Road planners embrace the diverging diamond interchange

Overall reception

• Many commenters report local diverging diamond interchanges (DDIs) and say they work noticeably better for vehicle throughput than previous designs.
• Others find them confusing, especially when rarely used or poorly marked, though several note that when well executed they feel like “just normal intersections of one‑way roads.”
• A minority say their local DDI is “awful,” with long waits at lights, and prefer cloverleafs where land allows.

Versus roundabouts

• Strong debate: some argue a roundabout in similar space would be simpler, signal‑free, forgiving of mistakes, and more self‑explanatory.
• Others counter that roundabouts struggle with multi‑lane high‑volume flows, especially heavy turning movements, and can “lock up” under dominant flows (e.g., big rush‑hour left turns).
• Several note that multi‑lane or signalized roundabouts can become complex and unpleasant, especially for cyclists.

Versus cloverleafs and stacks

• DDIs are described as a compromise where a full cloverleaf or stack is too land‑ or cost‑intensive.
• Compared to cloverleafs, DDIs reduce conflict points and ramp weaving but usually require signals.
• Stack interchanges would remove crossovers entirely but are labeled larger, more expensive, and less pedestrian/bike friendly.

Pedestrians and cyclists

• Some say DDIs are worse for pedestrians due to multiple crossings and being surrounded by high‑speed traffic and noise.
• Others argue they can be safer: shorter, signalized crossings, traffic from only one direction, and no unprotected turning conflicts.
• Several note that such interchanges are inherently hostile to pedestrians regardless of type; where present, bike/ped underpasses or side paths can mitigate this.

Safety, learning curve, and design execution

• Reported crash reductions are mentioned, but some suggest any new design temporarily improves safety because drivers pay more attention.
• Good implementations emphasize strong lane markings, clear advance signage, pronounced curvature, and high barriers to minimize “wrong‑side” panic.
• Poor paint, complex overlays, or asymmetric control (e.g., odd stop signs) are blamed for wrong‑way incidents and confusion.

Land use and urban planning

• Some call DDIs a “colossal waste of land” reinforcing car‑centric design and CO₂ emissions; others defend cars as highly useful and argue it’s unwise to compromise vehicle design for symbolic reasons.