Abstract:
A freeway cloverleaf and transit cloverleaf, and system, having preferred embodiments that offer one or more of these advantages: reduced congestion and/or “weaving” in the immediate vicinity of the intersection of the two freeway routes; means for transit vehicles—and more generally all passenger carrying vehicles—to proceed to proximate transfer locations, which may be situated above the intersection, or which may be linked by elevated walkways, such that people need move only a short distance to complete a transfer from one route to another; facilitates ride sharing, car pooling and “park-and-ride,” including but not limited to scenarios where people drive to a transit facility with parking, and can complete a trip—often commuting to work—using transit; facilitates more efficient transit vehicle use, including switching among larger or smaller transit vehicles based on projected and/or real-time consumer demand; connects people and vehicles with surrounding neighborhoods, including retail and other businesses, by means of the park-and-ride and transit features; promotes biking and the use of other “people roller” technology for short trip; reduces congestion.

Description:
BACKGROUND OF THE INVENTION 
       [0001]    The traditional cloverleaf highway intersection has been in use for decades. Most generally it is built when two freeway-speed routes intersect at roughly a 90 degree angle. In the context of countries where people drive on the right, there are four inner cloverleaf loops; typically entered by a vehicle just beyond the intersection of an intersecting freeway route. The vehicle exits one freeway route, and loops 270 degrees around the inner cloverleaf, while changing elevation as needed to conform to the intersecting freeway route that the vehicle will be entering. After turning 270 degrees, the vehicle enters the intersecting route; the effect of this is to have completed a left hand turn from a first freeway right of way on to a second freeway right of way. The traditional cloverleaf intersection also typically has four arc shaped perimeter lanes; each perimeter arc lane allows traffic from one of the intersecting freeway routes to effect what amounts to a right hand turn from a first freeway right of way on to a second freeway right of way. The combination of the four inner cloverleaf loops and the four perimeter arc lanes allows drivers on any right hand lane of the intersecting freeway routes to effect either a right hand turn or a left hand turn on to the intersecting route. 
         [0002]    The traditional cloverleaf design is significantly sub-optimal from the points of view of: safety, efficiency, transit, ride sharing, congestion, and land use. Regarding safety and efficiency, some vehicles are entering an inner cloverleaf are slowing down and merging right to exit just beyond the intersection, while other vehicles are leaving an inner cloverleaf, speeding up and merging left just before the intersection. This combination of speed and lane changes near the intersection is often called “weaving,” and creates both the danger of collisions, and a general tendency for traffic at the intersection to slow down whenever the intersection becomes congested. During rush hours, a significant slowdown at one cloverleaf intersection can cause gridlock, which can quickly spread through the freeway system. 
         [0003]    Regarding congestion, freeway cloverleafs are often part of networks of freeways and other roads that frequently become congested for various reasons; this is a chronic problem with road systems generally. 
         [0004]    Regarding transit, there is no good way for people to transfer from transit vehicles, and buses in particular, at a traditional cloverleaf intersection. Because traffic is merging immediately to either side of the cloverleaf in all directions, it is not practical for transit vehicles to stop near the intersections. However, if transit vehicles stop at any significant distance from the intersection, either means must be provided to let people move quickly from one transit stop to another, or there will be a significant time delay and inconvenience whenever people transfer. Similarly with ridesharing, car pooling and park-and-ride arrangements, it is typically impractical for people to attempt to rideshare whenever a vehicle entry or exit is necessary at a freeway cloverleaf. Finally, the traditional cloverleaf intersection requires a significant amount of land, which is typically not put to any utilitarian use. In addition to the amount of space occupied, the situation of a cloverleaf will tend to disrupt local street grids, and traffic, which must be routed around the cloverleaf footprint. 
         [0005]    An additional net overall result of the widespread use of traditional freeway cloverleaf designs is communities that become almost entirely dependent on cars, because the presence of a cloverleaf greatly increases walking distances from one address to another among the commercial and retail development that is typically built on the land surrounding a cloverleaf. 
       BRIEF DESCRIPTION OF THE INVENTION 
       [0006]    The present invention comprises a Transit Cloverleaf, having preferred embodiments that offer one or more of these advantages: reduced congestion and/or “weaving” in the immediate vicinity of the intersection of the two freeway routes; allows transit vehicles—and more generally all passenger carrying vehicles—to proceed to proximate transfer locations, which may be situated above the intersection, or which may be linked by elevated walkways, such that people need move only a short distance to complete a transfer; facilitates ride sharing, car pooling and “park-and-ride,” where people drive to a transit facility with parking, and can complete a trip—often commuting to work—using transit; facilitates more efficient transit vehicle use, including switching among larger or smaller transit vehicles based on projected and/or real-time consumer demand; connects people and vehicles with surrounding neighborhoods, including retail and other businesses, by means of the park-and-ride and transit features; promotes biking and the use of other “people roller” technology for short trip; reduces congestion. 
         [0007]    The present invention further comprises a series of embodiments, including an inexpensive, “basic embodiment,” having upgrade paths such that existing traditional freeway cloverleafs can be converted first to a less expensive Transit Cloverleaf of the present invention having more limited functionality, and can then be upgraded, in one or more stages, to other preferred embodiments that are more expensive, but that have more functionality and features. 
         [0008]    Regarding safety and efficiency, some preferred embodiments of the present invention eliminate the four 270 degree inner cloverleafs of the traditional freeway cloverleaf design. Vehicles exit the freeways they are on at the same location as with the current inner cloverleaf: just beyond the intersection. However, instead of then circling 270 degrees to the right, they are routed on an elevated left turn lane that curves off to the left, passes over the freeway they just exited, and then merges with the outer arc lane on the other side of the freeway. The result is the same as for the traditional inner cloverleaf: a left hand turn on to the intersecting freeway has been effected. Advantages follow, including but not limited to these: First, because the perimeter arc lanes have a much wider radius, good lines of sight, and less traffic, it is safer and more efficient to merge left turning traffic at about the midpoint of these lanes, rather than just before the intersection of the two freeway routes. Second, because one merging entrance is eliminated, all merging onto freeways now occurs only at one point along each freeway route—from the perimeter arc lanes. This happens well beyond the intersection, and affords room to add longer merging lanes. Because the perimeter arc lanes have a much wider radius than the inner cloverleafs, vehicles can also reach or maintain freeway speed well before merging onto the freeway. The result is both improved safety and efficiency. Because freeway traffic will not tend to change speed when congestion occurs, the system of the present invention is more efficient, moving more traffic at a uniform, higher speed, while avoiding slowdowns that can quickly escalate to congestion backing up for miles. 
         [0009]    Regarding transit—and more generally entrances and exits from one vehicle to another—it is effectively impossible to do this with the current cloverleaf design. At the intersection of the freeway routes, traffic is both entering and exiting each freeway right lane. There is no place near the intersection where a bus or any passenger carrying vehicle can safely stop. Even if buses and other vehicles could safely stop well before or well after the intersection—and this is problematic—the distance from one stopping point to another would typically require a long walk, possibly up to 500 feet or more. People are not inclined to want to walk such a long distance to a transfer point, especially when having things to carry. 
         [0010]    Some embodiments of the present invention move passenger carrying vehicles to a central traffic area situated above the intersection of the freeways. Passengers enter and exit vehicles at elevated and/or at-grade vehicle transfer points. Because the transfer area is typically not large, typically dimensioned a maximum of about twice the width of all freeway right of way lanes, or less, people do not have far to walk when transferring from one vehicle to another. 
         [0011]    Regarding ridesharing, car pooling, and “park-and-ride,” and connections with surrounding neighborhoods, much of the land area within the four perimeter arc lanes of the present invention can be paved and marked for “park-and-ride” use. Embodiments of the present invention may comprise an elevated park-and-ride “overleaf” structure that is contiguous with a central, elevated traffic area. Each overleaf may further comprise an elevated “park-and-ride” lot, used by cars and private passenger vehicles both for dropping off and picking up passengers from the traffic area, and for short term Park-and-Ride use—such as shopping, other errands, and appointments. An entrance ramp rises from the lower and larger at-grade park-and-ride lots to a park-and-ride overleaf. Vehicles exiting the overleaf descend the same ramps used for merging on to the perimeter arc lanes, but instead branch to the left at the bottom of the ramp, entering the lower and larger at-grade park-and-ride lots. Embodiments of the present invention may further comprise perimeter tunnels, or perimeter tunnel intersections, installed at one, some or all of the four perimeter arc lanes, also allowing traffic, and people either walking or using wheeled means, including bikes, to move to and from adjacent neighborhoods and at-grade surface park-and-ride areas. 
