Abstract:
A security barrier system for use with a trafficable surface and a site requiring protection from advancing vehicles includes a composite bed system having a plurality of elevations and comprising a first layer beneath a second layer. The first layer includes a deformable material configured to collapse when subjected to vehicle loads, and the second layer includes a pedestrian cover surface over the deformable material that conceals the deformable material. The pedestrian cover surface is configured to support pedestrian traffic over the deformable material without permanently collapsing the deformable material and to collapse along with the first layer when subjected to vehicle loads. A structure beyond the bed system is provided to resist the impact of a vehicle that has traversed the bed system.

Description:
CROSS REFERENCE TO RELATED APPLICATIONS 
     The present Application claims the benefit of priority as a continuation of U.S. patent application Ser. No. 11/515,080. titled “Vehicle Barrier System” filed on Sep. 1, 2006, which is a continuation-in-part of U.S. patent application Ser. No. 10/897,417, titled “Vehicle Barrier System” filed on Jul. 21, 2004, which issued on Oct. 31, 2006 as U.S. Pat. No. 7,128,496, the disclosure of which are hereby incorporated by reference. 
    
    
     FIELD 
     The present invention relates to an installed vehicle barrier system that protects at-risk sites from vehicle born attacks. The present invention of the barrier system uses a combination of a number of vehicle attenuating devices to prevent the passage of vehicles. These devices include a traffic control zone, followed by a first impact element that is backed by a bed of deformable material, and followed by a second impact element. 
     BACKGROUND 
     Barriers for restricting the passage of vehicles (such as automobiles, trucks, busses, airplanes and the like) are generally known. Barriers that are fixed in the roadway, meaning they do not move by device or mechanism, are typically categorized as “passive” or “inoperable” barriers. These types of barriers are either removably placed on the roadway or sidewalk surrounding an at-risk site, or they are installed into the ground or built into the landscape/streetscape. Known installed “passive” barriers typically include foundation walls (typically at least 36″ high), or bollards in the form of “posts” embedded in a concrete foundation, and beds of a crushable material (such as concrete). Walls and bollards are intended to stop vehicles through impact resistance, having sufficient shear strength to remain intact at impact and relying on the inertia of their foundations to bring a vehicle to a halt. 
     In addition to vehicle barrier systems, vehicle arresting systems are also known. Where vehicle barrier systems are intended to immediately stop a vehicle, vehicle arresting systems are intended to control the stopping of a vehicle over a given time and/or distance. Known arresting systems include beds of a crushable material (such as concrete), fences and gates, and cable and elastic (e.g. “bungee cord”) systems. Crushable beds tend to utilize the interaction between the bed and the tire(s) of the vehicle. As a vehicle moves across the crushable material, the weight of the vehicle causes it to sink into the bed. At the same time, the spinning of the tire “rips” through the crushable material. As the vehicle drops farther into the bed, the tires&#39; rotation tends to become slower until finally the vehicle is stopped. For example, crushable beds at the ends of aircraft runways for aircraft that “overshoot” the runway are generally known for gradually decelerating the aircraft over an extended distance to minimize injury to occupants and damage to the aircraft. Examples of such crushable bed systems are described in U.S. Pat. Nos. 5,885,025; 5,902,068 and 6,726,400. 
     These known vehicle barriers present a number of functional problems. Walls significantly impede pedestrian traffic and can cause pedestrian “herding” and “bottle necking.” Additionally, walls, and bollards as well, are somewhat visually restricting. The inherent height of the two, that is necessary for their function as a vehicle barrier, reduces the visual “openness” of the landscape/streetscape. Crushable beds are not optimal because they typically require an extended length of the crushable bed (upwards of 50 feet or more) to arrest a vehicle (and substantially longer for aircraft and the like). Such long lengths are generally not compatible with most urban applications, where space between a roadway and a building line or perimeter line is fairly small (e.g. 5-30 feet) and a primary objective of the barrier is to stop the progress of the vehicle within a relatively short distance. Such known vehicle barrier systems tend to provide limited application and flexibility to designers in providing an effective vehicle barrier system intended to meet applicable government performance standards, and is minimally obtrusive, for use in areas such as urban settings that typically have limited space for installation of such barriers. 
     Accordingly, it would be desirable to provide an installed vehicle barrier system or the like of a type disclosed in the present Application that include any one or more of these or other advantageous features:
         1. A system providing a barrier that is resistant to unauthorized breach by vehicles.   2. A system that minimizes the restriction of pedestrian traffic flow.   3. A system that provides a less visually obtrusive installed vehicle barrier system.   4. A system that stops a vehicle in the short distance between a roadway and the protected site.   5. A system that rapidly arrests a vehicle without regard to vehicle damage.   6. A system that is integrated into the landscape/streetscape, employing similar elements such as curbs, sidewalks, benches, etc.   7. A system that combines a trafficable roadway surface, a curb, a bed of compressible material covered by a surface cover layer, and a low wall line or low bollard line.   8. A system in which the required height of the impact element line is interdependent with the characteristics of the bed of compressible material, so that the various components of the system may be adjusted to suit the needs of a particular application.       

