Chapter Two Threats
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         The objective of this section is to develop a comprehensive list of threats to eligible segments and integral structures along Route 66 in Oklahoma. It has been the experience of our team as well as others that threats to historic highways come from a number of sources.  The most obvious are threats to all highways - not just historic. These include wear and tear from motor traffic and the normal weathering processes.

        There are also threats above and beyond usage and weathering.  Many of the threats to the historic highway fabric come from highway maintenance activities.  These can include otherwise benign activities like patching and crack filling to severe effects like resurfacing and structure replacement.  The most dangerous threat to historic highways, however, is neglect.

 Known Working Model

        In his book Saving Historic Roads: Design & Policy Guidelines Dan Marriott (1998) explores in more detail some of the causes of neglect of historic highways.  He draws a distinction between physical threats that erode the integrity of historic roads and the attitudes of decision makers that give rise to these threats.  The physical threats can be grouped into four categories: realignment, destruction, replacement, and regional threats.  The attitudes crystallize around three “issues:” Safety, liability, and ignorance. 

        Though Marriot’s model deals with all types of historic roads, it does provide us with a heuristic device in which to frame our discussion of threats to historic segments of Route 66.  For the purpose of this discussion it will be useful to quote his definition of each of the four types of physical threat to the integrity of historic highways (Marriott 1998:25-29).



Realignment refers to the adjustment or movement of the path of the current road.  Realignment means that the beginning and ending points of the proposed work tie back into the existing road – in other words, a segment of roadway is to be rebuilt in a different location.  Realignment may be as simple as a shift in the lanes to soften a sharp curve or as destructive as several miles of new road abandoning the original alignment.  Often realignment is a response to real safety problems – the straightening of a curving stretch of road associated with a high accident rate, for example.  But sometimes realignment is a reaction to perceived safety problems – the same straightening based on an undocumented belief that such curves are unsafe.  Occasionally realignment can be due to other factors such as a change in vehicle use, speed, or volume necessitating a wider or more level road.



Destruction refers to the complete removal of a historic roadway or roadside element.  There are two key types of destruction that you may encounter – complete or incremental.  The loss of an entire historic road at one time would be complete destruction. It is possible that the same destruction could occur over a period of years or even decades through systematic changes, destroying or modifying portions of the original road – for example, the widening or travel lanes, addition of shoulders, or removal or trees – to a point at which the entire road is lost.  Such incremental destruction can be the result of a concerted policy to rebuild the historic road, or it can occur simply through responses to seemingly unrelated events and policies that, taken in total, lead to the loss of the historic resource.


The replacement of road and roadside features deserves careful attention.  A historic road is actually a collection unique details – cobbled gutters, brick pavement, stone bridges, art deco lighting, signs, wooded areas, stone outcroppings and exquisite concrete balusters.  These are all details that, taken in total, provide the richness of the experience.  Occasionally, time, wear, or even accidents may necessitate the replacement of an element or elements of a historic road.  Every effort should be made to replace roadway and roadside elements with like materials, constructions, and forms in their original locations.  The replacement of any historic road feature with one of inferior aesthetic quality, material, or finish chips away at the historic integrity of the route (incremental destruction).

Regional Threats

Regional threats and issues address the broader landscape and community associated with the historic road.  What is the nature of the landscape through which the road passes? Is it wooded? Urban? Suburban? Does the historic road wind along a river gorge or pass though the Great Plains?  Are nearby billboards impacting the visual integrity of the route? Is a new highway planned to cross or pass over or under your historic road?


Regional threats may originate well beyond the actual historic road itself.  Has a sudden increase in populations generated increased traffic on the historic road?  Does the historic road provide direct and easy access to a new employment area, thus generating commuter traffic? Is a new facility adjacent to the historic road going to visually impact the historic road or generate an increase in traffic? Are historic view or vistas threatened by any changes?



According to Marriott there are three “driving forces” behind these threats to the historic integrity of Historic Roads.  These forces create an attitude or climate in which the four physical threats outlined above can flourish.  These forces or “issues,” as he characterizes them, are safety, liability, and ignorance.   

