Correspondence of tenses
 

The other day I said to my friend who speaks decent Engish but is a native spanish speaker, "Pensé que habría habido más tráfico," (I thought there would have been more traffic) and he corrected me and said that construction isn't possible in Spanish, and that I should say instead, "Pensé que iba a haber más tráfico." This led me to review coordination of tense possibilities.

I have a chart of coordination of tenses/moods, but I realized that the following types of constructions are not on there; nor are they listed as prohibited.

Would anyone please tell me if the following sentences are valid in Spanish?

1) No había comido nada porque pensé que ella me daría algo de comer.
(I hadn't eaten anything because I thought that she would give me something to eat.)

2) Ya había comido porque no pensaba que ella me diera algo de comer.
(I had already eaten because I didn't think that she woud give me something to eat.)

3) Ya había comido porque no pensaba que ella me fuera a dar algo de comer.
(I had already eaten because I didn't think that she was going to give me something to eat.)

4) No había comido porque pensé que ella me habría preparado algo de comer.
(I hadn't eaten because I thought that she would have prepared me something to eat.)

5) Ya había comido porque no pensaba que me hubiera preparado nada de comer.
(I had already eaten because I didn't think that she would have prepared something to eat.)

Thanks in advance!

Not 100% sure about the scope of the English expressions, but all five Spanish phrases are OK.

Number 2 can be also "me daría" and "me iba a dar", it depends you are focused in the moment you "though" that or it's a retrospective, and if you are dealing with that as a new piece of information or as a known piece of information, besides other possible shades and nuances.

Thanks! Just a quick follow-up question-

If #4 is ok, then why wasn't my original statement to my friend, "Pensé que habría habido más tráfico," ("I thought that there would have been more traffic.") not OK? Is it just not how a native speaker would say it and actually is gramatically correct?

I concur with what your friend told you as I have problems to wrap my mind around both your English and Spanish original phrases because of the perfective aspect (something finished at the time of speaking), the perfect compound tense (something that was over prior to the time in the sentence) and the potential mood (or aspect) which refers to a hypothetical "reality" -what you expected, as opposed to what was real-. It sort of looks like oil and vinegar to me.

In your example #4 you are combining two statements: You haven't eaten yet and you have thought she would prepare something for you to eat. The second one is the cause of the first one, so, you haven't eaten yet because you have thought she would prepare some food. Then you report that as a past circumstance: You hadn't eaten yet because you thought she would have prepared some food.

In your original example there is just one statement: what you thought, which includes your notion about how the traffic would be, so there's just one temporalidad (time stamp?) so there's no place to the perfect compound tense in Spanish. If you "pensaste" something, you "no piensas" that something any more, and the thing you "pensaste" ended up being not real, but it was potential as all your expectations were that to be such way, so conditional-potential is required "pensé que a esta hora habría más tránsito" in the present, and turned into the past "había pensado (or pensaba) que a esa hora habría habido más tránsito". Remember that in the present you no longer "piensas" what you are commenting about, so it's "pensé". If you want to speak of the past, you use "pensaba", as imperfect doesn't care about the connection of those facts and the present. This is sort of a word salad, but in your example you should think of "pensé..." as "ahora no pienso más lo que pensaba antes", so your "pensé que habría habido más tráfico" means to us something like "I no longer think there would have been more traffic".

Excellent explanation as always!
Thanks!!!

You're welcome! :)