I don’t believe there is any way of getting the answers on a plate. i think you will need to do the geometry and network operations yourself.
Also, how do you define distance? What constitutes a Major Road? What constitutes a Highway?
I don’ t really understand the “in a buffer with size x” bit.
I’d guess you will be happy with plane geometry approximations, and using the centre line of the road, in which case the geometry should be easy. However, it might not be terribly useful if there are obstructions in the way.
I’m currently working with Land Use model in order to define a pollution model given many different data.
The distance is intended in line of view and the buffer is simply the radius given a point of interest.