City roads are to be painted with the new restriction – right next to the contrasting speed limit when leaving the zone on the other side of the carriageway.
It prompted a flurry of confused emoticons on social media as drivers came to terms with the new warnings.
But council bosses sought to reassure bemused drivers with a month’s notice before the new limits are enforced across vast swathes of the city.
“It looks quite fresh, I just think it’s hilarious,” a motorist tweeted about the new markings in Craigentinny Crescent.
Similar signs have been spotted at the Leith Walk end of London Road. Accompanying the painted warnings will be traditional speed limit signs at the side of the road.
The painted notifications of speed limits are part of a pioneering scheme to introduce 20mph limits across 80 per cent of Edinburgh’s roads.
The initiative was rolled out in the city centre and rural west of Edinburgh last August to a groundswell of initial opposition – with a 2700 signature petition to get the decision reversed.
But subsequent city-wide consultations reported positive feedback – amid some remaining concerns around increased congestion, road safety and longer journey times.
The first of its kind in Scotland, the scheme is expected to be fully rolled-out by next January – with £100 fines and three penalty points for drivers caught speeding. Key arterial routes – including Ferry Road, St John’s Road and Telford Road – are among the few that will retain 30 and 40mph limits.
Bosses at Lothian Buses have previously warned the new limits could lead to higher fares and poorer services.
AA spokesman Ian Crowder welcomed 20mph zones but only where “appropriate” – such as roads with schools.
He said: “Most collisions occur in these types of streets and there’s a significant difference between hitting someone at 20mph, when there’s a good chance they’ll survive, and 30mph where there’s a good chance they’ll be killed.”
But blanket 20mph zones across cities could be “counter-productive”, warns the motoring association.
“I would caution against putting 20mph limits across every street without good reason,” said Mr Crowder.
“Drivers can become irritated by it. The majority of people respect 30mph limits but 20mph is quite slow and people can start to ignore them.”
A council spokesperson explained the Craigentinny signs: “The 30mph road marking signifies the speed limit on Portobello Road on to which drivers exit.
“This will be reinforced by an adjacent road sign signalling the end of the 20mph zone, which will be erected before the 20mph limit comes into force in this area on February 28.
“The 20mph road marking refers to the 20mph speed limit on Craigentinny Crescent.”