Outburst, as I get stuck in traffic (6)
I believe the answer is:
tirade
'outburst' is the definition.
(thesaurus)
'i get stuck in traffic' is the wordplay.
'get stuck in' indicates putting letters inside.
'traffic' becomes 'trade' (I've seen this before).
'i' placed inside 'trade' is 'TIRADE'.
'as' acts as a link.
(Other definitions for tirade that I've seen before include "Loud harangue" , "Sustained abuse" , "A prolonged outburst of abuse" , "Long, abusive speech" , "Blast of criticism" .)