"Guardrails" built by the EU to govern AI fall short in both ambition and execution and have become too heavy to absorb rapid changes in technology, a new study in Big Data & Society warns.

The rules took years of negotiations and political effort and are difficult to change but not to remove, making them a "rigidity trap in action."

Recent changes have amounted to a "partial retreat" before the EU AI Act has been fully implemented, experts have said. The European Union's 2024 AI Act, supposed to take effect this year, has already been replaced with the 2026 AI Simplification Act.

The study says the EU's regulatory framework fails to fulfill the European Commission's stated goals of promoting trustworthy, human-centric and rights-respecting AI.

In contrast, in the U.S.—more by accident than design—there are "regulatory leashes" that can be pulled in response to need, and these are more binding and enforceable than the EU guardrails. Rules are more concrete and easier to enforce.

The study, by Alison Harcourt of the University of Exeter, Claudio M. Radaelli of the European University Institute and Philipp Trein of the University of Lausanne, says the EU's efforts to anticipate AI risks and impose comprehensive rules made adaptive regulation hard to develop. This has made the AI Act hard to enforce and limited its capacity to protect human rights and public values.

The United States intervenes legislatively when specific risks are clearly present or on a sector-by-sector basis. The study says this approach is more enforceable than the EU AI Act, and the state-by-state and sector-by-sector evolution of rules provides more space for learning from experience.