     SUMMARY 
     One embodiment of the present invention relates to a barrier system for use between a roadway and a site requiring protection from advancing vehicles. The system includes a trafficable surface and a first impact element (such as a “curb” as typically included along an edge of a trafficable surface). The trafficable surface may include certain features to reduce the speed of an approaching vehicle before reaching the first impact element. Such features include frictional elements and barriers arranged to create traffic flow patterns. Vehicles that reach the first impact element will have their trajectory redirected upwardly from impact with the curb. Beyond the first impact element is a deformable bed intended to lower the elevation of a vehicle that encounters the bed by including a material or infrastructure configured to collapse, breakaway, crush, compress, yield or otherwise deform under the weight of the vehicle when the vehicle descends onto the bed after impacting the first impact element. The bed may be contained in a confining structure such as a foundation and topped by a surface cover layer at a substantially equivalent elevation with the top of the first impact element, configured to spread the weight of loads due to pedestrian and the like. Beyond the bed a second impact element in the form of an impact element line extends upwardly from grade level, separating the barrier system from a protected zone adjacent to a site requiring protection. The components of the system may be flexibly adapted in various combinations to suit installation in a particular application while providing performance that is consistent with applicable barrier performance standards. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a schematic representation of a top view of the vehicle barrier system according to an embodiment. 
         FIG. 2  is a schematic representation of a sectional view of the vehicle barrier system according to the embodiment of  FIG. 1 . 
         FIG. 3  is a schematic representation of a sectional view of a vehicle impacting the first impact element of the vehicle barrier system of  FIG. 1  and  FIG. 2 . 
         FIG. 4  is a schematic representation of a sectional view of a vehicle jumping as a result of impacting the first impact element of the vehicle barrier system of  FIG. 1  and  FIG. 2 . 
         FIG. 5  is a schematic representation of a sectional view of a vehicle entering the compressible bed of the barrier system of  FIG. 1  and  FIG. 2 . 
         FIG. 6  is a schematic representation of a sectional view of a vehicle impacting the impact element line of the barrier system of  FIG. 1  and  FIG. 2 . 
         FIG. 7  is a schematic representation of a top view of the vehicle barrier system according to another embodiment. 
         FIG. 8  is a schematic representation of a sectional view of the vehicle barrier system according to the embodiment of  FIG. 7 . 
         FIG. 9  is a schematic representation of a top view of a vehicle barrier system according to another embodiment. 
         FIG. 10  is a schematic representation of a sectional view of the vehicle barrier system according to the embodiment of  FIG. 9 . 
         FIG. 11  is a schematic representation of a sectional view of a variation of the vehicle barrier system according to the embodiment of  FIG. 9 . 
         FIG. 12  is a schematic representation of a sectional view of another variation of the vehicle barrier system according to the embodiment of  FIG. 9 . 
         FIG. 13  is a schematic representation of a sectional view of another variation of the vehicle barrier system according to the embodiment of  FIG. 9 . 
         FIG. 14  is a schematic representation of a sectional view of another variation of the vehicle barrier system according to the embodiment of  FIG. 9 . 
         FIG. 15  is a schematic representation of a sectional view of another variation of the vehicle barrier system according to the embodiment of  FIG. 9 . 
         FIG. 16  is a schematic representation of a sectional view of another variation of the vehicle barrier system according to the embodiment of  FIG. 9 . 
     
    
    
     DETAILED DESCRIPTION 
     According to the illustrated embodiments, the vehicle barrier system provides an arrangement or combination of installed, vehicle arresting and barrier devices to be used along a security perimeter to create an area  5  protected from vehicle intrusion (e.g. to provide protection of facilities, buildings, restricted areas, etc.). This arrangement of vehicle arresting and barrier devices is intended to stop vehicles within a relatively short distance traveling at varying rates of speed, according to pre-established crash barrier rating systems and/or criteria. The vehicle barrier system is shown composed of a combination of distinct regions (shown for example as four regions). A vehicle attempting to breach the security perimeter may progressively encounter all four of these regions and each region, in turn, is intended to reduce the vehicle&#39;s speed or control the vehicle&#39;s approach and thus reduce its speed. 
     A first region includes a trafficable surface (e.g. asphalt, concrete, paving, etc.) using friction and/or traffic patterns to slow the vehicle (e.g. traffic patterns, friction elements, etc.), as the surface material can have a higher coefficient of friction than a traditional asphalt roadway. After encountering the first region, the vehicle may encounter a second region. 
     The second region includes an upwardly extending first impact element  2  (e.g. a fixed barrier, or vertical element, shown for example as a “curb,” etc.) disposed at the edge of the trafficable surface  1  or other desired location. The curb  2  is intended to reduce the vehicle&#39;s speed through inertial impact resistance. The curb  2  also serves to cause the vehicle to be directed at least partially upward (e.g. “jump”), where the vehicle&#39;s front wheels temporarily lose contact with the trafficable surface as the vehicle&#39;s trajectory is redirected upwardly from the impact with the curb. After the vehicle impacts the curb  2 , the vehicle moves upward and forward and descends upon a third region. 
