A new bus service called Greenlink is now operating in downtown Houston, and rides are free of charge, according to DowntownHouston.org:
Through a partnership between the Downtown District, BG Group and Houston First Corporation, the downtown community can utilize the environmentally friendly buses to get them to popular downtown locations quickly.
Seven buses operate Monday through Friday, 6:30 am to 6:30 pm, every 7-10 minutes. The route spans 2.5 miles with 18 stops and connects major office buildings along Smith and Louisiana streets to METRO transit, the convention corridor, hotels, restaurants, shopping and entertainment. Popular downtown destinations along the route include the George R. Brown Convention Center, Main Street Square, Discovery Green, Macy’s, Houston Pavilions, City Hall and the Central Library.
The buses run on Compressed Natural Gas (CNG), making them a cleaner transportation alternative. Features of the buses include a streamlined, modern design, low-floor access, perimeter seating, high-quality air conditioning, 28-seat capacity and are ADA compliant. The buses will be manufactured by Gillig LLC in the USA.
See the map here.