Are the BIP 100, BIP 101 and BIP 102 proposals being voted on now by miners? What is the procedure for a bitcoin miner to vote for a particular BIP and where can a tally of votes be viewed?
Rather, the BIP is accepted or rejected on the basis of consensus. Consensus is never defined, but even if you interpret it fairly broadly, I don't think any of the three will reach consensus.
There are frequently blockchain votes about activating the new rules, but that's less of a mechanism to measure acceptance and more of a way to only deploy the new changes once enough of the network runs them that the switchover won't be disruptive.
There is a related issue, which is Bitcoin-XT, which grew out of several developer's frustrations with the process. That proposes to alter the blocksize according to BIP 101 once more than 75% of the blocks are created by Bitcoin-XT nodes. But that's not something within the BIP process.