Hmmm....
Actually, my understanding is that the new law makes it illegal for businesses to prevent employees from keeping firearms/handguns in their vehicles at work. This is a big distinction, since there were/are businesses that already allow this. You always could legally have a gun in your vehicle, however your place of employment may have had a policy against it. So now its not a matter of you are no longer breaking the law (you never were in the first place), but that said place of employment would now be breaking the law if they retained a policy preventing you from doing so [keeping a handgun in your vehicle].