Temporary traffic lights on St Helen's Street in Derby
Drivers in Derby have seen increasing numbers of temporary traffic lights on the city's roads as the Connecting Derby project continues apace.
Most of them work fine but what should you do if faced with a set - or even a permanent set of signals - that have become stuck on red?
It's a problem that has been encountered by drivers on Friar Gate and St Helen's Street in recent weeks.
And there are a few things to bear in mind if you're in that situation.
Derbyshire Police and the Institute of Advanced Motorists say first of all you should give the lights plenty of chance to change from red to amber.
"It's a tricky one because the absolute copper-bottom rule is that the red light must be obeyed", says Vince Yearly from the Institute of Advanced Motorists.
"However, if you've been sitting there for a few minutes and it's become fairly obvious the lights aren't changing then you've got to reconsider.
"So if you can see ahead of you quite clearly and can ideally see the other set of lights or the back of them, I would lower my window a little to hear if there's anything moving in your vicinity.
"Then put your lights on and very tentatively and cautiously start to make your way forward.
"It's not a very scientific answer and it needs a liberal dose of common sense but at the first hint you've miscalculated and the lights have just been on a long red, you should reconsider and reposition the vehicle."
Derbyshire Police echoed this advice adding that drivers should wait at least four minutes before opting to move forward.
Drivers are also urged to report the problem to the authorities at the first opportunity.