It specifically legalizes lane-splitting. SB 506:
Here's the text in PDF format. The underlined portion is new:
If you don't know who your Texas state senator is, go to this page, type your address and zip code in the space provided, and it'll tell you the name with a link to his or her official web site. Once at the web site you can submit a message.
The author of the bill is Sen. John Carona from Dallas County (LINK to his official website). He is the Chairman of the Senate Committee on Transportation & Homeland Security.