Both are correct but have different meanings: 1. A lot is not negative. It just means there is a large amount 2. Too much means there is a large amount and it is causing a problem ... in this case it will delay your journey Take a peak at my resources on the subject: http://askpaulenglish.blogspot.co.uk/2017/05/too-muchmany.html

Both make sense. It depends on what you are trying to say. "too much" indicates that you cannot cope with the amount of traffic. So in this case if you were driving you might turn around, or find another way to get to your destination. "a lot of traffic" is just an observation, you've noticed that a road is busier than normal. If you were driving you would just deal with the amount of traffic

I think the first one is a better statement, "there is a lot of traffic here". But it sounds better without 'here'. If you were more annoyed with the traffic then you would say "there is too much traffic here" I would say this sentence though "There is so much traffic here!" or "there's a lot of traffic".