When the current K-10 expressway was originally completed between K-7 and I-435, it was originally signed as K-12. When the entire expressway was completed from Lawrence to I-435 in Lenexa, K-10 was signed for the entire freeway, and K-12 was realigned to follow the old K-10 routing on Shawnee Mission Parkway to Merriam Drive. The former Spur K-10 was then resigned as Spur K-12.
The K-10 expressway initially ran between K-7 and I-435, but was later expanded to encompass the entire route from Lawrence to I-435 in Lenexa. This led to a change in signage, with K-10 being used for the entire freeway, while K-12 was realigned along the old K-10 route on Shawnee Mission Parkway and Merriam Drive.