Texas passed changes that wente into effect 9/2005 allowing an individual to carry a pistol in his/her car without risk of arrest (conditions do apply). See the link below:
http://www.gunlaws.com/tgogup3.htm
Part of the description of changes that pertain to your questions are:
The definition of "traveling," for the exemption from a charge of illegal carry under 46.15(b)(3), is this:
A person is presumed to be traveling if the person is:
(1) in a private motor vehicle;
(2) not otherwise engaged in criminal activity, other than a Class C misdemeanor that is a violation of a law or ordinance regulating traffic;
(3) not otherwise prohibited by law from possessing a firearm;
(4) not a member of a criminal street gang, as defined by Section 71.01; and
(5) not carrying a handgun in plain view.
Check the link out. Hope this helps. JD