         [0012]    Regarding the more efficient use of transit vehicles, embodiments of the present invention may further comprises a garage, used to shelter and/or maintain a range of sizes and configurations of transit vehicles. People may be made available at the garage and tasked with moving vehicles back and forth between the garage and the nearest Park-and-Ride overleaf, and/or responding to projected and/or real time demand for transit service. In this way, the use of larger, more expensive vehicles can be limited to times when there is enough demand to require or justify their greater capacity for passengers. 
         [0013]    Additional drivers can be on call, available to drive additional transit vehicles, including smaller vehicles stationed at the garage, as an alternative response to surges in demand. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0014]      FIG. 1  is a top view of a traditional cloverleaf intersection. 
           [0015]      FIG. 1   a  is the top view of  FIG. 1 , showing a pair of inner cloverleaf ramps, and intersecting freeways. 
           [0016]      FIG. 1   b  is the top view of  FIG. 1 , showing the pair of inner cloverleaf ramps, and intersecting freeways. 
           [0017]      FIG. 1   c  is the top view of  FIG. 1 , showing all four inner cloverleaf ramps, both intersecting freeways, and further illustrating all lane crossing when merging. 
           [0018]      FIG. 1   d  is the top view of  FIG. 1 , further illustrating extended perimeter arc merging lanes. 
           [0019]      FIG. 1   e  is the top view of  FIG. 1 , further illustrating non-transfer zone perimeters. 
           [0020]      FIG. 1   f  is a top view of inner cloverleafs, and inner cloverleaf-freeway merging lanes. 
           [0021]      FIG. 1   g  is the top view of  FIG. 1 , further illustrating vehicle transfer lanes. 
           [0022]      FIG. 1   i  is the top view of  FIG. 1 , further illustrating inner transfer points. 
           [0023]      FIG. 1   j   1   a  is a top view of a perimeter tunnel intersection. 
           [0024]      FIG. 1   j   1   b  is a top view of a perimeter tunnel intersection. 
           [0025]      FIG. 1   j   1   c  illustrates perimeter tunnel intersection elevations. 
           [0026]      FIG. 1   j   1   d  illustrates perimeter tunnel intersection elevations. 
           [0027]      FIG. 1   j   1   e  illustrates perimeter tunnel intersection lanes and sidewalks. 
           [0028]      FIG. 1   k  is a top view of a cloverleaf intersection. 
           [0029]      FIG. 1   k   1  is the top view of  FIG. 1   k , further illustrating an elevated pedestrian central transfer structure. 
           [0030]      FIG. 1   l  is a top view of a cloverleaf intersection. 
           [0031]      FIG. 1   l   1  is the top view of  FIG. 1   l , further illustrating an elevated pedestrian central transfer structure. 
           [0032]      FIG. 1   l   2  is the top view of  FIG. 1   l , further illustrating perimeter tunnel intersections. 
           [0033]      FIG. 1   l   3  is the top view of  FIG. 1   l   2 , further illustrating up and over lanes, before an upgrade process. 
           [0034]      FIG. 1   l   4  is the top view of  FIG. 1   l   3 , after an upgrade process. 
           [0035]      FIG. 1   l   5  is an illustration of a cloverleaf intersection, illustrating the relationship of an upgrade stage to a preferred embodiment. 
           [0036]      FIG. 1   l   5   a  is the top view of  FIG. 1   l   5 , further illustrating an elevated pedestrian central transfer structure. 
           [0037]      FIG. 1   l   6  is a top view of a cloverleaf intersection. 
           [0038]      FIG. 1   l   6   a  is the top view of  FIG. 1   l   6 , further illustrating freeway exits. 
           [0039]      FIG. 1   l   6   b  is the top view of  FIG. 1   l   6 , omitting illustration of some elements, and further illustrating freeway exits. 
           [0040]      FIG. 1   l   7  is a top view of a cloverleaf intersection, further illustrating an elevated park-and-ride area. 
           [0041]      FIG. 1   l   8  is a top view of a cloverleaf intersection, further illustrating an elevated central transfer area. 
           [0042]      FIG. 2  is the top view of  FIG. 1   a , also illustrating an up and over ramp replacing one of the pair of inner clover leaf ramps. 
           [0043]      FIG. 2   a  is a wider top view of  FIG. 2 , illustrating up-and-over ramps for all quadrants, each replacing one inner clover leaf ramp, and also illustrating all lane crossing when merging. 
           [0044]      FIG. 3  is the top view of  FIG. 2 , also illustrating elevated central transfer ramps. 
           [0045]      FIG. 3   a  is a wider top view of  FIG. 3 , illustrating elevated central transfer ramps for all quadrants. 
           [0046]      FIG. 4  is the top view of  FIG. 3 , further illustrating an elevated central transfer structure. 
           [0047]      FIG. 4   a  is a wider top view of  FIG. 4 , further illustrating an elevated park-and-ride area and a vehicle garage. 
           [0048]      FIG. 4   c  is a top view of elements of  FIG. 4   a , further illustrating perimeter tunnel intersections. 
           [0049]      FIG. 4   c   1  is the top view of  FIG. 4   c , further illustrating elevated thru lanes. 
           [0050]      FIG. 4   c   1   a  is the top view of  FIG. 4   c   1 , omitting elements illustrated in phantom. 
           [0051]      FIG. 4   c   1   a   1  is the top view of  FIG. 4   c   1   a , omitting some elevated thru lane elements 
           [0052]      FIG. 4   c   1   a   2  is the top view of  FIG. 4   c   1   a , omitting some elevated thru lane elements. 
           [0053]      FIG. 5  is an elevated perspective view of elements of  FIG. 4 . 
           [0054]      FIG. 5   a  is an elevated perspective view of elements of  FIG. 4   a.    
           [0055]      FIG. 5   b  is an elevated perspective view of elements of  FIG. 4   c   1   a.    
       
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
       [0056]    In this specification the phrases freeway cloverleaf intersection and freeway cloverleaf are used interchangeably. While a freeway cloverleaf typically comprises four quadrants, it may more generally comprise a plurality of quadrants.  FIG. 1  shows a top view of a traditional freeway cloverleaf intersection,  100 , comprising a first freeway right of way,  108 , and an intersecting grade separated second freeway right of way,  109 ; this intersection in turn forms four freeway quadrants,  101 . It will be understood that although illustrations of embodiments of the present invention are typically drawn symmetrically, that renderings of both traditional cloverleafs, and of embodiments of the present invention, will sometimes comprise freeway intersections that do not intersect at right angles, and will further comprise other elements that correspond in their function to the elements described in this patent, but that are not dimensionally symmetric. It will be further understood that all elements of the present invention presented as present for one freeway quadrant, may be present for a plurality of freeway quadrants. 
         [0057]    The first freeway right of way,  108 , of the traditional cloverleaf intersection of  FIG. 1  further comprises a graded and centrally elevated right of way,  104 , further comprising a lower elevation,  105 , at each end, rising to an upper elevation,  106 , contiguous with an elevated central plateau area,  107 , having a lower side elevated above the second freeway right of way,  109 , such that there is sufficient clearance for vehicles driving on the second freeway right of way,  109 , to pass beneath the graded and centrally elevated plateau area,  107 , of the first freeway right of way,  108 . 
         [0058]    Each direction of the first freeway right of way,  108 , and the second freeway right of way,  109 , of the traditional cloverleaf,  100 , of  FIG. 1  further comprises a right outer freeway lane,  102 , and typically also one or more inner thru freeway lanes,  103 . 
         [0059]    Each of the quadrants,  101 , of the traditional cloverleaf intersection,  100 , of  FIG. 1  comprises an inner cloverleaf,  120 . Each inner cloverleaf,  120 , further comprises an inner cloverleaf entrance from freeway,  122 , contiguous with an inner cloverleaf-freeway merging lane,  121 , and an inner cloverleaf exit to freeway,  123 , also contiguous with an inner cloverleaf-freeway merging lane,  121 . 
         [0060]    Vehicles using a traditional cloverleaf intersection effect a left turn from one freeway right of way to the intersecting freeway right of way by merging from a right outer freeway lane,  102 , on to an inner cloverleaf-freeway merging lane,  121 , then using an inner cloverleaf entrance from freeway,  122 , completing a turn of approximately 270 degrees on the inner cloverleaf,  120 , then using an inner cloverleaf exit to freeway,  123 , to enter an inner cloverleaf-freeway merging, lane,  121 , and then merging to a right outer freeway lane,  102 . 
