Beyond the MD 108 interchange, US 29 upgrades again into a fully limited-access six-lane grade-separated freeway as it encounters the western terminus of MD 100. The heavy flows to and from MD 100 result in US 29 widening again to eight lanes within the interchange, which also incorporates a three-quarter-diamond interchange with the western terminus of MD 103. The eight-lane segment narrows to six lanes again as it encounters the historic northern end of the US 29 expressway at U.S. Route 40 within Ellicott City.