     The third region includes a deformable zone  3 . The deformable zone  3  is intended to lower the elevation of the vehicle below the top of curb  2  by providing a bed  9  having an infrastructure or material that is configured to collapse, breakaway, crush, compress, yield or otherwise deform under the weight of the vehicle when the vehicle descends onto the bed after impacting the curb (see  FIGS. 5-6 ). According to a preferred embodiment, the bed  9  of the deformable zone  3  has a length  15  within a range of one foot to thirty feet, and a depth  17  having any suitable depth for containing a deformable infrastructure or material intended to lower the elevation of a vehicle that encounters bed  9  by a sufficient amount so that a structural portion of the vehicle contacts the impact element line in the event that the vehicle traverses the entire length  15  of bed  9 . However, the length and depth may have any suitable dimensions for use in combination with a curb  2  and impact element line  4  for installation in a particular application. The deformable zone  3  is shown to include a cover surface layer  7  (e.g. paving, concrete, sedum, planting, soil, etc.) disposed on the surface of bed  9 . The cover surface layer  7  is intended to spread relatively smaller bearing loads (e.g. pedestrian, horse, carts, handtrucks, etc.), so as not to substantially deflect (or otherwise fail) under such loads or deform the deformable infrastructure or material of bed  9  below. The cover surface layer  7  is designed to fail under higher bearing loads and higher impact loads resulting from vehicles (e.g. automobiles, trucks, buses, etc.) having a sufficient weight (e.g. weighing at least approximately 2,500 lbs, and either crack (in the case of, for example, concrete, paving, etc.) or deflect (in the case of, for example, sedum, planting, etc.) so that the vehicle&#39;s weight bears on the deformable infrastructure or material of bed  9  below. 
     According to a preferred embodiment, the bed  9  comprises a deformable structure (e.g. lattice, honeycomb, etc.) constructed of metal, polycarbonate, plastic, composite metal, wood, etc. and configured to breakaway, collapse, crush, sink or otherwise deform under the weight of the vehicle. The bed  9  may also comprise a material (e.g. uniform or composite), alone or in combination with a structure, having characteristics that permit the material to crush, compress, yield, displace, or otherwise deform, such as, for example, cellular concrete, metallic foam, synthetic foam, or any other suitable material of combination of such materials, having a predefined compression strength, sufficient to crush under a tire(s) of a vehicle weighing at least approximately 2,500 pounds (lbs). The vehicle&#39;s weight combined with the rotation (e.g. “spinning” etc.) of the vehicle&#39;s tires is intended to deform (e.g. collapse, crush, compress, yield, displace, etc.) the deformable structure or material  9 , so that the elevation of the vehicle “drops” or is otherwise “lowered.” The deformation of the structure or material of bed  9  tends to lower the effective height of the vehicle, as the elevation of the vehicle decreases (e.g. sinks, falls, etc.) into the bed  9 , as well as reducing the vehicle&#39;s speed, due at least in part to the friction between the tires and the compressible structure of material. The desired deformability (e.g. strength, compressibility, etc.) of the structure or material of bed  9  will generally be determined by the length  15  of bed  9  and the height  16  of the impact element line  4  (shown for example as a low wall, etc.) backing the bed, on a case-by-case basis considering the available length for placement of the bed and the available height for the impact element line  4 . For example, if the area available for the bed is relatively short, then there will be a relatively small “drop” in elevation of the vehicle within the bed (as the vehicle traverses the length of the bed) and the impact element line  4  (e.g. wall, bollard, etc.) should be relatively high (e.g. sufficient to contact a structural portion such as a chassis of the vehicle, accounting for the relatively small drop in elevation of the vehicle within the bed). Conversely, if the area available for the bed is relatively long, then there will be a correspondingly greater “drop” in elevation of the vehicle within the bed (as the vehicle traverses the length of the bed) and the impact element line (e.g. a wall, bollard, etc.) may be correspondingly lower (or in certain cases, for example, essentially non-existent) such that the height or elevation of the impact element line  4  remains sufficient to contact the chassis of the vehicle to prevent further progress of the vehicle into the protected zone  5 . 
     The deformable zone  3  of the third region also includes a confining structure  8  for containing the bed  9 . The confining structure (e.g. a concrete foundation, metal trough, wood form-work, fabric mesh, etc.) is shown to surround the deformable structure of material of bed  9 , holding it in place, so that when the bed  9  is “loaded” it deforms and the deformed structure of material of the bed  9  is generally contained by the confining structure  8 . After encountering the third region having the deformable zone  3 , the vehicle may encounter a fourth region in the even that the vehicle traverses the length  15  of bed  9 . 
     The fourth region is shown located beyond the compressible zone, and includes an impact element line  4 . The impact element line (comprised of, for example, walls, bollards, posts, planters, projections, obstacles, etc.) is shown to have a sufficient height to impact a structural portion (e.g. the chassis, etc.) of the vehicle once the vehicle has dropped in elevation due to deformation of bed  9  of the deformable zone  3 . The resistance provided by the impact element line  4  is intended to be sufficient to stop any consequential progress of the vehicle after encountering the trafficable surface  1 , the curb  2 , and the bed  9 , so that the vehicle does not enter the area  5  to be protected. 
