A placa dizia que havia pedágio na frente e também avisava sobre engarrafamento.

The sign said there was a toll up ahead and also warned about a traffic jam.

Breakdown of A placa dizia que havia pedágio na frente e também avisava sobre engarrafamento.

• e: and
• sobre: about
• também: also
• que: that

Questions & Answers about A placa dizia que havia pedágio na frente e também avisava sobre engarrafamento.

Why is it dizia and avisava instead of disse and avisou?

Because dizia and avisava are in the imperfect past. In this sentence, that gives the idea of what the sign said / was saying and was warning about as a general statement, not as one single completed action.

With signs, notices, and written text, Portuguese often uses the imperfect this way:

• A placa dizia... = The sign said...
• O bilhete dizia... = The note said...

Using disse or avisou would sound more like a specific completed event:

• A placa disse... is grammatically possible, but much less natural here.

So dizia and avisava fit the idea of ongoing written information on a sign.

Why does the sentence use havia? What does it mean here?