What feature is used to clearly mark side escape hatches?

The correct answer identifies yellow decals as the feature used to clearly mark side escape hatches. This choice aligns with standard safety protocols in aviation, where color-coding is employed to increase visibility and facilitate quick identification of critical areas, such as escape routes. Yellow is often associated with caution and is easily recognizable, which is vital in emergency situations where time is of the essence.

Other options such as red stripes, green lights, and blue markers may serve distinct purposes in aviation, but they do not specifically denote escape hatches. Red is typically used for danger or alerts, while green lights can often indicate safe conditions or the go-ahead for processes. Blue markers are less commonly used in aviation safety protocols and are not standardized for marking escape routes. Thus, the use of yellow decals serves an important role in contributing to the overall safety and efficiency of escape procedures.