very upscale and the terrain is nice and hilly, forested and there are lots of lakes.
I would stay away from areas west of Raytown Road along 470. That’s KCMO and those are not too great of areas, some are downright ghettoish.
I would look seriously at the areas of Lee’s Summit that are within a mile of 470. Coming from Baltimore/DC, you will think you have died and gone to heaven when it comes to traffic times and how fast you can get around the metro.
We are looking at moving to DC due to a job and it’s just a totally different world here. People here don’t understand.
Do you have to or want to live in the suburbs?
KCMO has some great areas just east of state line that would put you minutes from the Kansas suburbs while giving you a more urban or charming area to live in. Again, another difference between KC and DC/Balt. You can live in a nice, safe part of the city not have to be a millionaire and you get can from the city to anyplace in JoCo in 15 minutes. A very nice home in Brookside will set you back 250-300k. That same home in DC would be at least 2 million plus a nasty commute TO the suburbs.