         [0061]    Referring now to  FIG. 1   f , the system of inner cloverleafs,  120 , and inner cloverleaf-freeway merging lanes,  121 , is more generally a means for vehicles to effect something that cannot be done at a typical traffic signal regulated intersection—multiple, or cascading, left hand turns. As a practical matter, this allows vehicles to turn around at a cloverleaf, and continue in the direction they were coming from. To illustrate the options for a complete 360 degree circuit, a vehicle can begin proceeding East to West on a right outer freeway lane,  102 , merge on to an inner cloverleaf-freeway lane,  121 , loop around the East-West to North-South inner cloverleaf,  149 , and enter an inner cloverleaf-freeway lane  121 . The vehicle can then either merge on to the right outer freeway lane,  102 , and proceed North to South, or it can enter the North-South to West-East inner cloverleaf,  150 , and enter an inner cloverleaf-freeway lane,  121 . The vehicle can then either merge on to the right outer freeway lane,  102 , and proceed West to East, turning around in effect from its original direction, or it can enter the West-East to South-North inner cloverleaf,  151 , and enter an inner cloverleaf-freeway lane,  121 . The vehicle can then either merge on to the right outer freeway lane,  102 , and proceed South to North, or it can enter the South-North to East-West inner cloverleaf,  152 , and enter an inner cloverleaf-freeway lane,  121 . If the vehicle then merges on to the right outer freeway lane,  102 , it will again be proceeding East to West; the direction that it started from. Thus, a cloverleaf intersection,  110 , allows vehicles to effect a left turn without stopping, and to allow for freeway systems with a continuous flow of traffic, without interruptions from stop signs or stop lights. 
         [0062]    Referring now to  FIG. 1 , each of the quadrants,  101 , of the traditional cloverleaf,  100 , comprises a perimeter arc lane,  181 , further comprising a perimeter arc entrance from freeway,  182 , intersecting a right outer freeway lane,  102 , and a perimeter arc exit to freeway,  183 , also intersecting a right outer freeway lane,  102 . Vehicles using a traditional cloverleaf intersection can effect a right turn from one freeway right of way to the intersecting freeway right of way by using perimeter arc entrance from freeway,  182 , completing a turn of approximately 90 degrees on the perimeter arc lane,  181 , and then using a perimeter arc exit to freeway,  183 . 
         [0063]    Referring now to  FIG. 1   e , from the point of view of transit, and more generally for people who want to enter or exit a vehicle, or change vehicles at or near a cloverleaf intersection,  110 , there is a serious problem with the system of inner cloverleafs,  120 , and inner cloverleaf-freeway merging lanes,  121 , of the traditional freeway cloverleaf,  100 . Referring now to  FIG. 1   g , alternative embodiments of the present invention can comprise for one, some, or all quadrants,  101 , an additional inner cloverleaf vehicle transfer lane,  153 , to the right of each inner cloverleaf-freeway merging lane,  121 , each inner cloverleaf-freeway merging lane further comprising a first vehicle transfer lane inner cloverleaf intersection,  154 , and a second vehicle transfer lane inner cloverleaf intersection,  155 . 
         [0064]    However, absent such additional inner cloverleaf vehicle transfer lanes,  153 , or other means for effecting transfers near the cloverleaf intersection,  110 , including preferred embodiments to be detailed later in this specification, referring now to  FIG. 1   e , the use of the inner cloverleaf-freeway merging lanes,  121 , has the effect of establishing an inner non-transfer zone perimeter,  111 ; within this perimeter it is not possible for a bus, or more generally any vehicle, to pull to the side of a freeway right of way,  108  or  109 , using a lane approximately parallel to a right outer freeway lane,  102 , to allow passengers to enter and/or exit a vehicle. The minimum distance required to stop, or to reach the speed of vehicles on the inner cloverleaf-freeway merging lanes,  121 , has the further effect of establishing an outer non-transfer zone perimeter,  112 ; outside of this perimeter it is possible for buses and other vehicles to stop and allow people to enter and exit the vehicle. 
         [0065]    For vehicles wishing to both change direction at a cloverleaf intersection,  110 , and to have passengers enter or exit the vehicle, a transfer point before the intersection, such as the transfer point before intersection,  114 , may be used. Vehicles may then either proceed in the same direction, or may effect one or more left turns, by proceeding to enter an inner cloverleaf,  120 ; a right turn may be effected by entering the perimeter arc lane,  181 , in the same quadrant,  101 . 
         [0066]    Similarly, a transfer point beyond the intersection, such as a transfer point beyond intersection,  113 , may be used. Vehicles may then either proceed in the same direction by entering the perimeter arc lane,  181 , in the same quadrant,  101 ; or may effect one or more left turns, (including three left turns of 270 degrees, the equivalent of one 90 degree right turn,) by entering an inner cloverleaf,  120 . 
         [0067]    While a system of bus and vehicle transfer points can be effected for a traditional cloverleaf,  100 , by having vehicles pull over at a transfer point before intersection,  113 , or a transfer point beyond intersection,  114 , additional difficulties remain, including the distance people and their possessions must move between transfer points, and of course the need to cross one or more freeway right of ways,  108  or  109 , to reach another transfer point. 
         [0068]    Referring now to  FIG. 1   i , if we remove the constraint of using a lane approximately parallel to a right outer freeway lane,  102 , to allow passengers to enter and exit the vehicle, one preferred embodiment of the present invention, to be detailed later in the specification, comprises an inner cloverleaf inner vehicle transfer lane,  161 , used to reach an inner cloverleaf inner transfer point,  162 . 
         [0069]    Regarding additional design problems and constraints of the traditional cloverleaf,  FIG. 1   a  shows a top view of two inner cloverleafs,  120 , of a traditional freeway cloverleaf,  100 . For the first freeway right of way,  108 , both right outer freeway lanes,  102 , and inner thru freeway lanes,  103 , are illustrated; for the second freeway right of way,  109 , only the right outer freeway lanes,  102 , are illustrated.  FIG. 1   a  further illustrates dashed inner cloverleaf entrance merging trend lines,  126 ; illustrating that as some vehicles proceed to the inner cloverleaf entrance from freeway,  122 , of the inner cloverleafs,  120 , they may change lanes from one of the inner thru freeway lanes,  103 , to a right outer freeway lane,  102 , while decelerating to the lower speed required for the inner cloverleaf,  120 .  FIG. 1   a  further illustrates dashed inner cloverleaf exit merging trend lines,  127 ; illustrating that as some vehicles proceed from the inner cloverleaf exit to freeway,  123 , of the inner cloverleafs,  120 , they may change lanes from one of the right outer freeway lanes,  102 , to an inner thru freeway lane,  103 , while accelerating to the higher speed required for an inner thru freeway lane,  103 . 
         [0070]    Based on the above explanation, the traditional freeway cloverleaf,  100 , has serious design problems.  FIG. 1   b , focuses only on vehicles entering or exiting inner cloverleafs,  120 , as they proceed East to West, using the directional convention of maps, on the first freeway right of way,  108 . One set of vehicles tends to move along the inner cloverleaf entrance merging trend line,  126 , both decelerating and changing lanes to the right. The paths of this first set of vehicles tend to conflict with the paths of a second set of vehicles which in turn tend to move along the inner cloverleaf exit merging trend line,  127 , that is accelerating and changing lanes to the right. This problem is commonly referred to as “weaving.” With respect to East-West traffic on the first freeway right of way,  108 , the inner cloverleaf entrance merging trend line,  126 , and the inner cloverleaf exit merging trend line,  127 , of  FIG. 1   b  can be grouped as paired east-west inner merging trend lines,  131 . In short, at the vicinity of the cloverleaf intersection,  110 , we find two sets of vehicles that are tending to “weave”—changing both speed and direction in opposition to each other. Further, the path of any one of these vehicles can change suddenly and unpredictably. The number of vehicles entering or exiting the inner cloverleafs,  120 , is also unpredictable; an inner cloverleaf,  120 , can change very quickly from a state of having no vehicles, to a state of congestion. The fact that some drivers may be drunk, or otherwise chemically impaired, is a further danger and difficulty. 
