Actually captcha these days is nearly full proof. Bots can't select street lights or click on buses in the captcha photos. The captcha of 2005 was easy to defeat which was just a simple 4-6 letter captcha but these days it's full proof.
If you're on a "clean" IP address, you can also use the audio captcha solver
buster, which is a browser extension that feeds the audio challenge back into Google's own speech recognition software. Captcha has gotten more advanced, but so have the tools used to solve them. It's an endless arms race.