smoking on buses?

I am considering traveling by bus in Spain this summer and was curious about smoking policy. Do all buses allow smoking, are there ever nonsmoking sections/buses? Thanks!!!

All the buses I've been on recently (all in Andalucia)have been completely no smoking. It used to be you could smoke at the back, but they stopped it a few years back.

As Eddie said - no smoking on the buses - trains have smoking areas - either cars or in the bar area