In the capital of the United Arab Emirates (UAE), Abu Dhabi, there is confusion on the roads after the local council replaced green traffic lights with blue ones.
The mix-up came after Abu Dhabi municipality received blue, rather than green, lenses from Germany.
Red for stop, amber for anticipation and green - no, apparently it is blue for go.
That is the perplexing sequence of traffic signals drivers in Abu Dhabi are facing.
Many are confused as to whether to remain stationary at junctions or move off as normal.
Several busy city-centre streets are affected.
Engineers and technicians are working to correct the situation but there is speculation that could take some time because of the wait for replacement green parts.
Accident fears
The change of lenses is part of an overhaul of the capital's road system and the move towards new LED (light-emitting diode) technology.
Police are reported to be concerned that the resulting confusion could lead to accidents.
The blue lights do not conform to internationally recognised traffic signals.
Certainly the tooting common in the UAE from cars waiting in line for the front driver to move off seems destined to get louder.
However, a source at Abu Dhabi municipality says he has received some comments appreciating the blue lights.
He says some people appear glad of the change.
Nevertheless, the mix-up does call into question the much-used phrase "being given the green light".