20mph: Wales speed limit sat-nav warning ahead of change

Wales will become the first UK nation to adopt 20mph ( 32km/h ) in built-up areas.

RAC warns drivers not to rely on sat-navs for speed limit on residential roads.

Police in Wales say enforcement will be a "last resort" as drivers adjust to the change.

Not all 30mph roads - about 3% across Wales - are reducing their speed limit.

Local authorities can and have made exemptions to put limit back to 30mph .

Councils told by the Welsh government that exemptions can be made where "strong evidence exists that higher speeds are safe" A petition against the 20mph limit was debated in the Welsh Parliament .