Safety is not a new issue to historic preservation.  It is often invoked to speed up the condemnation process and demolition of historic buildings in marginal urban neighborhoods and business districts. In the case of historic roads, transportation agencies often invoke “public safety,” when they plan to destroy or modify an old road or historic highway that is perceived as unsafe.  The issue, however, is whether the safety issue is real or perceived.  Replacing a two lane historic road with a updated two lane or a four lane road may, in fact, increase both traffic and traffic speed.  This often results in more traffic accidents than with the original road (Marriott 1998:23).  Restoring and maintaining the original cross-section and alignment should be one of the alternatives or options in a planning document or feasibility study. 

Riding on the tail of safety is liability.  According to Marriott (1998:24) historic bridges are particularly vulnerable to this issue. Where lane width is narrower than is acceptable by current standards or the bridge structure supports lighter loads than its modern replacements government agencies often move toward demolition to avoid potential litigation. 

            The issue of ignorance needs little explanation.  Most destruction and neglect of historic roads, as with other historic resources, is due to a lack of understanding of their value.   Often, transportation and planning agencies are unaware that these historic resources powerful legacies that give meaning to our lives.  The public does not become aware of this fact until a resource is lost.   


Oklahoma Route 66 Experience 

The model provided by Marriott provided us with some background in which to frame our experience along Route 66 in Oklahoma.  This study is more ethnographic than longitudinal in nature.  In other words we are only taking a snap shot in time and not studying the effects of various forces on the historic resources over time. 

The methods we used in gathering information were simple.  Between March 7 and 11, 2002, and December 18, 2002 we inspected each of the 45 listed or eligible properties along Route 66 in Oklahoma.  We took photographs and videos of each resource and documented their condition. In addition, with the assistance of Melvena Heisch, Jim Gabbert, and Charles S. Wallis, we developed a list of individuals to contact concerning their observations of conditions along Route 66. 

During the course of our investigation we encountered a number of physical threats to the eligible segments that would compromise the historic integrity of each.  We developed a matrix to summarize our observations and to lay the groundwork a management plan.  This matrix can be found in Table 2.  The following discussion will focus on the elements of that matrix.


Explanation of Matrix Elements 

The “road is the resource” and all the eligible segments and integral structures along route 66 in Oklahoma (except the Ozark Trail Obelisk, the pedestrian underpass in El Reno, and the railroad trestle east of Weatherford) were paved with either concrete, asphalt, brick, or in the case of one bridge, wood decking.  In a number of instances we encountered pavement deterioration.  In almost all situations this was due to some form of weathering that was not being addressed by maintenance.  In one situation the maintenance procedures contributed to the deterioration of the historic roadbed. 

We developed a number of categories on our Matrix of Threats in which to document these conditions.  The following discussion is intended to explain the categories in the Matrix of Threats in more detail. 

Observed Traffic Volume           

Ironically, this is most likely the biggest threat to any road or bridge.  Though built for traffic, vehicles traveling on the road degrade the resource.  The scope of this study did not call for a detailed evaluation of traffic volume.  Though various people interviewed suggested that some count data for portions of the road did exist we were unable to obtain them during the course of this study.  The reader should note that we do recommend that accurate traffic counts be taken in the future on portions of the route where listed or eligible segments exist.  Since traffic volume is a significant threat to any historic highway and its integral structures we did consider traffic volume in this study. 

    As mentioned above this is not a longitudinal study.  The study team spent only a few days on historic Route 66 and made observations. Consequently, the impressions logged under “Observed Traffic Volume” are anecdotal at best, but they did help us in making important observations about traffic volume patterns. 

There is a distinct difference in traffic volume along signed segments of historic route 66 in Oklahoma between the portion of the highway east of Oklahoma City and that portion west of Oklahoma City.  East of Oklahoma City the designed historic route 66 runs almost parallel to Interstate 44.  Interstate 44, however, is also a toll road through most of this area.  Traffic volume is considerably higher along this segment.  This may be due to the fact that many vehicles are taking the old four-lane Route 66 to avoid tolls. However, it is more likely that traffic is very heavy along this transportation corridor.  Oklahoma’s two largest cities, Oklahoma City and Tulsa, are located along this corridor.  Commercial traffic is heavier in this part of the state.  Thus the historic road functions as alternative route when traffic is heavy on the interstate. 

