What are the main types of at-grade intersections?

At-grade intersection types include: T-intersection (three-leg), four-way intersection, multi-leg intersection (5+ approaches), and roundabout (circular). Configuration options: channelized (raised islands guide traffic), unchannelized (painted markings), and signalized or unsignalized control. Selection depends on traffic volumes, turning movements, safety requirements, available space, and traffic control. Roundabouts reduce conflict points and severity of crashes compared to conventional intersections.