Cool-headed individuals in traffic control (5)
I believe the answer is:
cones
'cool-headed individuals in traffic control' is the definition.
I can't judge whether this definition defines the answer.
'cool-headed individuals' is the wordplay.
'cool' becomes 'co' (I can't justify this - if you can you should believe this answer much more).
'headed' means to remove the first letter (head can mean to remove the top from something).
'individuals' becomes 'ones' (one can mean an individual person or thing).
'ones' with its first letter removed is 'nes'.
'co'+'nes'='CONES'
Can you help me to learn more?
(Other definitions for cones that I've seen before include "(Volcano) peaks" , "Dry fruits of evergreen trees" , "Ice-cream holders or fruits of pine trees" , "subject of a former hotline" , "Shapes of wafers for ice-cream" .)