We were driving to South Padre Island from Laredo, Texas, on Friday around midnight. We were near Zapata when sudennly my uncle, who was driving about 65 miles/hr, got startled by an object with bright non flashing lights. He told my cousing who was sitting in the front seat about it. Then, I rushed to open the left window and looked out. To my amazement there was a round object moving west bound no higher than 2 to 3 stories over our head next to the road. I could not hear a sound. I couldn't see it take off it just disapeared out of my sight. My cousin who saw it first approaching our vehicle described it as a silver triangle. When I was able to see it more clearly, it was already overhead and it looked like a disk with a lot of lights underneath. I was trying to explain what was going on to my 11 year old daughter but I couldn't identify the object as any of the known aircrafts. The three of us who saw the object felt very confused and surprised as none of us could explain what we saw. When we got to the hotel we asked my cousins, who were driving in another suv in front of us, if they saw anything unusual but said that they didn't.