There IS a blue semi in Rio. I have beaten driver2 and found all four secret cars. The semi is one of the secret cars.
Go to take a ride, go to Rio, and pick any car you want. Look at the top of the map for a piece of the road that looks like the following:
____/'''''''\_____ Drive there and if you look hard, on the northern side of the road, there should be a switch.
Press the triangle button while right in front of the switch to open a gate by the building on the northern side of the road.
Once you get in the gate, if you drive along the barriers to your right, you should eventually come to the semi.
Trust me, this will not be a waste of your time. If the directions aren't specific enough, post a question.
If anyone needs help with the game, or finding the other secret cars just post something.
We have more cheats and tips for this game here, Driver 2 cheats
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