National Public Radio: General Motors and Segway unveiled a prototype two-wheeled electric vehicle that can seat two people. The Personal Urban Mobility and Accessibility, or PUMA, project is designed to be an alternative to cars and trucks in cities across the world. Critics have their doubts. The tech-review Web site Engadget calls it “a rickshaw without all the charm.” Another blog, Business Insider, dubs it “a hideous two-wheeled egg.” That’s some of the milder criticism of the new …