Route 66 west of Oklahoma City also runs parallel to Interstate 40.  Municipalities along this stretch of highway are much smaller than along the eastern portion of the route.  The interstate here is no longer a toll road and all traffic uses it freely.  In addition, the route designated as historic Route 66 is a two-lane highway throughout its entire length.  This in contrast to the eastern portion which contains numerous four lane segments. 

Though we were unable to obtain traffic count data for any segments of Route 66 under its jurisdiction we did enquire if the Department of Tourism had any information on the amount of tourists who travel Route 66.  At this time they had no system set in place to evaluate tourism volume along the historic route.  It should be noted, however, that the Route 66 Museum in Clinton takes daily counts of visitors.  This provides some insight into a “threshold” count for traffic on Historic Route 66. 

            In examination of Table 2: “The Matrix of Threats” the reader will notice that the investigation team rated traffic on resources along a continuum from “none” (as in the case of the Eleventh Street Bridge over the Arkansas River in Tulsa) to “extremely heavy” (as in the case of the Horse Creek Bridge in Afton). These ratings are based upon our impressions as we documented and photographed each resource.  Consequently, they are purely subjective.   

            One last observation, except for Horse Creek Bridge and the twin bridges over Bird Creek, all other eligible resources along the portion of historic Route 66 east of Oklahoma City were on early segments of Route 66.  They are not on the main line that is used as an alternate to Interstate 44.   Consequently, traffic on these resources was light. Horse Creek Bridge and the twin bridges however, are on the main line and thus experience considerably more traffic.  This bridge has very narrow lanes.  Though in good condition overall, it would not surprise this team if there were plans in the future to replace this structure.  


Threats Particular to Roadbeds and Decking 

            As mention earlier the road is the primary resource of any historic highway.  There are three primary characteristic of a roadway: alignment, profile, and cross-section.  In the case of historic roads a fourth can be added: fabric.  Alteration or damage to any one of these basic characteristics of a road could be considered a threat.  A brief description of each is necessary here.



The general route of a road fixed on the landscape is considered its alignment.  This includes its curves, intersections, and straight sections


The way a road or highway changes grade along its alignment is known as its profile. The profile follows the centerline of the highway and is a record of the change in grade.  This includes hills, valleys, and any change in elevation of the road surface.


The horizontal placement of road elements is considered the cross-section. The cross-section extends from the right of way through the shoulder and pavement across the road into the opposite right of way.  It includes pavement elements like the apron, shoulder, road surface and subsurface materials.  It can also include drainage systems features as well as signs, markers, and guard rails.

Fabric or


The material that makes up the roadway itself.  For example, gravel, stone, planks, concrete, bricks, or asphalt (asphalt). Our experience of Route 66 in Oklahoma we found gravel, concrete, brick, asphalt, and in the case of the “Little Deep Fork Bridge” decking – planks.


Threats to these resources include realignment, replacement, and total destruction.  Our investigation of the Forty-five historic resources under consideration in this study suggests that two addition threats should be included: cracking pavement and improper maintenance.   

During this investigation we encountered a number of threats and threatening conditions that were placing the historic road and bridge decks in jeopardy. These can be seen in Table Two: “Matrix of Threats to Route 66 Resources” in the column entitled “Threats Particular to Roadbeds and Decking.”   

The dominant observation of roadbed and decking on eligible segments was that the pavement was cracking.  Cracking of pavement can be caused by a number of factors.  There are two primary ones, however, one caused by nature and one caused by human activity.  Weathering is a natural process in which differential freezing and thawing of water collected in minute cracks and seams during the winter and summer season will cause any type of fabric or pavement to crack.  Excessive heat can also cause buckling of the pavement.   

Vehicular traffic, in particular heavy commercial vehicles, are the major cause of cracking of pavement even in modern highways.  This cracking in conjunction with weathering can result in rapid deterioration of the existing fabric or pavement. 

