Cameras tucked into orange barrels videotaped the license plates of thousands of drivers on Interstate 35 as part of a Texas Department of Transportation study of the busy highway, officials said. The 21 camera points scattered along the I-35 corridor between Dallas and Mexico included two in Central Texas, one north of Round Rock and the other in Kyle. The cameras caught both north- and southbound cars, agency spokeswoman Gaby Garcia said. Critics of last month's study questioned whether it invaded motorists' privacy. But Garcia said the study and others planned for the future are vital to transportation planning and...