The user Laurent had an interesting reply to the question [Why hasn’t logic programming caught on?]:
If you look at the influence logic-programming has had in the field of -- air traffic control -- I don't think it can be said logic-programming has not caught on.
A question arises:
Where is prolog used for traffic control systems on the roads? Why is it used instead of languages, such as C or Python, in such environments?
This paper 'Commercial Applications of large Prolog Knowledge Bases' may be of interest. Another such read is (freely available as opposed to the former which requires Springer-Verlag membership) Finite State Grammatical Model and Parser for Air Traffic Controller's Commands.
I don't think it is being used in air traffic control - the post you quoted from gave no such references. And it is certainly not being used in road traffic control systems because there are no road traffic oontrol systems - do you call a controller before you make a left turn in your car?
Prolog is useful at implementing Expert Systems. So if you can think of an expert system useful in controlling traffic, you can use Prolog. I'm not an expert in traffic control and I'm sure it's a very interesting science(as I'm sure any driver sitting at a traffic light can tell you :D), but I think you can create such an expert system that can control traffic light times and synchronization based on statistical data collected over time, of cars passing through an intersection at different times of day.
I have no ideea of any such implemented systems, I'm just saying where I think Prolog might be useful to use.