     In the wall or line construction of conventional vehicle barriers (e.g. “anti-ram” type, etc.) impact elements are typically specified as having a height of approximately three (3) feet tall, above a finish grade elevation. For example, in the case of the U.S. Department of State (DOS), a generally recognized national authority on vehicle barrier rating and authorization, “passive anti-ram” type impact barriers are specified to have heights within the range of 30-39 inches tall, (such as described in DOS design specifications DS-1, DS-7, and DS-50 for use with a “rigid” trafficable surface (e.g. roadway, etc)). According to the illustrated embodiment of the present invention, the height  16  of the impact element line  4  may be “lowered” or reduced by an amount corresponding to the deformability (e.g. compressibility, etc.) characteristics of the bed  9 . The greater the deformability of the material, the greater the degree of deformation and corresponding “drop” in elevation of the vehicle when the vehicle encounters bed  9 . As the bed&#39;s capability to deform (e.g. collapse, breakaway, compress, crush, yield, etc.) and thus lower the elevation of a vehicle increases, the height  16  of the impact element line  4  necessary to contact the chassis of a vehicle tends to decrease. The deformability of bed  9  serves to lower the effective height of a vehicle prior to encountering the impact element line  4 . As the approaching vehicle encounters the bed  9 , it drops below the grade of trafficable surface  1  or the height of curb  2  (based on a particular application), as its wheels “grind” through or deform the structure or material of bed  9  and the vehicle&#39;s inherent weight causes the material to deform under the bearing load of its wheels. As a result, in the event that the vehicle has traversed the length  15  of bed  9  and reached the impact element line  4 , the elevation of the vehicle has been lowered in relation to the finish grade and the height  16  of the impact element line  4 . The reduction in elevation of the vehicle is believed to be attributable to the length  15  of bed  9  and to the strength characteristics (e.g. yield, compressibility, deformability, etc.) of the structure or material of bed  9 . 
     According to a preferred embodiment, the length  15  of bed  9 , and the deformability of the structure or material and the height  16  of the impact element line  4  are related in an interdependent relationship and may be combined in a wide variety of combinations and permutations to accomplish the intended objective of providing an effective barrier system that is suitable for use in locations with reduced space and that provides an aesthetically and architecturally pleasing appearance. As previously described, a typical minimum height of a conventional “anti-ram” type impact element for use in connection with a conventional roadway is approximately three (3) feet. The use of the bed  9  in connection with the curb  2  and the impact element line  4  permits the height  16  of the impact element line  4  to be reduced below the conventional standard of three (3) feet, by an amount generally corresponding to the “drop” in vehicle elevation resulting from the length  15  and or the strength characteristics of the structure or material of bed  9 . For example, if the strength of the structure or material of bed  9  is increased, then the length  15  of the bed and/or the height  16  of the impact element line  4  can be increased accordingly. Likewise, as the strength of the structure or material of bed  9  is reduced, then the length  15  of bed  9  and/or the height  16  of the impact element line  4  may be reduced. According to a preferred embodiment, the height  16  of the impact element line  4  for use in combination with bed  9  and the curb  2  is within a range of approximately six (6) inches to thirty (30) inches, however, other heights of the impact element line above the finish grade elevation may be used to suit an installation for a particular application, such as within a range of approximately zero (0) inches above grade to several feet or more above grade. 
     According to any preferred embodiment of the present invention, the interaction of the length  15  of bed  9 , and the strength characteristics of the structure or material of bed  9 , and the height  16  of the impact element line  4  is intended to provide an adaptable barrier system configured to ensure that the chassis of any vehicle that traverses the length  15  of bed  9  will come in contact with the impact element line  4 . The barrier system of the present invention is intended to avoid the use of conventional approaches that include high walls, large impact elements and/or long expanses of crushable material. The embodiments of the present invention disclosed herein are intended to provide an adjustable and adaptable system comprising combinations of “stages” or “layers” of protective elements that provide flexibility to designers for adaptation to various applications having needs such as small installation areas, required pedestrian access, or when the barrier system is desired to be unobtrusive and to minimize the appearance of the barrier from detracting from (or drawing attention from) the surroundings. 
     In conventional barrier applications involving a “rigid” trafficable surface, the typical height of an impact element that is necessary to contact the chassis for most “high threat” type vehicles is approximately 18 inches. Accordingly, the Applicants believe that the height of an impact element line used in combination with a bed of a deformable structure or material according to the present invention, may be reduced by an amount corresponding to the drop in elevation experienced by the vehicle as it traverses the bed. For example, if a bed of a deformable structure or material is configured to provide a drop in elevation of the vehicle by twelve (12) inches, then the height of the impact element line may also be generally reduced by a corresponding twelve inches, in order to maintain the height of the impact element line at an effective height of 18 inches with respect to the vehicle. 
     Referring to  FIGS. 1 and 2 , the vehicle barrier system  11  is shown according to one embodiment. The system is shown to include a trafficable surface  1 , over which all vehicles can generally pass. A first impact element shown for example as curb  2  lies along the trafficable surface  1  and is backed by a compressible zone  3  and a second impact element shown as an impact element line  4 . The impact element line  4  is shown to separate the barrier system from the protected region  5 . Beyond the protected region  5  is shown the asset  12  (e.g. building, etc.) that is intended to be protected by the barrier system. The trafficable surface  1  may form a part of the barrier system by modifying its surface through addition of frictional elements (e.g. paving, aggregates, etc.) that allow it to contribute to the attenuation of an advancing vehicle. 
     According to a preferred embodiment as shown in  FIGS. 7 and 8 , the first region including trafficable surface  1  can be comprised of three distinct sub-regions. Trafficable surface  1 A is separated by a generally upright impact element (shown as a vertical element line  1 B) from trafficable surface  1 C. In this embodiment, vertical element line  1 B (e.g. wall, bollard line, wall segment line, median, curb, tree line, planter, line of benches, etc.) serves to reduce the speed of vehicles attempting to breach the barrier system. The vertical element line  1 B tends to reduce a vehicle&#39;s speed by “forcing” a vehicle to drive around the vertical element, causing the vehicle to reduce speed to maintain steering, or to drive through the vertical element, causing the vehicle to reduce speed through impact or vehicle damage or destruction. Additionally, trafficable surfaces  1 A and  1 C can be modified through addition of a frictional element (e.g. paving, aggregate, etc.) that is intended to improve the ability of the trafficable surfaces to contribute to the reduction in speed of an advancing vehicle. 
