With Metro still tackling safety and operational issues, and toll rates occasionally hitting $40 or more on the Interstate 66 express lanes inside the Capital Beltway, tolerable options for commuters in Northern Virginia seem hard to come by these days. Kalai Kandasamy wants to offer an alternative. The cybersecurity and information technology consultant developed a Sluglines app in 2016 that helps prospective riders and drivers coordinate trips, and he believes that establishing slug lines in the I-66 corridor could alleviate travel headaches for some workers. “Slugging fills up those empty seats, and it’s good for the environment,” Kandasamy said. “It’s...