MD 146 from the center of Towson to the Baltimore Beltway was expanded to a divided highway concurrent with the construction of the highway's cloverleaf interchange with the Beltway between 1955 and 1958. The portions of Dulaney Valley Road and Jarrettsville Pike through the Loch Raven Reservoir reservation were originally maintained by the Baltimore City Department of Transportation since the reservoir is owned by the city of Baltimore.
MD 146, a highway connecting Towson to the Baltimore Beltway, was upgraded into a divided road during its construction between 1955 and 1958. The sections of Dulaney Valley Road and Jarrettsville Pike within the Loch Raven Reservoir reservation were initially overseen by the Baltimore City Department of Transportation due to the reservoir's ownership by the city.