     In the embodiment shown in  FIGS. 1 and 2 , trafficable surface  1  can also be modified to become a vehicle attenuating device by changing the surface composition to a material (e.g. pavers, concrete or asphalt with added aggregates such as sand or stone, etc.) that has a higher coefficient of friction than a standard roadway wearing course. The curb  2  is intended to reduce the speed of the vehicle through impact, and also cause the vehicle to “jump”. According to the embodiment, when the vehicle reaches the deformable zone  3 , it not only bears on bed  9 , but it also descends upon the surface cover layer  7  and bed  9  with a generally vertical impact force, (as shown schematically in  FIG. 5 ). The first impact element in the form of the curb  2  may be formed of stone, reinforced concrete, wood, etc. As well, the curb may be capped with steel and/or pinned to a foundation below (not shown) for additional strength. According to a preferred embodiment, the curb  2  has a height that is typically in a range of approximately 3 inches to 12 inches high above the level of the trafficable surface, but may be provided with any suitable height for use with a barrier for intended vehicle types. 
     According to the illustrated embodiment the deformable zone  3  comprises a surface cover layer  7 , a bed  9  having a deformable structure or material for lowering the elevation of the vehicle, and a confining structure  8 . The top of surface cover layer  7  (e.g. formed from a material such as concrete, brick, pavers, tiles, cobble, planting, soil, sedum, sand, wood, plastic, etc.) is shown at approximately the same elevation as the top of the curb  2 . Surface cover layer  7  serves to spread relatively small bearing loads so that bed  9 , below, does not substantially deform, thus allowing pedestrians and the like (e.g. horses, light vehicles such as golf carts, hand trucks, etc.) to travel over this region of the vehicle barrier system without deforming the structure or material of bed  9  below. According to a preferred embodiment, the structure or material of bed  9  is designed to fail (e.g. deform, crush, collapse, compress, breakaway, yield, deflect, etc.) under loads generally equal or greater to the loads created by the tires of a vehicle having a weight of approximately 2,500 lbs. According to alternative embodiments, the bed may be configured for suitable deformation with vehicles having other loading conditions as determined in a particular application. 
     According to one preferred embodiment the bed  9  comprises a compressible material formed from cellular concrete having a compression strength within the range of approximately 30 pounds per square inch (psi) to 60 psi and formed with a substantially uniform density, such as may be commercially available from the Engineered Arresting Systems Corporation of Aston, Pa. According to an alternative embodiment, the compressible material may be other suitable materials (e.g. wood, plastics, metallic and/or polymeric materials, etc.) that are configured to crush or collapse under a predetermined loading condition, or may have different or other strength characteristics, or may have variable density (such as by containing voids of air ranging in sizes from small to large). For example, the material may be a metallic or polymeric material formed with a plurality of voids therein, such as a metallic foam or synthetic foam material, or any suitable combination of such materials and configured to compress or crush under predetermined loading conditions. By further way of example, the bed may comprises a structure configured to deform under predetermined loading conditions, such as a framework, lattice, honeycomb, or other deformable support structure and constructed of any suitable material such as metal, polycarbonate, plastic, composite metal, etc. According to other alternative embodiments, the material may be a generally incompressible material that is configured to deform under certain predetermined loading conditions, such as a liquid, slurry, gel, or other suitably deformable material. 
     The bed  9  is shown contained by a confining structure  8 . According to a preferred embodiment, the confining structure is provided in the form of a reinforced concrete foundation (e.g. trench, pit, etc.). According to other embodiments the confining structure may be formed from a metal trough, wood form-work, fabric mesh or other suitable material. The confining structure  8  is intended to retain the structure or material of bed  9  so that when the structure or material deforms, the confining structure  8  restrains the structure or material. For example, when the material comprises a cellular concrete material, the material crushes “in place,” thus the need for “empty pockets” in the confining structure and other supporting foundations (not shown), to accommodate for any displaced material can be minimized or avoided. 
     Referring to  FIGS. 3-6  the impact element line  4  is shown as a “foundation” type impact element where the structure of the impact element extends below grade and “links” (or is otherwise coupled) to a relatively significant subsurface foundation such as, for example, the confining structure  8 , a building foundation, or the like). Such foundation type impact elements are intended to provide a relatively “heavy” ballast material below grade to minimize the volume of the impact elements above the trafficable surface, thus increasing the ease of pedestrian access and minimizing visual obstructions along the security perimeter. 
