Can I use a pin/password/pattern lock and safely have basic phone functionality while in car?

I would like to lock my phone with a pin for additional security. Also, I try to minimize my phone usage in the car, but in the event that I do need to call someone, I would like to be able to do so without having to enter a pin. I would like to do this by automated means if possible. I see two possible directions, but there could be others 1. Use some third-party lockscreen app that supports pin/password/pattern while containing shortcuts to a few apps. I've seen lockscreens that have shortcuts to certain apps, but they don't provide a pin lock. 2. Have a Car Home app that automatically launches when I plug in the headphones. Car Widget launches on headphone plugin, but it provides access to other screens as well, which I don't want. It has to be headphones though, I don't have a car dock or bluetooth or even a car power cable.