Whereat parking causes mere chaos around a road junction? (5)
I believe the answer is:
meter
'whereat parking causes' is the definition.
I can't judge whether this definition defines the answer.
'mere chaos around a road junction?' is the wordplay.
'chaos' indicates an anagram.
'around' is an insertion indicator.
'a road junction?' becomes 'T' (T-junction is a type of road junction).
'mere' anagrammed gives 'meer'.
'meer' going around 't' is 'METER'.
Can you help me to learn more?
(Other definitions for meter that I've seen before include "Device that measures, say, electricity usage" , "Something measuring" , "Device to measure quantity used of fluid, electricity etc" , "Poe sometimes used this" , "Device for recording, say, usage (5)" .)