Since parking, stop — perhaps on this (7)
I believe the answer is:
asphalt
'on this' is the definition.
The definition suggests a singular noun which matches the answer.
'since parking stop' is the wordplay.
'since' becomes 'as' (both can mean 'because').
'parking' becomes 'p' (abbreviation on road signs).
'stop' becomes 'halt' (halt can mean to stop).
'as'+'p'+'halt'='ASPHALT'
'perhaps' is the link.
Can you help me to learn more?
(Other definitions for asphalt that I've seen before include "What you see on roads" , "Substance used in roofing and paving" , "Road-surfacing material" , "Bituminous road dressing" , "Material for road surfacing etc" .)