         [0071]    One consequence of the design problems inherent in the traditional freeway cloverleaf,  100 , of the  FIG. 1  series is a danger of collisions, caused either directly by vehicles entering or exiting an inner cloverleaf,  120 , or caused by other vehicles maneuvering in response. A second consequence is a general tendency to reduce the number of cars flowing through the cloverleaf intersection,  110 , as caution prompts vehicles to slow down when approaching and when passing through the intersection. A third consequence is a tendency for congestion to occur at the cloverleaf intersection,  110 —as vehicles slow down, heavy traffic behind them may then be forced to slow down or stop. This congestion can quickly spread back from the cloverleaf intersection,  100 , for long distances along the freeway rights of way,  108 , and  109 , and can take a long time to clear. 
         [0072]      FIG. 1   c  illustrates paired merging trend lines for each direction of each freeway right of way of the traditional freeway cloverleaf,  100 , together with entering and exiting merging trend lines for each perimeter arc lane,  181 . The paired East-West inner merging trend lines,  131 , have already been considered in detail above. The East-West perimeter arc exit merging trend line,  141 , illustrates that some North-South traffic leaving the second freeway right of way,  109 , merges with East-West traffic on the first freeway right of way,  108 , by crossing lanes from right to left. Because such merging occurs well beyond the cloverleaf intersection,  110 , the disruption to East-West traffic on the first freeway right of way,  108 , is not as serious a problem, and danger to safety, as the disruption caused by traffic tending to follow the dashed inner cloverleaf exit merging trend line,  127 . Similarly, the East-West perimeter arc entrance merging trend line,  142 , allows East-West traffic to leave the first freeway right of way,  108 , and merge with South-North traffic on the second freeway right of way,  109 , again well beyond the cloverleaf intersection,  110 . There is minimal associated disruption and danger to safety as traffic tends to follow the East-West perimeter arc entrance trend line,  142 . 
         [0073]      FIG. 1   c  illustrates that for each direction of traffic on each of the two freeway right of ways, the processes, and associated problems and safety dangers described with respect to East-West traffic on the first freeway right of way,  108 , are also present. Specifically, with respect to the paired East-West inner merging trend lines,  131 , the East-West perimeter arc exit merging trend line,  141 , and the East-West perimeter arc entrance trend line,  142 ; for west-east traffic there is respective correspondence with the paired West-East inner merging trend lines,  132 , the West-East perimeter arc exit merging trend line,  143 , and the West-East perimeter arc entrance trend line,  144 ; for North-South traffic there is respective correspondence with the paired North-South inner merging trend lines,  133 , the North-South perimeter arc exit merging trend line,  145 , and the North-South perimeter arc entrance trend line,  146 ; for South-North traffic there is respective correspondence with the paired South-North inner merging trend lines,  134 , the South-North perimeter arc exit merging trend line,  147 , and the South-North perimeter arc entrance trend line,  148 . 
         [0074]    Referring now to  FIG. 1   d , it should be noted that it may often be possible to provide a perimeter arc extended exit-merging lane,  185 , allowing traffic exiting a perimeter arc lane,  181 , to have more time and distance to merge smoothly onto a right outer freeway lane,  102 , mitigating the disruption and danger to safety described above. Similarly, a perimeter arc entrance extended merging lane,  184 , can allow traffic entering a perimeter arc lane,  181 , more time and distance to complete the exit smoothly and safely. Extended merging lanes can be enhancements of a traditional cloverleaf,  100 , or can be comprised in embodiments of the present invention. 
       First Preferred Embodiment of the Present Invention 
       [0075]    Referring now to  FIG. 2 , a first preferred embodiment of the present invention comprises an up and over lane,  201 , which allows vehicles to effect a left hand turn from a first freeway right of way,  108 , to an intersecting second freeway right of way,  109 , in this respect duplicating the function of an inner cloverleaf,  120 , rendered in phantom in  FIG. 2 , of the freeway cloverleaf,  100 . Referring now to  FIG. 5 , the up and over lane,  201 , is rendered in perspective, crossing above a first freeway right of way,  108 . Referring now to  FIG. 2 , as a specific example, vehicles proceeding East to West on a first freeway right of way,  108 , enter the up and over lane,  201 , at an inner quadrant entrance from freeway,  124 , which is typically contiguous with an inner cloverleaf-freeway merging lane,  121 . However, rather than following the rightward curving path of the traditional inner cloverleaf,  120 , rendered in phantom, vehicles proceed on an overleaf lane leftward curving ramp section,  202 , which goes up and over the first freeway right of way,  108 , and merges with a perimeter arc lane,  181 , at an inner quadrant exit to freeway,  125 . 
         [0076]      FIG. 2   a  illustrates an up and over lane,  201 , for all four quadrants,  101 , of the freeway cloverleaf,  100 . The inner cloverleaf-freeway merging lanes,  121 , are no longer contiguous with, now referring to  FIG. 1 , an inner cloverleaf exit to freeway,  123 . Referring now to  FIG. 2   a , the inner cloverleaf-freeway merging lanes,  121 , can therefore be extended to as far as the intersection of a perimeter arc lane,  181 , near a perimeter arc entrance,  182 , or beyond. Two advantages follow from such an extension. First, both safety and smooth traffic flow are enhanced when vehicles have more time and distance to merge from a right outer freeway lane,  102 , onto an inner cloverleaf-freeway merging lane,  121 . Second, if there is a traffic jam, for example on one direction of a first freeway right of way,  108  an inner cloverleaf-freeway merging lane,  121 , from a second freeway right of way,  109 , leading to the contiguous up and over lane,  201 , that merges in to the traffic jam can function as a queue for traffic heading from the second freeway right of way,  109 , into the traffic jam. Thus, a longer inner cloverleaf-freeway merging lane can help to prevent a traffic jam on one direction on a first freeway right of way,  108 , from spreading to a direction on the intersecting second freeway right of way,  109 . However, there is a danger that if drivers decide they don&#39;t want to wait in a long queue, they may attempt to merge back into traffic on a right outer freeway lane,  102 , where traffic is typically moving at freeway speed. This would create a serious safety hazard; traffic merging on to a right outer freeway lane,  102 , from an inner cloverleaf-freeway merging lane,  121 , defeats one major purpose of having an up and over lane,  201 . Extended merging, entrance and exit lanes, including barriers to prevent vehicles from merging back into traffic on a lane they have recently exited, such as a right outer freeway lane,  102 , will be examined after preferred embodiments of the present invention are introduced. 
         [0077]      FIG. 3  illustrates an elevated central transfer ramp,  301 , that is contiguous with an up and over lane,  201 . Referring now to  FIG. 5 , the elevated central transfer ramp,  301 , leads to an elevated central transfer structure,  321 , and to a transfer square transfer point,  322 , where people can get in and out of buses and/or other passenger vehicles. Referring now to  FIG. 3 , as an example of the use of the elevated central transfer ramp,  301 , a vehicle proceeding East to West on the first freeway right of way,  108 , can proceed along the right outer freeway lane,  102 , to an inner quadrant entrance from freeway,  124 , then to the elevated central transfer ramp entrance,  302 , and then up the elevated central transfer ramp entrance section,  303 , to the transfer square transfer point,  322 , where people can enter and/or exit the vehicle. The vehicle can then continue down the elevated central transfer ramp exit section,  305 , to the elevated central transfer ramp exit,  304 , merge on to the perimeter arc lane,  181 , and then to the right outer freeway lane,  102 , continuing East to West on the first freeway right of way,  108 . 
         [0078]      FIG. 3   a  illustrates an elevated central transfer ramp,  301 , for all four quadrants,  101 , of the freeway cloverleaf,  100 . By varying the direction—East to West or West to East, for the first freeway right of way,  108 , and North to South or South to North, for the second freeway right of way,  109 —the example of the previous paragraph can be extended to demonstrate a vehicle can start from any direction on a freeway right of way,  108  or  109 , proceed to a transfer square transfer point,  322 , and continue on the same freeway right of way,  108  or  109 , proceeding in the original direction. Thus, buses and other passenger carrying vehicles can bring people to four elevated transfer square transfer points,  322 , that are within easy walking distance of one another. 