     According to one embodiment, the impact elements are “bollards” formed from a shell of material (e.g. steel, etc.) having a cavity containing a fill material (e.g. cement, reinforced concrete, metal, stone, wood, plastic, etc.). The shell may include internal braces (not shown), such as steel plates, to provide additional strength. The shell and fill material may be integrally formed with a foundation below grade so that loading from vehicle impact upon the impact elements can be transferred to the foundation. Use of foundation type barriers are generally desirable for installed “permanent” type barrier systems, in which the impact elements are intended to be present for an extended time period. According to one embodiment the foundation impact elements include a steel shell filled with reinforced concrete and having a minimum cross section area of approximately 144 square inches. According to an alternative embodiment, the foundation impact element line is a wall or line of wall sections having a thickness up to and including approximately 12 inches. In the embodiments where the impact elements of the impact element line  4  are bollards or walls, the height of said impact elements is intended to be smaller than the typical 30 inch height of most conventional vehicle “anti-ram” type barriers. The height of the impact element  4  may be lower than a typical “standard height” barrier because the impact elements are backing the deformable zone  3  that tends to lower the effective height of threatening vehicles. According to an alternative embodiment, the impact elements may be provided in various shapes, sizes and materials. For example, the cross sectional area may be decreased with the use of higher strength materials or the cross sectional area may be increased with the use of lower strength materials, etc. According to another alternative embodiment where the impact element line is made up of bollards, the bollards may be connect by beams (e.g. steel, concrete, reinforced concrete, wood, etc.). According to a further alternative embodiment where the impact element line is made up of bollards connected or linked by beams or low walls, these impact elements may be covered in a suitable pedestrian seating material (metal, wood, concrete, glass, etc.) and used as a bench or other suitable article. 
     According to a particularly preferred embodiment the trafficable surface  1  (e.g. roadway, parking lot, etc.) includes trafficable surfaces  1 A and  1 C separated by a vertical element  1 B. Vertical element  1 B is shown as a low concrete wall configured to separate traffic from surfaces  1 A and  1 C. Surfaces  1 A and  1 C may be formed from standard roadway asphalt or the like. The first impact element in the form of a curb  2  is preferably a granite curb that is “pinned” to a foundation below the trafficable surface  1 . The curb  2  preferably extends approximately six (6) inches above the grade of the trafficable surface  1 , and is six (6) inches in length. The foundation is shown continuous with the confining structure  8  that contains the structure or material of bed  9 . The confining structure  8  is preferably a reinforced concrete foundation having a depth  17  that is approximately four (4) feet deep. Contained in the concrete foundation of the confining structure  8  is a deformable material preferably made from a crushable cellular concrete material having a compressive strength within a range of approximately 30-60 psi. The bed  9  preferably has dimensions of approximately 48 inches in length, 36 inches in depth, and may have any suitable width to accommodate the intended application. Above the bed  9  having the deformable material is shown the surface cover layer  7 . Surface cover layer  7  is preferably made from stone pavers or the like and has a depth of approximately three (3) inches. As shown in  FIGS. 3-6 , the top of the surface cover layer  7  is preferably at approximately the same elevation as the top of curb  2 . Beyond the bed  9  is shown the impact element line  4 . Impact element line  4  preferably comprises either a low wall formed from one or more sections extending approximately sixteen (16) inches above the top of cover layer  7 , and having a length of approximately twelve (12) inches and may have any suitable width corresponding to the width of bed  9 . Alternatively, the impact element line may formed from rows of bollards comprising steel shells containing concrete or the like and having a diameter within the range of approximately twelve (12) inches to sixteen (16) inches, and a height of approximately sixteen (16) inches above the surface layer. According to the embodiment, the bollards are configured in groups of at least two and spaced at intervals of approximately 48 inches on center. 
     According to another preferred embodiment the first impact element  2  is a granite curb that is “pinned” to a foundation below grade. The curb  2  extends approximately six (6) inches above the trafficable surface  1 , and is approximately six (6) inches in length. The foundation is preferably substantially continuous with the confining structure  8  that contains the structure or material of bed  9 . The confining structure  8  is preferably a reinforced concrete foundation that is approximately 48 inches deep. Contained in the concrete foundation  8  is the bed  9  having a deformable material preferably made from crushable cellular concrete or the like and having a compressive strength within the range of approximately 30-60 psi. The bed  9  preferably has dimensions of approximately 20 feet in length, 36 inches in depth, and variable width to accommodate the intended application. Shown above bed  9  is the surface cover layer  7  that is preferably a sedum planting or the like, such as typically used in green roof installations, etc. and having a depth of approximately two (2) inches. As shown in  FIGS. 3-6 , the top of the surface cover layer  7  is configured at approximately the same elevation as the top of curb  2 . Behind the bed  9  and cover layer  7  is the impact element line  4  that preferably includes a low wall extending approximately sixteen (16) inches above the top of the cover layer, and having a length of approximately twelve (12) inches and a width corresponding to the width of at least one of the bed, the cover layer  7 , and the foundation  8 . According to alternative embodiments, the dimensions of the curb, and the bed, and the confining structure and the impact element line may be varied to suit a particular application. 
     The impact element line  4  of the vehicle barrier system  11  may also be provided as “inertia” or “friction” type barriers that are intended to rely on their weight and friction with the surface on which they are placed to provide a desired degree of impact resistance. Such inertia type impact elements may be “preformed” concrete structures (such as commonly known as “jersey barriers”) or concrete “planters” or the like that are intended for placement at a desired location. The inertia type impact elements are advantageous for “temporary” type barrier systems, in which the impact elements may only be required for a relatively short time period, or where subgrade conditions prevent easily constructing a foundation, as in the case of shallow depth utility lines, etc. 
