There will need to be a high level of confidence that, if and where the limit is raised back to 30mph, it will not result in the very risks the policy was designed to mitigate.
Bydd angen lefel uchel o hyder, os a lle codir y terfyn yn ôl i 30mya, na fydd yn arwain at yr union risgiau y cafodd y polisi eu llunio i liniaru.