All those cars on California's famously gridlocked highways could be doing more than using energy. They could be producing it. The California Energy Commission is investing 2 million to study whether piezoelectric crystals can be used to produce electricity from the mechanical energy created by vehicles driving on roads. The commission is choosing a company or university to take on small-scale field tests. It will study how the small crystals, which generate energy when compressed, could produce electricity for the grid if installed under asphalt.

Elon Musk said SpaceX successfully tested its Raptor rocket engine that might one day be used to transport people to Mars. SpaceX "achieved first firing of the Raptor interplanetary transport engine," Musk said Sunday night on Twitter. The engine is powered by methane and liquid oxygen. The disclosure came on the eve of Musk's scheduled appearance Tuesday at the International Astronautical Congress in Guadalajara, Mexico, where he is expected to discuss SpaceX's efforts toward eventually reaching Mars. Musk is chief executive of Hawthorne-based SpaceX, a privately held company whose full name is Space Exploration Technologies Corp.

Suddenly the era of driverless cars seems very near indeed. Uber began testing driverless cars in Pittsburgh last week, and this week, the Obama administration endorsed the push to develop these vehicles. Adding to the momentum, Ford and BMW say they will produce autonomous cars by 2021. Driverless cars will create some big winners -- imagine how Uber's and Lyft's profits will jump when they can keep 100% of fares instead of letting drivers keep 70%. But they will produce some big losers too, notably the 5 million people nationwide -- including 600,000 in California -- who make their living driving taxis, buses, vans, trucks and e-hailing vehicles.

Sales of new homes retreated in August, one month after surging to the highest level in nearly nine years. Activity fell in all regions of the country except the West. New home sales dropped 7.6% last month to a seasonally adjusted annual rate of 609,000 units, the Commerce Department reported Monday. That followed a surge in sales in July, when they jumped 13.8% to a rate of 659,000, the fastest pace since October 2007. Sales had been expected to slow after the July surge.

U.S. stocks are slumping in Monday morning trading as healthcare companies and banks take the biggest losses. Energy companies are inching higher as oil prices rise. Major indexes in Europe and Asia are also starting the week on a steep skid. The Dow Jones industrial average was down 108 points, or 0.6%, to 18,153 as of 10:15 a.m. The Standard & Poor's 500 index fell 10 points, or 0.4%, to 2,155.

Nine people were shot and wounded, one critically, in a Houston neighborhood Monday morning by a lawyer who had issues with his law firm, authorities said. The first report of the shootings began at about 6:30 a.m. CDT, Police Chief Martha Montalvo said at a news conference, and when officers arrived, the suspect began firing at them. Police shot the man, whom Montalvo did not identify and who later died at the scene. Numerous weapons were found at the scene, Montalvo said, and a bomb-squad robot is looking at a Porsche that's believed to be the shooter's.

Elon Musk said SpaceX successfully tested its Raptor rocket engine that might one day be used to transport people to Mars. SpaceX "achieved first firing of the Raptor interplanetary transport engine," Musk said Sunday night on Twitter. The engine is powered by methane and liquid oxygen. The disclosure came on the eve of Musk's scheduled appearance Tuesday at the International Astronautical Congress in Guadalajara, Mexico, where he is expected to discuss SpaceX's efforts toward eventually reaching Mars. Musk is chief executive of Hawthorne-based SpaceX, a privately held company whose full name is Space Exploration Technologies Corp.