You can sue, but you'll loose 100% for sure if it states in the terms and conditions that they are not responsible for what you do while using the app and they put a disclaimer telling you to drive safely, watch where you're going be aware of your surroundings etc.
Depending on the judge, the case might just be thrown out altogether. It's really open and shut.
A release of liability form will only keep the company from harm if they are not endangering their consumers in any unreasonable way. It's legally nothing--a reminder at best that they can bring up to say "Hey, we warned them not to do X and they said they wouldn't sue us if they did."
Companies do not set their own terms of liability. A company cannot abduct you and steal your organs because you checked "Agree" on a 45 page mstar fishcript of terms and conditions. They are not legally bijnding.
Unless you actually negotiate a paid contract--like with a stunt actor, the court will only take your liability warning into consideration.
So as I said before:
If Pokemon Go put extra rare ghost Pokemon on toxic radiation landfills and sent users to collect them, it wouldn't matter how many disclaimers you sign without reading, you could sue them for putting the consumer in harm's way.
Obviously I would never encourage such a frivolous lawsuit, but let's not sit here and act like it's impossible in any way.
I don't think the lawsuit would get anywhere, but that is because Pokemon Go does not endanger users beyond sending them out walking, which many people would do anyway.