Game car prototype

Hi,

A client ask me about a prototype game car and i need some help to know if i can do it or not.
It's about a short game that the user can play for 1 or 2 min, not too long time it's just to demonstrate something, not to play a real game.

Imagine a car (and everything around) that commncate with a radar to:
-detect the best speed to don't stop on a red lights
-detect roadworks to alert user that they must change lanes
-detect firefighter car to go on the side
-detect other cars to prevent accident

I'm pretty sure it is possible with unity but i'm not very experienced with this tool.
I'm a experienced dev on iphone/android but i need someone to say me if it will be hard or not with unity3d.

Road are easy to make on unity but the road as to be a infinite road in a straight line, no turn, only the different situation that i have say above can appear randomly. Is this sort of infinite road easy to do ? how ?

Is a sort of radar that detect other object easy to do ? It should be something about distance i suppose.

For the car, i have already play a little with some assets like edy's vehicle and it's easy.
And the game has not to be realistic about speed or brake, a little of course but not that much.

On iphone/android i have the answer but with unity i'm really a beginner that's why any help are welcome.
It would be nice to know how many time(aproximately) it will take me to do this small game.

Graphics has not be really extra quality but not ugly too of course

All this exported to a flash format to not be limited on platform.
If you have only a part of the answer you are still very welcome.

Thanks