Improper maintenance can cause both cracking and deterioration of the existing fabric.  One case in particular stands out here.  The “Miami Original Nine Foot Segment” has been covered with gravel.  This segment of original nine-foot wide roadway is paved with Portland cement.  It appears to maintenance crews have decided to widen the cross section by grading an apron on each side of the roadbed and pouring gravel over both dirt apron and cement pavement.  Vehicles driving upon this narrow segment of road exacerbate the situation by grinding the gravel into the pavement. 

Threats Particular to Bridges 

Bridges have the same basic design characteristics as does the roadbed.  In other words, basic design characteristics of a bridge include alignment, profile, cross-section and fabric.  In this study 25 of the 45 resources under investigation were bridge structures.  In our observations we encountered some threats we considered particular to bridges. These we organized into three basic categories: threats to substructure and supports; threats to superstructure members (in most cases truss elements); and finally threats to rails and safety elements. 

The most common threat to elements in all three of these categories was rust.  The most severe case of rust affecting all elements was found on Bridge No. 18 over Rock Creek in Sapulpa.  The second most severe was the Pryor Creek Bridge near Chelsea.  

            Besides rust substructure elements appear to be subject to erosion problems.  The shifting of creek beds and seasonal fluctuation of water levels appears undermine some bridge structures.  One bridge in particular – Resource 77 over an unnamed creek is in serious condition.  The concrete pylons which support the bridge supports are being undermined and exposed by erosion from the currents in the creek. 

            We also encountered a number of bridges in which the guard or safety rails were either rusting away or damaged by traffic accidents. The bridge just east of the town of Hydro (Resource 79) is an excellent example of this.  Though the rails are concrete, they appear badly damaged by traffic accidents.


Threats Particular to all Resources 

            The study team encountered three basic threats particular to all resources during the course of this investigation.  This first is vandalism. A number of resources were covered with graffiti.  One resource in particular – the Ozark Trail Marker was covered extensively with various colors of paint.  In addition the concrete base appears to be chipped – presumably the result of being struck by a motor vehicle.  

            The second generalized threat we refer to as “modern applications.”  It appears that bridges in particular are often used as supports for utility lines and pipelines.  A good example of this is the Bridge over the Canadian River where a number of pipeline presumably containing electrical or phone wiring is attached to the south face of the deck supports.  Other modern applications include barbed wire fencing to restrain cattle and riprap to shore up eroding creek and riverbanks, and the removal of bridge support members as in the case of the Tiber Creek Bridge. It appears that the portal struts were removed presumably to provide clearance for modern semi tractor-trailer trucks. 

            The final generalized threat we encountered was flooding.  In one case, “Bridge No. 18 at Rock Creek” in Sapulpa, appears to be subjected to periodic flooding.  The adjacent railroad bridge has a deck and track supports higher than the vehicular traffic bridge.  The substructure members beneath the railroad bridge were filled with tree branches and other debris suggesting recent flooding.  Examination of Table Two shows that this bridge has extensive damage in all areas.


Threats to Unique Resources 

            There are some resources that need special attention.  The Ozark Trail Marker (Resource 46) on a section of the original alignment of Route 66 between the towns of Chandler and Stroud is a particular case in point. This resource is located in a small triangular patch of ground where the intersection of two roads forms a “T”.  In this case the “T” configuration is more like a Ñ configuration with the Tail Marker in the center.  The roads that form this intersection have a sand and gravel surface.  They are local county roads and the Trail Marker is within the right of way.   

Inquiries into the ownership of this resource proved interesting.  The Lincoln County Assessor, Randy Wintz, was very familiar with the resource and its peculiar location.  He informed us that all private property lines run down the center of local roads.  The county, however, has control and responsibility for the right-of-way.  It was not clear to him who would actually own the Trail Marker, or who would hold sole responsibility for its welfare. Historic documents collected by local residents suggest that Lincoln County owns this landmark.  Confusion, over jurisdiction and ownership among county officials can result in damage or destruction of the resource.