The earliest known recorded form of 走 is it's Bronze script. 走 is an interesting radical because it's Seal form was already a compound ideogram. In its Seal form, you can clearly see a person running over the character for foot, 止. This is a clear depiction of the original concept for 走, "to run on foot".
Today, 走 is rarely used to mean "Run", instead it is most often used to mean "To Go" and "Walk".
When 走 is used as a radical, it can be found in over 20 words such as: 赶 (hurry up)，起 (stand up)，and 超 (bypass).