Long waits and overcrowding in hospital emergency departments (EDs) increase patient risk. To reduce risk, a new patient flow process titled “Door-to-Doc” (D2D) was developed. D2D improves patient safety and reduces left without treatment (LWOT) rates by reducing the time patients wait to see an ED physician. To do this, D2D includes implementation of “people” and “process” tools through large-scale organizational collaboration and the use of queuing theory. This chapter describes the creation, execution, validation, and results of the D2D process and D2D Toolkit in eight diverse Banner Health EDs. Results include LWOT reduction between 35 percent and 65 percent. Last, this chapter describes the D2D Toolkit that is publically available for implementation in any ED.