     According to another embodiment of the vehicle barrier system as shown in  FIGS. 9 ,  10  and  16 , a sidewalk  120  is disposed between the curb  102  and a bed system  103 . The bed system  103  comprises a composite, multi-layer arrangement of materials or structure intended to arrest the progress of a vehicle, yet permit unimpeded pedestrian traffic in a pedestrian area. For example, the bed system  103  is shown to comprise a first layer, shown as a deformable material layer  109  and a second layer, shown as a pedestrian cover surface material layer or structure  107 , substantially overlying a deformable material layer or structure  109 . The sidewalk  120  is intended for pedestrian traffic, but may support incidental vehicular traffic. Typical construction for the sidewalk  120  involved a decorative paving layer (e.g. cobble, stone, brushed concrete, soil, gravel, asphalt, etc.) over compacted earth with or without a concrete sub-base in between. The sidewalk  120  serves to provide a buffer zone between the trafficable surface  101  and the bed system  103 , so that incidental vehicular traffic adjacent to the trafficable surface  101  does not disturb the deformable structure or material layer  109  of the bed system  103 . The sidewalk  120  may be constructed to building code standards for sidewalks or terraces subject to vehicular traffic, as indicated in building codes such as the New York City Building Code or the International Building Code, where such a sidewalk would typically be required to have a Minimum Uniform Live Load capacity of 250 pounds per square foot (psf) or Minimum Concentrated Live Load requirement of 8,000 lbs. In this embodiment the curb  102  may be used, as in previous embodiments, to direct a potential threat vehicle upwards so that it descends into the bed  103 . According to a preferred embodiment, the curb has a height that extends within a range of substantially one (1) inch to ten (10) inches above the trafficable surface. Under other scenarios, the curb may not serve to direct the vehicle upwards, for example, in the case where a vehicle&#39;s speed might not be high enough or its suspension calibrated so that the vehicle&#39;s wheels do not lose contact with the trafficable surface  101 , curb  102 , or sidewalk  120 . In this scenario, the curb would serve as a visual indicator to vehicle drivers, signaling the end of the trafficable zone and the beginning of the pedestrian sidewalk  120 . 
     In related embodiments, as shown in  FIGS. 11 ,  12 ,  13 ,  14 , and  15  the curb  102  is replaced with a visual indicator element  121 . The visual indicator element  121  provides a recognizable cue to the driver of a vehicle of the delineation of the trafficable surface  101  and the pedestrian sidewalk  120 . The visual indicator element  121  is shown as generally flush (e.g. having a substantially equivalent top elevation) with both the trafficable surface  101  and the pedestrian sidewalk  120 . The visual indicator element  121  alerts drivers through a difference in appearance such as painting or markings (e.g. in pattern(s), distinctive color scheme, etc.) or having a distinct material and/or texture (e.g. stone, concrete, wood, metal, etc.) from the surrounding paving conditions of the trafficable surface  101  and the sidewalk  120 . 
     In a preferred embodiment the confining structure  108  of the bed system includes retaining walls  122  (e.g. formed from reinforced concrete, stone, sheet metal, wood, compacted soil, masonry, etc. or any suitable combination). These walls  122  serve to separate the deformable material layer  109  from the surrounding sub-grade condition (e.g. soil, sand, concrete, utility lines, etc.). In related embodiments, the walls are defined as having four (4) or more distinct sides (i.e. front  122 A, left  122 B, right  122 C, and rear  122 D). Accordingly, the rear wall  122 D is intended to bear the impact of a vehicle that has traversed the bed system  103 , broken through the pedestrian cover surface layer  107 , and deformed the deformable material layer or structure  109  (such as described in previous embodiments as being performed by the impact element line  4 ). The rear wall  122 D is designed to stop (e.g. arrest, halt, disable, etc.) a vehicle that impacts it (as described in previous embodiments). In some embodiments, such as those indicated in  FIGS. 10 ,  11 ,  12  and  15 , the top of the rear wall is shown at an elevation substantially equivalent with the top of the pedestrian cover surface layer  107 . In other embodiments, such as shown in  FIG. 13 , the height of the top elevation of the rear wall  122 D is above the top elevation of the pedestrian cover surface layer  107  (such as, but not limited to, a height within the range of approximately 0-24 inches above the pedestrian cover surface). In this embodiment, the rear wall  122 D can be equipped with an architectural cover (e.g. bench, wall, curb, etc.) of unique material (stone, metal, glass, wood, composite, polymer, etc.) in order to enhance its aesthetic appearance. In other embodiments, such as  FIG. 14 , the top elevation of the rear wall  122 D is below the top elevation of the pedestrian cover surface layer  107 . The relative elevation of the rear wall  122 D is determined by the expected elevation of a potential attacking vehicle after it has been lowered in elevation by compressing into the deformable material layer  109 . 
     According to a related embodiment as shown for example in  FIGS. 12 and 15 , a second visual indicator element  123  is disposed between the sidewalk  120  and the bed  103 . The second visual indicator element  123  is intended to provide a second cue to a vehicle that has already crossed over the first indicator element and is driving on the sidewalk  120 . The second visual indicator element  123  may be similar to the first visual indicator element  121  in that it is distinct in appearance from the sidewalk  120 , the trafficable surface  101 , and the pedestrian cover surface layer  107  (as shown to substantially overlie the deformable material layer  109 ). 
     According to a further embodiment as shown for example in  FIG. 16 , both the first indicator element  121  and the second indicator element  123  are replaced by curbs  102  and  124  respectively, curb  102  shown for example as having an equivalent top elevation with the pedestrian sidewalk, and curb  124  shown for example as having an equivalent top elevation with the top of the pedestrian cover surface  107  of the bed  103 . This “double curb” system serves to provide visual as well as an elevation change (e.g. tactile indication) to alert a driver that the vehicle has left the trafficable surface and is approaching a restricted area, and imparts a vertical velocity component on the vehicle as it enters the bed system  103 . 