         [0079]      FIG. 4  illustrates elevated central transfer ramps,  301 , for all four quadrants,  101 , of the freeway cloverleaf,  100 , together with an elevated central transfer structure,  321 , linking transfer square transfer points,  322 , for all four quadrants,  101 . Referring now to  FIG. 5 , the elevated central transfer structure,  321 , further comprises four covered walkways,  323 , each covered walkway being contiguous with a transfer square transfer point,  322 , at each end, and each covered walkway,  323 , comprising an outer curb,  324 , that is parallel to a central transfer structure perimeter vehicle right of way,  325 . Referring now to  FIG. 4 , people can exit a bus, or more generally a vehicle, at a transfer square transfer point,  322 , and can then use one or more covered walkways,  323 , to proceed to any other transfer square transfer point,  322 , or an outer curb,  324 , where they can enter another bus, or more generally a vehicle. Thus, transfers can be effected for buses that are traveling in any direction on a freeway right of way,  108  or  109 , and continuing in the same direction. Buses, and more generally vehicles, can also proceed from any elevated central transfer ramp entrance,  302 , up the elevated central transfer ramp entrance section,  303 , to a transfer square transfer point,  322 , or an outer curb,  324 , and can then proceed clockwise along one or more central transfer structure perimeter vehicle right of ways,  325 , to any elevated central transfer ramp exit section,  305 . A bus, or more generally any vehicle, can then continue in any direction on a freeway right of way,  108  or  109 , by merging from an elevated central transfer ramp exit,  304 , on to a perimeter arc lane,  181 , and then merging from a perimeter arc exit,  183 , onto a right outer freeway lane,  102 . 
         [0080]    Continuing to refer to  FIG. 4 , as a convenience for passengers, buses may complete a circuit around the perimeter of the elevated central transfer structure,  321 , stopping at any transfer square transfer point,  322 , where people may want to enter or exit, and then proceeding down the elevated central transfer ramp exit,  305 , of the elevated central transfer ramp,  301 , that they entered, stopping at that transfer square transfer point,  322 , first and last, or last, on their circuit. 
         [0081]    Continuing to refer to  FIG. 4 , it will be understood that the elevated central transfer structure,  321 , is specifically designed to facilitate park and ride, car pooling, ride sharing, localized vehicle rentals and local taxi service, and biking, as well as transfers from one bus to another. The transfer square transfer points,  322 , will typically be reserved for use by buses, to minimize transfer time. All other vehicles will use the central transfer structure perimeter vehicle right of ways,  325 , to pull up to an outer curb,  324 , contiguous with a covered walkway,  323 , and to effect transfers of people and their possessions to and from vehicles. Referring now to  FIG. 5 , at-grade Park-and-Ride areas,  115 , comprise much or most of the area of each quadrant,  101 . Referring now to  FIG. 4 , the first preferred embodiment of the present invention comprises park and ride elevators,  326 , illustrated as rectangles in each corner, and linking at grade park and ride areas,  115 , to transfer square transfer points,  322 , of the elevated central transfer structure,  321 . Although not rendered in the drawings, it will be understood that the elevated central transfer structure,  321 , may be dimensioned such that Park-and-Ride elevators,  326 , move only vertically, from an at-grade base that is set back a substantial distance from the right outer freeway lanes,  102 , of the freeway right of ways,  108  and  109 , to an upper landing that is between a transfer square transfer point,  322 , and the center of the elevated central transfer structure,  321 . As a second alternative, the elevated central transfer structure,  321 , may be dimensioned such that park and ride elevators,  326 , move both vertically and horizontally, from an at-grade base that is set back a substantial distance from the right outer freeway lanes,  102 , of the freeway right of ways,  108  and  109 , to an upper landing that is nearer to the center of the elevated central transfer structure,  321 , and between a transfer square transfer point,  322 , and the center of the elevated central transfer structure,  321 . As a third alternative, the elevated central transfer structure,  321 , may be dimensioned such that Park-and-Ride elevators,  326 , move only vertically, from an at-grade base that is set back a substantial distance from the right outer freeway lanes,  102 , of the freeway right of ways,  108  and  109 , to an upper landing that is further from the center of the elevated central transfer structure,  321 , than a transfer square transfer point,  322 . This alternative will be examined later in this specification. 
         [0082]    Referring now to  FIG. 4   a , the first preferred embodiment of the present invention comprises perimeter arc lane tunnels,  186 , for each quadrant,  101 , of the freeway cloverleaf,  100 . A variant of the first preferred embodiment further comprises freeway right of way tunnels,  116 , connecting each quadrant,  101 , to the two contiguous and adjacent quadrants of the freeway cloverleaf,  100 . To the extent that vehicles and people are able to use the elevated central transfer structure,  321 , or an elevated feature comparable in function, to move from one quadrant,  101 , to another quadrant, freeway right of way tunnels,  116 , may be unnecessary or not cost justifiable. Referring now to the perspective illustration of  FIG. 5   a , one perimeter arc lane tunnel,  186 , and one freeway right of way tunnel,  116 , are illustrated. 
         [0083]    Referring now to  FIG. 4   a , in general, perimeter arc lane tunnels,  186 , and/or freeway right of way tunnels,  116 , facilitate the movement of vehicles and people both within the confines of the freeway cloverleaf,  100 , and also between the freeway cloverleaf and surrounding neighborhoods comprising businesses and residences. The connections with neighborhoods provided by the perimeter arc lane tunnels,  186 , significantly improve the ability of people to include park and ride, car pooling, ride sharing, localized vehicle rentals and local taxi service, and biking, as elements meeting their transit needs. 
         [0084]    Referring now to  FIG. 4   a , the first preferred embodiment of the present invention further comprises one or more elevated park and ride ramps,  341 , and may further comprise one or more elevated park and ride areas,  351 . Referring now to  FIG. 5   a , one elevated park and ride area,  351 , is illustrated, and is contiguous with an elevated park and ride ramp,  341 ; a second, stand alone elevated park and ride ramp,  341 , is also illustrated. Referring now to  FIG. 4   a , vehicles can proceed from an at-grade Park-and-Ride area,  115 , to the elevated central transfer structure,  321 , by proceeding to an elevated park and ride at grade entrance,  342 , and then up the elevated park and ride ramp,  341 , merging on to an elevated central transfer ramp entrance section,  303 , and then proceeding to the elevated central transfer structure,  321 . Vehicles can then proceed clockwise around the elevated central transfer structure,  321 , by traversing one or more central transfer structure perimeter vehicle right of ways,  325 ; passengers and their possession can transfer to and from vehicles at any outer curb,  324 , as described earlier. Vehicles can exit the elevated central transfer structure,  321 , by proceeding down any elevated central transfer ramp exit section,  305 . On reaching an elevated central transfer ramp exit,  304 , vehicles can then either proceed on to a freeway right of way,  108  or  109 , by merging on to a perimeter arc lane,  181 , and then merging on to a right outer freeway lane,  102 , or they can proceed to an elevated Park-and-Ride at-grade exit,  343 , and can then either use the at-grade Park-and-Ride parking area,  115 , or can proceed to a perimeter arc lane tunnel,  186 . 
         [0085]    Referring now to  FIG. 5   a , because an elevated Park-and-Ride area,  351 , is both proximate to and at the same level as the elevated central transfer structure,  321 , this is a premium parking area. Vehicles at grade can enter the elevated Park-and-Ride area,  351 , from an elevated Park-and-Ride area entrance from elevated central transfer ramp,  352 . Vehicles traversing the perimeter of the elevated central transfer structure,  321 , can enter the elevated Park-and-Ride area,  351 , from an elevated Park-and-Ride area entrance from elevated central transfer structure,  354 . Vehicles can exit the elevated Park-and-Ride area,  351 , to a perimeter arc lane,  181 , or to at-grade Park-and-Ride areas,  115 , by means of an elevated Park-and-Ride area exit to elevated central transfer ramp,  353 . Vehicles can traverse the perimeter of the elevated central transfer structure,  321 , from an elevated Park-and-Ride area exit to the elevated central transfer structure,  355 . Based on these conveniences, preference can be given for local Park-and-Ride rental vehicles, available for people who want to shop or go to a business in the neighborhood of the freeway cloverleaf,  100 . Preference can also be given for Park-and-Ride users who are not commuters, but want to Park-and-Ride for a shorter time, such as two hours or less, while using transit to go to one or more other locations and back. 
