A small portion of road parallel to Kingston Road is called Old Kingston Road running near the Highland Creek, east of Morningside Avenue. There is a discontinuity and a large reduction in capacity as the road reverts to the original route at an interchange with Military Trail, where traffic is defaulted onto Highway 2A, which was constructed in 1947 as a precursor to Highway 401, and later became a spur when that highway was extended westwards along a more northerly alignment. To facilitate traffic to and from Highway 401, and to preserve the historic village of West Hill, the spur was retained and Kingston Road was never widened and reconnected as a through street, despite having six lanes on either side of West Hill. Other former, parallel sections also called Old Kingston Road, exist in Ajax and Courtice, although Kingston Road proper does not reach Courtice today. There is also an old section of the old Danforth Road in Grafton.