You can use the word "optimistic" for people and situations but I'd word it differently. I'd say something like, The transportation demand 'outweighs' the transportation capacity which at present, doesn't give one much optimism (for.........) You can't say it, "makes the situation not optimistic". That's like saying something has been created and then not - you'd have to say something like the situation didn't give people much optimism - optimism is the hope of positive things. You can't give someone or something none hope of positive things. "I'm optimistic about the situation" "I will keep my optimism - I'll hope for the best result" "The situation is grave" "the demand outweighs (using imaginary weight to illustrate) the ability to supply, so it's not looking very optimistic" or "the situation is bleak" "the situation isn't very tenable" "the demand outweighs the ability to supply which will lead to a lack of optimism towards the corporations success". Get it? If you flipped it over - you could say, "The transportation demand doesn't outweigh the transportation capacity, which gives investors and the general public some optimism for continued success and profit" The problem with your paragraph is that you said it makes the situation, "not" something - you have to say what the situation is - the situation is poor the situation is grave the situation is non tenable the situation is encouraging the situation is overwhelming etc you'd never say the situation is not poor the situation is not encouraging (it would be discouraging) I hope this helps you X Craig

My preference would be to use "optimal" (most desired outcome) for a situation and "optimistic" (expecting the best outcome) for a person or something related to a person. For your sentence "The transportation demand outclasses the transportation capacity, which makes the situation not optimistic," I would probably rewrite it as "The transportation demand EXCEEDS the transportation capacity, which makes the situation LESS THAN IDEAL." "Ideal" refers to your goal, which is that people can get to where they need to go without waiting too long.

Optimistic can be used to describe both a situation or a person. To describe a person, you could say: "He/she is really optimistic." or "He/she has an optimistic outlook."

Yes, I've come across such a collocation.