Final answer:
A stairway with four or more risers is required to have a handrail on at least one side for safety, guidance, and accessibility purposes, according to common building codes and safety standards.
Step-by-step explanation:
Any stairway of four or more risers should have a handrail on at least one side. This is a safety measure to ensure that individuals have something to hold onto during their ascent or descent, which helps in preventing falls and injuries. Moreover, the handrail serves as a guide for those with visual impairments, contributing to the overall accessibility of the staircase.
Local building codes typically specify the minimum requirements for staircase safety features, including the height and placement of handrails. In some contexts, such as in public buildings or where more stringent safety standards are upheld, handrails might be required on both sides of the stairway.