Residential roads in Liverpool could be made into 20mph (32km/h) zones under proposals before the council.
The authority is exploring the idea of lowering 30mph restrictions after calls from road safety campaigners.
It follows the cabinet's backing of a motion put forward by Green Party councillor John Coyne last week.
However, the motion said the idea needs to be "properly explored and understood" before any decision can be made by the city council.
The proposal will be discussed at next week's regeneration and transport committee, and environment committee.
It calls on the chairs to agree a way of considering the "implications and practicalities of how it might be implemented".