Metallic disc hovering over Rte. 3, 10 miles South of Boston, Ma on 09.15.16 at 18:45I was driving North on Rte. 3 in Hingham, MA, at 18:45 on Thursday, September 15, 2016, when I spotted a bright glowing light in the Northwest sky. I was not surprised and assumed this to be a plane as this is a normal air traffic route for incoming planes into Logan Airport in Boston. Where the sun was setting, I assumed it was just the reflection of the setting sun on an incoming airplane or a traffic helicopter. The object, however, then became clear and was disc like, and just appeared to hover over the highway while commercial airliners clearly were traveling around it in set patterns.The object was metallic in nature and appeared to glow and pulse in a bright white light. It hovered and move slowly from west to east in a very straight but smooth line, very different from a commercial jet. It also had no marker lights where all of the commercial jets around it blinked with red, green and white lights. It moved almost like a drone, smooth and deliberate, yet was much larger, solid metallic and disc shaped with a very distinct bright glow. The object moved East until it was over the ocean and then it just disappeared. In comparison to the full moon that was rising, it was about a quarter of the size.It appeared as though other cars may have noticed as traffic slowed and there were brake lights. Unfortunately, as I was driving, I was unable to get a photo. The whole ordeal lasted about 5-10 minutes.