"Was there a lot of traffic?"
Translation:Gab es viel Verkehr?
Most commonly, you will see the translations viel = "much/a lot of" for uncountable things and viele = "many" for countable things.
What I mean by this is that you can't count traffic (Verkehr): "How many traffics were there?" is nonsense. So here, viel fits.
If you rephrase to use a countable noun, like "traffic jams" (Staus), then you would use viele.
Gab es viel (Verkehr)? = "Was there much (traffic)?"
Gab es viele (Staus)? = "Were there many (traffic jams)?"
I think it's probably the difference in meaning. Gab es is kind of like asking "did the ... exist?". In another context, say "Was he at the party?", where we aren't talking about existence, but the presence, then "War er bei der Party?" seems ok to me.
Aside from that, you can report it. My experience here in Germany is that the "gibt/gab es" form is used in this context.