Being able to keep your gun in your car at work would presumably have a big impact on carrying rates

I haven't checked the Brady Campaign info that was published in the WSJ here.  But that is largely beside the point here.  My guess is that the rate that people carry their concealed handguns with them will vary a lot depending on whether they can keep their guns locked in their cars at work.  If you can't have your gun locked in your car, you won't have your gun with you on anyplace that you go to or from work.  It would thus be expected to make a difference in the impact that concealed carry has on crime rates across the states.  The WSJ article gives one take on the debate to pass these laws.

Thanks to Nikki for sending me this link.