I’ve noticed that ZipCar or whatever they have in the DC area also is renting out pickup trucks. I think I might look into that option the next time I need to rent a truck.
You need to apply for a ZipCar membership first. I think it's a $25 application fee and $50/year. It's not instant enrollment, so you must do it about 2 weeks before you plan to rent the truck.
I'm not sure why they think they need to "test" this in Austin. ZipCar has been renting cars using this methodology for quite a while, and it worked well for me.