         [0086]    Referring now to  FIG. 4   c , the first preferred embodiment of the present invention can comprise an alternative elevated central transfer area,  390 , functioning in the same manner, and for the same purposes, now referring to  FIG. 4 , as the elevated central square transfer square,  321 . Referring now to  FIG. 4   c , the elevated central transfer area,  390 , further comprises central transfer area bus transfer points,  392 , within the central transfer inner area,  391 . The elevated central transfer area,  390 , can be dimensioned such that the central transfer area bus transfer points,  392 , are close together, making it easier for people, and anything they are bring with them, to transfer between buses. The elevated central transfer area inner perimeter lane,  393 , can be restricted to busses, which can enter from any elevated central transfer ramp,  301 , proceed clockwise around the elevated central transfer area inner perimeter lane,  393 , effect transfers at one or more central transfer area bus transfer points,  392 , and exit to any elevated central transfer ramp,  301 . The elevated central transfer area,  390 , further comprises an elevated central transfer area outer pedestrian boulevard,  394 , having at its perimeter a central transfer area outer curb,  395 , that is contiguous with an elevated central transfer area outer perimeter lane,  396 . Vehicles can enter the elevated central transfer area outer perimeter lane,  396 , from any elevated central transfer ramp,  301 , proceed clockwise around it, effect transfers at one or more points around the central transfer area outer curb,  395 , and exit to any elevated central transfer ramp,  301 . Park and ride elevators,  326 , can also be added, connected to the elevated central transfer ramp,  301 , by park and ride elevator walkways,  397 . 
         [0087]    As illustrated in  FIG. 4   c , the alternative first preferred embodiment can comprise both the elevated central transfer ramp,  301 , and an elevated park and ride area,  351 , functioning in the same manner, and for the same purposes, as described earlier in this specification when referencing  FIG. 4   a  and  FIG. 5   a.    
       Second Preferred and Upgradable Embodiment of the Present Invention 
       [0088]      FIG. 1   k  illustrates a second preferred and upgradable embodiment of the present invention, comprising four up and over lanes,  201 , which function as detailed in in the first preferred embodiment, allowing vehicles to effect a left hand turn from one to the other of the freeway right of ways,  108  and  109 , in this respect, now referring to  FIG. 2 , duplicating the function of an inner cloverleaf,  120 , rendered in phantom, of the traditional freeway cloverleaf,  100 . Referring again to  FIG. 1   k , the second preferred embodiment further comprises an inner cloverleaf,  120 , for each of the four quadrants,  101 , of the freeway cloverleaf,  100 . However, because the cloverleafs are no longer needed to effect a left turn from one freeway right of way to another—this function being assumed by the up and over lanes,  201 —referring now to  FIG. 1 , the inner cloverleaf-freeway merging lanes,  121 , referring now to  FIG. 1   k , are separated from the right outer freeway lanes,  102 , with intersection spanning lane change barriers,  163 , and are repurposed as inner cloverleaf left turn and linking lanes,  164 . To use the inner cloverleaf system of the second preferred embodiment of the present invention, vehicles merge from a right outer freeway lane,  102 , onto an inner cloverleaf left turn and linking lane,  164 , at an inner cloverleaf left turn and linking lane entrance,  165 . Vehicles can then either proceed to an up and over lane,  201 , effecting a left turn on to the intersecting freeway right of way, or vehicles can proceed to the inner cloverleaf,  120 . All vehicles can proceed around an inner cloverleaf,  120 , branch left at an inner cloverleaf fork,  167 , and can then proceed to an adjacent inner cloverleaf, effecting any number of left hand turns, as described earlier in this specification with reference to  FIG. 1   f . Transit users can loop around the inner cloverleaf,  120 , and branch right at an inner cloverleaf fork,  167 . Buses can then stop at an inner cloverleaf bus transfer point,  166 , where passengers can enter and exit. All other vehicles can pull up to an inner cloverleaf transfer curb,  168 , where passengers can enter and exit. 
         [0089]    Referring now to  FIG. 1   k   1 , people can proceed, with their possessions, including bicycles, to and from an inner cloverleaf bus transfer point,  166 , or an inner cloverleaf transfer curb,  168 , or an at grade park and ride area,  115 , to a transfer elevator,  170 , which connects with an elevated pedestrian central transfer structure,  356 . Elevator specifications should be such as to accommodate a surge of both people and their possessions, including bicycles, and to move people fast enough to provide an excellent level of customer service. People can then proceed to another corner of the elevated pedestrian central transfer structure,  356 , go down in a transfer elevator,  170 , and proceed to an inner cloverleaf bus transfer point,  166 , or an inner cloverleaf transfer curb,  168 , or an at grade park and ride area,  115 . In this way, people can effect a transfer from one bus to another, or more generally can transfer to and from any combination of vehicles. Although  FIG. 1   k   1  illustrates two transfer elevators,  170 , for each quadrant,  101 , it is understood that in some situations only one elevator may be installed at each quadrant. It should be noted that in the event of an elevator malfunction, vehicles can proceed to another inner cloverleaf,  120 , and people can transfer from there—one or more cabs can also be dispatched to the cloverleaf to shuttle people to other quadrants with working transfer elevators,  170 . For this reason, embodiments of the present invention need not necessarily comprise redundant multiple transfer elevators,  170 , for each quadrant  101 . 
         [0090]    Referring now to  FIG. 1   k , once people have transferred to and from vehicles at an inner cloverleaf bus transfer point,  166 , or an inner cloverleaf transfer curb,  168 , the vehicles may continue along the inner cloverleaf left turn and linking lane,  164 , to enter an up and over lane,  201 . As a second alternative, vehicles may exit the inner cloverleaf,  120 , at an inner cloverleaf inner exit point,  169 , enter a perimeter tunnel intersection,  401 , at a perimeter tunnel intersection inner entrance,  402 , or, for buses, an optional, dedicated, perimeter tunnel intersection inner bus entrance,  435 , pass under the inner cloverleaf,  120 , make a left turn within the perimeter tunnel intersection,  401 , exit the perimeter tunnel intersection at a perimeter tunnel intersection merging exit,  403 , merge onto a perimeter arc inner merging lane,  187 , then merge on to a perimeter arc lane,  181 , and finally merge on to a right outer freeway lane,  102 . If a vehicle has entered only one inner clover leaf,  120 , the vehicle will be proceeding in the same direction as when it first entered the inner clover leaf. As a third alternative, vehicles may park on at-grade park and ride areas,  115 , either inside the inner cloverleaf, or outside of it, but within a perimeter arc lane,  181 , of a quadrant,  101 , using a perimeter tunnel intersection,  401 , to access these areas. As a fourth alternative, vehicles may exit the freeway cloverleaf,  100 , through a perimeter tunnel intersection,  401 , proceeding to surrounding neighborhoods. 
         [0091]    Vehicles, pedestrians and bikers may all enter the freeway cloverleaf,  100 , through any of the perimeter tunnel intersections,  401 , of the second preferred embodiment of the present invention. 
         [0092]    Continuing to refer to  FIG. 1   k , a perimeter tunnel intersection phantom circle area,  404 , highlights a section of the freeway cloverleaf,  100 , comprising a perimeter tunnel intersection,  401 . Referring now to  FIG. 1   j   1   b , this perimeter tunnel intersection phantom circle area,  404 , is rotated such that the perimeter tunnel intersection right of ways,  407 , are horizontal or vertical. The perimeter tunnel intersection,  401 , comprises a lane crossing right of way,  405 , that passes below a perimeter arc lane,  181 , and an inner cloverleaf,  120 , and further comprises a perpendicular perimeter arc tangential right of way,  406 , that is approximately tangential to a perimeter arc lane,  181 , a perimeter arc inner merging lane,  187 , an up and over lane exit merging lane,  203 , and an inner cloverleaf,  120 . 
         [0093]    Referring now to  FIG. 1   j   1   a , the horizontal lane crossing right of way,  405 , is shown aligned in cross section to a lane crossing right of way elevation contour,  408 , having lane crossing right of way at grade elevations,  409 , at each side, sloping down to a lane crossing right of way below grade central elevation,  410 . Similarly, the vertical perimeter arc tangential right of way,  406 , is shown aligned in cross section to a perimeter arc tangential right of way elevation contour,  411 , having perimeter arc tangential right of way at grade elevations,  412 , at each side, sloping down to a perimeter arc tangential right of way below grade central elevation,  413 . Thus, the lane crossing right of way,  405 , viewed from above, comprises a rectangular lane crossing right of way below grade central area,  414 . 
         [0094]    Continuing to refer to  FIG. 1   j   1   a , a perimeter arc lane,  181 , a perimeter arc inner merging lane,  187 , an up and over lane exit merging lane,  203 , and an inner cloverleaf,  120 , are shown as tangentially and approximately parallel to a perimeter arc lanes elevation contour,  415 , having perimeter arc lanes at grade elevations,  416 , at each side representing the elevation of the surface of the lanes, and sloping up to a perimeter arc lanes above grade central under side elevation,  417 , representing not the surface but the under side of the elevated lanes, and to a perimeter arc lanes above grade central surface elevation,  418 . 
