Turnpikes Past and Present
The construction and maintenance of a superhighway involves
inputs from many fields - politics, science, technology and
engineering, mapmaking, landscaping, to name just a few. The
politics of planning the route of a proposed highway can be the
subject of bitter controversy, especially when the route traverses
heavily populated areas such as our part of New Jersey. With the
planned route set, the engineers must consider the terrain and
how it affects the sharpness of curves, steepness of hills, etc. as
well as the right-of-way, which includes the land surrounding the
actual road surface, the shoulders and drainage ditches etc.
Landscaping considerations include possible plantings to control
erosion around the roadbed, as well as to minimize the monotony
for the driver. The latter can be important factor in today''s sleep-
After clearing the right-of-way, the engineers must determine
whether the existing soil is suitable as the "subgrade" or whether
additional earth of another kind must be hauled in to make a
suitable substrate on which to build the roadway. After
compacting the subgrade a "base course" of some 6 to 8 inches
or so is laid down. The "surface" is then laid down in a thickness
that depends on the kind of traffic expected. A superhighway
needs a hard surface, the "pavement". The two most popular
pavements are concrete and my favorite, macadam. We owe the
latter to a Scotsman named John Loudon McAdam, who was
Britain''s master roadbuilder back in the early 1800s.
McAdam appears to have been the first to appreciate that dry soil
could support heavy traffic, with pavement serving the functions
of providing smoothness and keeping the soil dry. His macadam
was composed of packed thin layers of crushed rock. Today''s
macadam consists of the crushed rock with added asphalt, tar or
other materials to fill in the spaces in order to provide watertight
seal and also to bind the particles of rock together. McAdam
would no doubt be amazed to see the types of vehicles that now
travel over his surfaces.
Highway materials and designs are still subjects for researchers
hoping to improve the durability of our highways, which now
have to contend with multi-unit trucks and those horrid SUVs
(author''s personal and oft-stated evaluation). The Federal
Highway Administration''s Turner-Fairbank Highway Research
Center is one institution that carries on research in this area.
All this rumination on superhighways was brought about by my
experience last week driving on what was this nation''s first
superhighway of any substantial length, the Pennsylvania
Turnpike. Our trip to western Pennsylvania, to attend our
beloved Annie''s funeral services, involved driving from Carlisle
to Donegal on the Turnpike in a driving rainstorm in my little
1997 Volkswagen Jetta. On a sunny day this drive can be
enjoyable, with scenery similar to what you might see in Ireland.
On a rainy day, however, the drive can be hellish. For those who
haven''t experienced this section of the Turnpike in inclement
weather, a little history might give you a better appreciation for
one safety feature built into many of our modern superhighways.
That feature is the wide median separating opposing lanes of
To bolster my own knowledge of Turnpike lore, I consulted my
trusty 1962 world Book Encyclopedia, as well as a Web site
pumpwarehouse.com. I was surprised to find that the first
turnpike, a road for which a toll is charged, dates back some
4,000 years. Historical records show tolls being collected for a
Persian military road between Babylon and Syria in those early
days. In our own hemisphere, the World Book credits the Inca
with building an astonishing 10,000 miles of roads connecting
their cities. Coincidentally, I have just finished reading an article
titled "Empires Across the Andes" by Virginia Morell in the June
2002 issue of National Geographic. This article deals in part
with the Wari, a much earlier, longer lasting kingdom in Peru, as
being the true road builders. The article cites the Wari
"extensive system of highways that is now often erroneously
attributed to the Inca." Update your World Book.
The first section of the Pennsylvania Turnpike was opened in
western Pennsylvania in 1940. I was 12 years old and living in
Mechanicsburg, which is 10 miles from Carlisle. It wasn''t too
long before the turnpike had reached Carlisle and I remember the
excitement when the Carlisle to Pittsburgh link opened for
business. People in our area would take their autos out for a spin
on the Pike as their Sunday recreation. There were even some
reports of picnicking on the median! The stretch of turnpike
from Carlisle to the first tunnel was/is virtually curve-free and
straight, an incentive for the heavy of foot to give it a bit more
Unfortunately, in those days, neither the automotive technology
nor the human psyche was prepared properly for this newfangled
"superhighway". Motorists were burning out their engines on
this straight stretch at unheard of speeds of 60-70 mph or more.
Such high-speed travel for a prolonged period of time was new to
virtually everyone. I recall hearing and reading of accidents
caused by drivers essentially being hypnotized when following a
car on the Pike. The problem was that they would follow that car
even when it pulled off the road, say for a flat tire. The result in
a number of cases was a fatal crash, with the following car
plowing into the stopped vehicle ahead.
In those days, one of the unusual features of the Turnpike was
that, with its many tunnels and thoughtful engineering, the road
had no grades that required shifting gears. Automatic
transmissions were virtually unknown. Another novel feature
was the rest stop, with its Howard Johnson restaurant and Esso
gas station, located at convenient intervals only a stone''s throw
off the road. On those Sunday outings, you could opt for a bowl
of bean soup for a dime (vegetable soup was 15 cents) or, for
only a dollar, have your Sunday dinner of fried chicken with
soup, 3 hot veggies, salad, bread and butter, drinks and dessert
included. During the World War II years, gasoline was rationed
and using part of that ration for a Sunday dinner on the Turnpike
made it a truly special occasion.
Remember those picnics on the median? Actually, a major
design flaw lay in the fact that those medians on that first
superhighway were, and even today, are not all that common .
Over much, perhaps most, of the western section of the Turnpike,
only the common, relatively low concrete divider separates the
opposing lanes of traffic. Because of this situation, my wife and
I could well have become fatalities on our way to Annie''s
funeral. When in a heavy rain, I tend to worry about
hydroplaning, which occurs when the car loses traction and
essentially skates out of control on a film of water. (Indeed,
there was a serious hydroplaning accident that we learned had
happened that very day on another nearby highway.) Being
cautious, I slowed to about 55-60 mph. Truckers don''t slow
down one bit and they pass, throwing back a spray of water that
makes it hard to see - annoying but manageable.
However, at one point a truck coming the other way hit a deep
puddle and threw up a wall, not a spray, of water in front of it.
This mass of water leapt the divider and hit my windshield, not
only scaring the hell out me but also blinding me for at least a
second or maybe even two. This was in an area where there was
no shoulder and a divider on my right as well. I calculate that we
traveled between 100-200 feet totally blind before the windshield
cleared! Thankfully, we made it safely to our destination. Most
of today''s superhighways employ generously sized medians to
separate opposing lanes wherever possible so drivers don''t have
to contend with such hazards.
Fortunately, the fire alarm that went off at our hotel as we were
set to go to the funeral was a false alarm. However, the flat tire
that we had as we pulled out of the hotel parking lot was real!
Thankfully, our Lamb guy, Harry Trumbore, had driven his car
and was behind us. We made it to the funeral and, on a bright
sunny day, said our final farewells to Annie.
If you find this second column in a row rather light on science
and technology, I hope you understand that it has been difficult
to come up with a topic in view of the past week''s events. Next
week, I''ll try to compensate by attempting to get at least a crude
understanding of the recent theory that our universe started when
two membranes banged together. Don''t expect too much!
Allen F. Bortrum