Glimpsing a greener future: Computer model foresees effects of alternative transportation fuels

It’s the year 2060, and 75 percent of drivers in the Greater Los Angeles area have hydrogen fuel cell vehicles that emit only water vapor. Look into Shane Stephens-Romero’s crystal ball — a computer model called STREET — and find that air quality has significantly improved. Greenhouse gas emissions are more than 60 percent lower than in 2009, and levels of microscopic soot and ozone are about 15 percent and 10 percent lower, respectively.