         [0095]    Referring now to  FIG. 1   j   1   c , a perimeter arc tangential right of way elevation contour,  411 , and a perimeter arc lanes elevation contour,  415 , are rendered as contiguous along a common at grade elevation,  436 . The distance between the lane crossing right of way below grade central elevation,  410 , and the perimeter arc lanes above grade central under side elevation,  417 , is sufficient to allow vehicles proceeding, now referring to  FIG. 1   j   1   b , on a perimeter tunnel intersection right of way,  407 , to pass under a perimeter arc lane,  181 , a perimeter arc inner merging lane,  187 , an up and over lane exit merging lane,  203 , and an inner cloverleaf,  120 . 
         [0096]    Referring now to  FIG. 1   j   1   d , two first dashed extension lines,  419 , extend the two sides of the perimeter arc lanes above grade central under side elevation,  417 , to lanes that exist at the time a conversion of an existing freeway cloverleaf into a second preferred embodiment of the present invention: the perimeter arc lane,  181 , and an inner cloverleaf,  120 . Because a perimeter arc inner merging lane,  187 , and an up and over lane exit merging lane,  203 , are elements of the second preferred embodiment of the present invention, these elements are rendered with dashed lines. To minimize disruption and inconvenience for users of a freeway cloverleaf during the conversion process, modules are installed to elevate the perimeter arc lanes,  181 , and the inner cloverleafs,  120 , as required. The following process is repeated for each quadrant of a freeway cloverleaf. First, cuts are made in the perimeter arc lanes,  181 , and the inner cloverleafs,  120 , along the first dashed extension lines,  419 ; and suspension structures are installed on the sides of the cut out lane sections, such that a perimeter arc lane removal section,  422 , and an inner cloverleaf removal section,  423 , are ready to be removed quickly by crane. Preformed modules are positioned at the site, ready to be installed quickly by crane. A first installation process can be completed during an interval of a few hours at night, comprising these steps: first, a perimeter arc lane removal section,  422 , is removed by crane; second, an elevated perimeter arc lane central module,  424 , is installed by crane; third, an elevated perimeter arc lane first outer module,  425 , is installed by crane, and secured to the elevated perimeter arc lane central module,  424 ; fourth, an elevated perimeter arc lane second outer module,  426 , is installed by crane, and secured to the elevated perimeter arc lane central module,  424 . A second installation can also be completed during an interval of a few hours at night, comprising these steps: first an inner cloverleaf removal section,  423 , is removed by crane; second an elevated inner cloverleaf central module,  427 , is installed by crane, third, an elevated inner cloverleaf first outer module,  428 , is installed by crane, and secured to the elevated inner cloverleaf central module,  427 , fourth, an elevated inner cloverleaf second outer module,  429 , is installed by crane, and secured to the elevated inner cloverleaf central module,  427 . Following these procedures, additional elements of the second preferred embodiment of the present invention can be constructed and/or installed with minimal disruption to the continuing operation of the freeway cloverleaf. Although only one perimeter arc lane is illustrated, it is understood that some existing freeway cloverleafs may have two lanes, to allow either for multi-rider vehicles to pass other vehicles in a queue, and/or to allow for greater queue capacity; modifications to the installation procedure, including the use of additional elevated modules, can be made accordingly. 
         [0097]    Referring now to  FIG. 1   j   1   e , the lane crossing right of way,  405 , of the perimeter tunnel intersection,  401 , of the present invention further comprises two dedicated right lanes,  430 , allowing a continuous flow or queuing of traffic in both directions, and a reversible direction and queuing center lane,  431 , the traffic direction and use being controlled by a light signaling system. Initially, the reversible direction and queuing center lane may not be used, or, alternatively, the most typical use of the reversible direction and queuing center lane,  431 , may be for queuing; accordingly, only the right lane extensions,  433 , are shown as bringing traffic into and out of the lane crossing right of way,  405 . The lane crossing right of way,  405 , further comprises a sidewalk,  432 , for pedestrians, including wheelchair users. The perimeter arc tangential right of way,  406 , comprises only one lane, with a reversible direction controlled by a light signaling system. One lane is sufficient due to the short distance end to end, anticipated low traffic volume, and anticipated width constrictions in many instances; two right lane forking extensions,  434 , are shown at either end, again managed by a light signaling system. The perimeter arc tangential right of way,  406 , further comprises a sidewalk,  432 , for pedestrians, including wheelchair users. It should be noted that due to relatively low speeds within the perimeter tunnel intersection,  401 , bikers can use either the sidewalk or the vehicle lanes. 
       Third Preferred and Upgradable Embodiment of the Present Invention 
       [0098]    The third preferred and upgradable embodiment of the present invention is the most limited of the four preferred embodiments, but is also the least expensive, and may be adequate, either on a stand alone basis, or as part of a phased upgrade towards a variant fourth preferred embodiment, and/or towards the second and/or first preferred embodiments. It is specifically designed to accommodate only transit service transfers, drop offs, and pick ups, and to a limited degree park and ride. 
         [0099]      FIG. 1   l  illustrates core elements of the third preferred embodiment, comprising: a freeway cloverleaf intersection,  100 , further comprising quadrants,  101 , further comprising a first freeway right of way,  108 , intersecting a grade separated second freeway right of way,  109 , further comprising for one or a plurality of quadrants: an inner cloverleaf,  120 , an inner cloverleaf inner vehicle transfer lane,  161 , an inner cloverleaf bus transfer point,  166 , an inner cloverleaf inner entrance point,  172 , an inner cloverleaf inner vehicle transfer lane exit point,  174 , an inner cloverleaf at grade crossing,  171 , a perimeter arc inner merging lane,  187 , and one or a plurality of transfer elevators,  170 ;  FIG. 1   l   1  illustrates an additional core element of the third preferred embodiment, an elevated pedestrian central transfer structure,  356 . 
         [0100]    Referring now to  FIG. 1   l , the third preferred embodiment of the present invention comprises one inner cloverleaf,  120 , for each quadrant,  101 , of the freeway cloverleaf,  100 . The outer perimeter lanes,  173 , of the inner cloverleafs,  120 , continue to function in combination with the inner cloverleaf-freeway merging lanes,  121 , as for a freeway cloverleaf,  100 . The third preferred embodiment further comprises an inner cloverleaf inner vehicle transfer lane,  161 , within and contiguous with each inner cloverleaf outer perimeter lane,  173 . 
         [0101]    Continuing to refer to  FIG. 1   l , buses and other vehicles can transfer passengers and continue in the same direction by entering an inner clover leaf as they would do to effect a left turn, merging from a right outer freeway lane,  102 , to an inner cloverleaf-freeway merging lane,  121 , then proceeding around the inner cloverleaf,  120 , merging from an inner cloverleaf outer perimeter lane,  173 , on to an inner cloverleaf inner vehicle transfer lane,  161 , and proceeding to an inner cloverleaf fork,  167 , beyond which the inner cloverleaf outer perimeter lane,  173 , and the inner cloverleaf inner vehicle transfer lane,  161 , are separated by an inner cloverleaf lane change barrier,  178 . Branching right at the inner cloverleaf fork,  167 , buses can then proceed to an inner cloverleaf bus transfer point,  166 ; other vehicles can proceed to an inner cloverleaf transfer curb,  168 . All vehicles can then continue in the same direction on a freeway right of way,  108  or  109 , by proceeding to the inner cloverleaf inner vehicle transfer lane exit point,  174 , then proceeding on a paved, marked path within the inner cloverleaf,  120 , crossing the inner cloverleaf at an inner cloverleaf at grade crossing,  171 , then proceeding to the nearest perimeter arc inner merging lane,  187 , merging onto a perimeter arc lane,  181 , and then merging on to a right outer freeway lane,  102 . 
         [0102]    Vehicles can use one of the inner cloverleafs,  120 , to transfer passengers and effect a left turn from one to another of the freeway right of ways,  108  and  109 , by first transferring passengers at an inner cloverleaf bus transfer point,  166 , or an inner cloverleaf transfer curb,  168 , then reentering the inner cloverleaf inner vehicle transfer lane,  161 , at an inner cloverleaf inner entrance point,  172 , merging onto an inner cloverleaf outer perimeter lane,  173 , branching to the left at the inner cloverleaf fork,  167 , and merging from the inner cloverleaf-freeway merging lane,  121 , to the right outer freeway lane,  102 . 
