David Castro, 18, back, runs after the solar car Helios 2, driven by Ricardo Sanchez, 17, during a test drive on Friday, July 11, 2014, at James Madison High School in San Antonio. Helios 2, built by the Madison Solar Car Initiative, a team of students at James Madison High School, will compete in this year's Solar Car Challenge, which begins July 18 in Fort Worth. Photo: Timothy Tai, San Antonio Express-News / © 2014 San Antonio Express-News