     According to a further embodiment, the pedestrian cover surface layer  107  is intended to spread pedestrian loads over the deformable material layer  109  in the bed system  103 . The pedestrian cover surface layer  107  comprises a sidewalk paving material (e.g. paving elements such as masonry, bricks, stone, cobbles, pavers, etc.—which may be provided in the form of a “loose” unit paving system where the paving elements are laid loose and adjacent to one another over the deformable material) or a planting system (e.g. a material such as soil, sand, grass, sedum, bushes or other planting material, etc.) configured to support pedestrian loads, but configured to give way under vehicle loads and/or the tire motion (spinning, turning, etc.) of a vehicle that drives over the pedestrian cover layer  107  so that the tires of the vehicle breach (e.g. crush, tear, break, etc.) the pedestrian cover layer  107  and come in contact with the layer of deformable or compressible material  109  below. Once the pedestrian cover surface layer  107  is breached, the spinning motion of the vehicle&#39;s tires combined with the weight of the vehicle cause it to deform the deformable material layer  109  so that the deformable material layer  109  fails inelastically (i.e. breaks, tears, or is crushed, etc.). According to a preferred embodiment, the deformable material layer  109  comprises a structure (e.g. lattice, honeycomb, etc.) constructed of metal, polycarbonate, plastic, composite metal, wood, etc. and configured to breakaway, collapse, crush, sink or otherwise deform under the weight of the vehicle. The deformable material layer  109  may also comprise a substance (e.g. uniform or composite), alone or in combination with a structure, having characteristics that permit the material to crush, compress, yield, displace, or otherwise deform, such as, for example, cellular concrete, resin, metallic foam, synthetic foam, polymeric foam, (or other material having voids filled with air or the like) or any other suitable material of combination of such materials, having a predefined compression strength, sufficient to crush under a tire(s) of a vehicle weighing at least approximately 2,500 pounds (lbs). The vehicle&#39;s weight combined with the rotation (e.g. “spinning” etc.) of the vehicle&#39;s tires is intended to deform (e.g. collapse, crush, compress, yield, displace, etc.) the deformable material layer  109 , so that the elevation of the vehicle “drops” or is otherwise “lowered.” The deformation of the deformable material layer  109  of the bed system  103  tends to lower the effective height of the vehicle, as the elevation of the vehicle decreases (e.g. sinks, falls, etc.) into the deformable material  109 , as well as reducing the vehicle&#39;s speed, due at least in part to the friction between the tires and the compressible structure of material. 
     According to any exemplary embodiment of the present invention, the vehicle barrier system is intended to provide an installed barrier for use along a boundary or border such as a security perimeter to protect sites that may be susceptible to a vehicle born intrusion or attack. The vehicle barrier system is designed so that in can be crossed by pedestrians and the like, but prevents passage by vehicles such as automobiles. The vehicle barrier systems employs a variable “composite” approach, using a combination of different attenuation devices and methods in succession to stop a vehicle within a short distance or limited space, such as are typically encountered near buildings and the like. The vehicle barrier system is intended to provide an installed barrier having a “rating” as a crash type barrier consistent with applicable governmental rating criteria. For example, the vehicle barrier system is intended to provide a rating of at least any one of the following K ratings (i.e. a measure of the barrier&#39;s potential to stop a vehicle at escalating speed as dictated by standards determined by the U.S. Department of State: K4 (15,000 lb vehicle traveling at 30 miles per hour (mph)), K8 (15,000 lb. vehicle traveling at 40 mph), or K12 (15,000 lb. vehicle traveling at 50 mph. 
     It is also important to note that the construction and arrangement of the elements of the vehicle barrier system as shown in the preferred and other exemplary embodiments is illustrative only. Although only a few embodiments of the present inventions have been described in detail in this disclosure, those skilled in the art who review this disclosure will readily appreciate that many modifications are possible (e.g., variations in sequence, sizes, dimensions, structures, shapes, profiles and proportions of the various elements, values of parameters, mounting arrangements, use of materials, ballast, orientations, compositions of compressible materials, etc.) without materially departing from the novel teachings and advantages of the subject matter recited. For example, elements shown as integrally formed may be constructed of multiple parts or elements show as multiple parts may be integrally formed. By further way of example, the deformable zone may include a bed having any suitable structure or material configured to support the weight of pedestrians and other generally permissible loads, but is configured to deform sufficiently under the weight of a vehicle or other generally impermissible loads so that the elevation of the vehicle is lowered in relation to the surface grade and to facilitate contact of the vehicle chassis with a second impact element that may have a generally lowered elevation. It should also be noted that the system may be used in association with a wide variety of applications (e.g. corporations, government facilities, entertainment venues, private residences, hospitals, hotels, religious and cultural institutions, etc.) and that the elements of the system may be provided in any suitable size, shape, material and appearance that meets applicable design and performance standards and that creates a desired appearance corresponding to the location of the system. Accordingly, all such modifications are intended to be included within the scope of the present inventions. Other substitutions, modifications, changes and omissions may be made in the design, operating conditions and arrangement of the preferred and other exemplary embodiments without departing from the spirit of the present inventions. 
     The order or sequence of any process or method steps may be varied or re-sequenced according to alternative embodiments. Other substitutions, modifications, changes and omissions may be made in the design, operating configuration and arrangement of the preferred and other exemplary embodiments without departing from the spirit of the inventions as expressed in the appended claims.