This is from the Science Frontiers web site by William Corliss: (http://www.science-frontiers.com/sf083/sf083g11.htm)

Some members of the Houston Association for Scientific Thinking (HAST) have visited the sites of the famed Marfa Lights (West Texas) and the less-publicized Saratoga Lights (East Texas). With binoculars, telescopes, and road maps, it was fairly easy for them to ascertain that the Saratoga Lights were simply the headlights of automobiles traveling along Route 787. The Saratoga display is a bit eerie but not at all mysterious, according to HAST. Admitting that the Marfa Lights are indeed entrancing and even mildly mystical, the report closes (rather incongruously for an admittedly skeptical writer) with: "A reminder that caution must be taken. Because what we saw four nights in Saratoga and three nights in Marfa did not go out of the bounds of the ordinary does not mean that the extraordinary has never occurred in either place." (Lindee, Herbert; "Ghost Lights of Texas," Skeptical Inquirer, 16:400, 1992.) Comment. Previous descriptions of the Marfa lights in Science Frontiers (#34 and #51) seem to portray phenomena much more "extraordinary" than automobile headlights! In SF#34, for example, one of the "lights" is said to have approached to within a few feet of a car and then followed it for a couple miles. Reference. For a comprehensive treatment of "nocturnal lights," refer to Chapter GLN in our catalog: Lightning, Auroras, Nocturnal, Lights. Ordering information here. From Science Frontiers #83, SEP-OCT 1992. (c) 1992-2000 William R. Corliss

The lights were variously rationalized as the reflections of car lights going in to Saratoga, patches of low-grade gas, a reflection of foxfire or swamp fire, or the figment of hysterical imaginations. (From the Handbook of Texas web site (http://www.tsha.utexas.edu/handbook/online/articles/view/BB/lxb1.html): BIG THICKET LIGHT.)