National Park Service U.S. Department of the Interior

Resource History and Description of Existing Conditions
Upper Gate House road is also Telford. However, the road from the White Bridge to the Great
Circle, based on past federal highway work, appears to be a macadam type road. The original
cross road was a crushed-stone surfaced road, not truly Telford or macadam. 1082 True Telford
design differed from macadam design. 1083 Both paving technologies had become standardized
by the first quarter of the nineteenth century.
Macadamized pavements differed from mere gravel surfaces because they met a detailed
set of specifications that employed varying-sized stones in a designated pattern. 1084 Invented by
John Loudon McAdam (1756-1836), macadamized pavements used a deep layer of small, hard,
and irregularly shaped stones that bonded together under the pressure of traffic and formed a
solid, yet resilient road surface. Surfaces were constructed with a slight crown to allow drainage,
and thus prevent rainwater from pounding the roadway. 1085 McAdam's design represented a
less-expensive variation of the paving method of Scottish-born civil engineer Thomas Telford
(1757-1834) who advocated a solid rock foundation that supported a surface of smaller crushed
stone, a design used primarily for early nineteenth-century military roads. 1086 In addition, with
Telford's roads, a drain crossed under the bed of the bottom layer to the outside ditches every
hundred yards to help keep the road hard and dry. 1087
Frederick Law Olmsted and Calvert Vaux laid out the first technically correct macadam
pavements in the United States in Central Park in 1858. By the end of the nineteenth century,
the invention of both stone crushing machinery and steam rollers made macadamized roads far
less expensive than before. Macadamized pavements provided a surface smooth enough for
easy traction, yet rough enough to allow a horse a foothold. They were particularly suited to
lighter vehicles, such as the pleasure carriages of the very rich, because heavier vehicles like
wagons created ruts in the roadways. 1088 A late-nineteenth-century alternative to macadamized
roads would have been asphalt. The first asphalt street was laid in Newark, New Jersey, in 1871.
By 1900, chemists had found a way to produce artificial asphalts that were far less costly than
imported natural asphalt. Cities such as Washington, D.C., Buffalo, San Francisco, New York,
and Philadelphia had all begun to pave with asphalt by the end of the nineteenth century. 1089
Some Vanderbilt roads are also distinguished by their curb and gutter system of cast
concrete. Curradi describes these as "precast concrete curb[s] 4" wide and 4" exposed on both
sides of the road." 1090 Again, recent road work on the property revealed that both the curb and
1082
Comments to author, August 18, 1999, Henry Van Brookhoven.
1083
In an article in The Engineering Record about the Twombly estate, the roads there are described as
being "built of macadam, with a telford base, and [being] mostly 16 or 18 feet wide." ("The Twombly
Estate," The Engineering Record [6 February 1897]: 207.)
1084
Clay McShane, Down the Asphalt Path, The Automobile and the American City (New York: Columbia
University Press, 1994), 58.
1085
Donald C. Jackson, "Roads Most Traveled, Turnpikes in Southeastern Pennsylvania in the Early
Republic," in Early American Technology, Making and Doing Things from the Colonial Era to 1850 ed.
Judith A. McGaw (Chapel Hill: University of North Carolina Press, 1994), 210.
1086
Carroll Pursell, The Machine in America, A Social History of Technology (Baltimore: Johns Hopkins
University Press, 1995), 66-7; Jackson, 210.
1087
http://www.worldwideschool.org/library/books/hst/biography/TheLifeofThomasTelford/chap17.
html
1088
McShane, 58.
1089
McShane, 61.
1090
Historian's Research Notes File, 74. Source: Curradi.
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