Numerous other modifications have been made to the original parkway over the decades. The most obvious change has been the erection of miles of steel guardrails alongside the roadway. For most of its length, opposing traffic lanes were separated by w-beam or box-beam guardrail. Shoulders and bridge abutments were also protected with box-beam, and in some cases, w-beam guardrail. The timber guardrail parapets of the original girder bridges were replaced with double lengths of box-beam guardrail and the wood facing along the girders was removed. On many bridges, such as the Park Avenue Viaduct and Ardsley Road Bridge, steel posts and railings have been added to the top of the bridge parapets. Decorative openings in the bridge parapets have been protected by steel railings as well. Reinforced concrete barriers dividing opposing traffic lanes were added to the Woodland Place Viaduct and the Crane Road Bridge. The Valhalla Bridge was modified to carry only northbound traffic, and a new bridge was built nearby to carry the southbound lanes. The new bridge, constructed of girders, is out of character with the original parkway bridges, with no stone facing and a chain link fence on its walls. Concrete barriers were added to Valhalla Bridge to reinforce its west parapet and to divide the roadway from the sidewalk on the east side of the bridge. The parkway lighting that was so meticulously designed as a rustic feature was systematically replaced by modern steel lighting standards. In 2001, a lone rustic cedar lamppost remained near the Ardsley Road Bridge. A few timber fences remained along the footpath near Butler Woods. Only one original rustic footbridge was still standing, and many of the new bridges featured no rustic details. Grass roots efforts, however, have continued to make improvements in restoring the parkway. In 2002, the Garth Woods Conservancy raised private funds to sponsor the construction of a new rustic locust footbridge at the site of the existing rustic A-frame bridge, below the Ardsley-Popham Bridge on the northern edge of Garth Woods. This bridge followed the design of original footbridge designs, except it used 1" diameter steel bolts at the pin connections.

The parkway’s historic landscape design has also been altered. One of the most notable but subtle alterations had been the loss of visual contact with the Bronx River due to changes in alignment, vegetation, and the addition of various structural barriers that interrupt planned sightlines between the main drive and the river. This transformation was particularly unfortunate given that Merkel had repeatedly emphasized that the river was to be the "dominant motive" in the parkway’s design. By the end of the twentieth century, motorists no longer had an intimate experience with the river throughout most of the drive. Many planned views of the river were blocked by overgrown vegetation. In other cases, such as immediately north of the Hamilton Street Bridge and along the southbound lanes in Garth Woods, the view of the river was obstructed by reinforced concrete safety barriers. One of the most dramatic vistas in the BRPR, the southbound view of the Bronx River and Harney Road Bridge, was almost obscured by concrete barriers and overgrown vegetation. Trees were planted on both banks of the river, both north and south of the Harney Road Bridge, which further obscured the charming view of the river and bridge. Many of the original pathways were also removed. The main parkway path south of White Plains and into Scarsdale was removed with the reconstruction project in 1967 and was not replaced. Bicyclists and walkers used the adjacent local streets to travel between the disconnected parkway paths.