         [0103]    Vehicles can transfer passengers and effect a right turn from one to another of the freeway right of ways,  108  and  109 , by entering a perimeter arc lane,  181 , exiting immediately at a perimeter arc lane inner exit,  189 , then entering the inner cloverleaf at an inner cloverleaf at grade crossing,  171 , merging on to the inner cloverleaf inner vehicle transfer lane,  161 , from an inner cloverleaf inner entrance point,  172 , branching to the right at the inner cloverleaf fork,  167 , proceeding to an inner cloverleaf bus transfer point,  166 , or an inner cloverleaf transfer curb,  168 , transferring passengers to and/or from the vehicle, proceeding to the inner cloverleaf inner vehicle transfer lane exit point,  174 , then proceeding on a paved, marked path within the inner cloverleaf,  120 , crossing and exiting the inner cloverleaf at an inner cloverleaf at grade crossing,  171 , then proceeding to a perimeter arc inner merging lane,  187 , on the same perimeter arc they exited from, merging onto the perimeter arc lane,  181 , and then merging on to a right outer freeway lane,  102 . 
         [0104]    Transit transfers have been specified earlier for the second preferred embodiment with reference to  FIG. 1   k   1 ; the third preferred embodiment functions in a similar manner. Referring now to  FIG. 1   l   1 , people can proceed, with their possessions, including bicycles, to and from an inner cloverleaf bus transfer point,  166 , or an inner cloverleaf transfer curb,  168 , or an at grade park and ride area,  115 , to a transfer elevator,  170 , which connects with an elevated pedestrian central transfer structure,  356 . People can then proceed to another corner of the elevated pedestrian central transfer structure,  356 , go down in a transfer elevator,  170 , and proceed to an inner cloverleaf bus transfer point,  166 , or an inner cloverleaf transfer curb,  168 , or an at grade park and ride area,  115 . In this way, people can effect a transfer from one bus to another, or more generally can transfer to and from any combination of vehicles, including bikes as a vehicle. Although  FIG. 1   l   1  illustrates two transfer elevators,  170 , for each quadrant,  101 , it is understood that in some situations only one elevator may be installed at each quadrant. It should be noted that in the event of an elevator malfunction, vehicles can proceed to another inner cloverleaf,  120 , and people can transfer from there—one or more cabs can also be dispatched to the cloverleaf to shuttle people to other quadrants with working transfer elevators,  170 , for this reason, embodiments of the present invention need not necessarily comprise redundant multiple transfer elevators,  170 , for each quadrant  101 . 
         [0105]    Referring now to  FIG. 1   l , it should be noted that there is a significant deficiency with the third preferred embodiment not present with the first two: it does not eliminate “weaving”—more specifically, it does not eliminated traffic merging from an inner cloverleaf-freeway merging lane,  121 , to a right outer freeway lane,  102 , and the associated problems discussed earlier commencing with reference to  FIG. 1   b.    
       Upgrade of the Third Preferred Embodiment to a Variant Fourth Preferred Embodiment 
       [0106]    The present invention comprises upgradability from the third preferred embodiment to a variant fourth preferred embodiment, and/or further upgradability to the second and/or first preferred embodiment. To upgrade the third preferred embodiment to the variant fourth preferred embodiment, referring now to  FIG. 1   l   2 , perimeter tunnel intersections,  401 , comprised in the second preferred embodiment, are installed in the manner previously described with reference to  FIG. 1   j   1   a ,  FIG. 1   j   1   b ,  FIG. 1   j   1   c , and  FIG. 1   j   1   d . The perimeter tunnel intersections function in the same manner as described for the second preferred embodiment. Referring now to  FIG. 1   l , the inner cloverleaf at grade crossings,  171 , are eliminated, now referring now to  FIG. 1   l   2 , having been made redundant by the perimeter tunnel intersections,  401 . 
         [0107]      FIG. 1   l   2  illustrates core elements of the fourth embodiment, comprising: a freeway cloverleaf intersection,  100 , further comprising quadrants,  101 , further comprising a first freeway right of way,  108 , intersecting a grade separated second freeway right of way,  109 , further comprising for one or a plurality of quadrants: an inner cloverleaf,  120 , an inner cloverleaf inner vehicle transfer lane,  161 , an inner cloverleaf bus transfer point,  166 , an inner cloverleaf inner entrance point,  172 , an inner cloverleaf inner vehicle transfer lane exit point,  174 , a perimeter tunnel intersection,  401 , one or a plurality of transfer elevators,  170 , an inner cloverleaf inner perimeter traffic barrier,  175 , and an inner cloverleaf inner bus entrance,  176 ;  FIG. 1   l   1  illustrates an additional core element of the baseline embodiment, an elevated pedestrian central transfer structure,  356 . 
         [0108]    One purpose of upgrading from the third preferred embodiment to the variant fourth preferred embodiment of the present invention is to add functionality for new and/or improved links with surrounding neighborhoods, comprising car pooling, ride sharing, park and ride, and accommodating pedestrians and bikers. However, now referring to  FIG. 1   k , because the up and over lanes,  201 , comprised by both the first and second preferred embodiment, are not comprised in the variant fourth preferred embodiment, referring now to  FIG. 1   l   2 , based on both safety and traffic flow considerations detailed earlier in this specification, it is important to be able to regulate the flow of traffic entering the inner cloverleaf outer perimeter lanes,  173 , from any entrance other than an inner cloverleaf-freeway merging lane,  121 , as vehicles may branch left at the inner cloverleaf fork,  167 , proceeding to enter the inner cloverleaf-freeway merging lanes,  121 , and merging onto a right outer freeway lane,  102 . 
         [0109]    Accordingly, referring now to  FIG. 1   l   2 , the inner cloverleafs,  120 , of the fourth preferred embodiment further comprise an inner cloverleaf inner perimeter traffic barrier,  175 , that prevents vehicles inside the barrier from merging on to the inner cloverleaf inner vehicle transfer lane,  161 , except at regulated entrances, comprising a signaled inner cloverleaf inner entrance point,  172 , and an inner cloverleaf inner bus entrance,  176 . The signaled inner cloverleaf inner entrance point,  172 , may further comprise a monitoring system designed to determine present and/or projected short term future traffic flow at one or more points within and/or near the freeway cloverleaf,  100 , and programmed to allow vehicles to enter when it is determined there is sufficient capacity for additional vehicles entering to subsequently merge onto a right outer freeway lane, but not allowing vehicles to enter when data and projected traffic flow indicates a capacity constraint. Vehicles may queue up at the signaled inner cloverleaf inner entrance point,  172 , and may leave the queue and exit the inner cloverleaf,  201  via a perimeter tunnel intersection,  401 , at any time, due to on-going heavy traffic congestion. The monitoring system may display information to vehicles in queue whenever a significant delay is anticipated. 
       Full Upgrade of the Third Preferred Embodiment to the Second Preferred Embodiment 
       [0110]    The present invention further comprises upgradability from the third preferred embodiment to the second and/or first preferred embodiment. For both upgrade paths, upgrading from the third preferred embodiment to the variant fourth preferred embodiment, as discussed above, can be the first step. 
         [0111]      FIG. 1   l   3  shows the configuration of a freeway cloverleaf,  100 , of the present invention, just prior to the switch over from the variant fourth preferred embodiment to the second preferred embodiment. For each quadrant,  101 , up and over lanes,  201 , and inner cloverleaf left turn and linking lanes,  164 , are installed; however the up and over lane entrances,  204 , and the inner cloverleaf left turn and linking lane entrances,  165 , are blocked until the switch over is carried out. Intersection spanning lane change barriers,  163 , are installed, separating the right outer freeway lanes,  102 , from the inner cloverleaf left turn and linking lanes,  164 , however, the inner cloverleaf left turn and linking lanes,  164 , and the intersection spanning lane change barriers,  163 , are initially only extended to their junction,  177 , with the inner cloverleaf outer perimeter lanes,  173 . 
         [0112]      FIG. 1   l   4  shows the configuration of a freeway cloverleaf,  100 , of the present invention, just after the switch over from the variant fourth preferred embodiment to the second preferred embodiment. The freeway cloverleaf,  100 , can continue to function as the variant fourth preferred embodiment until the time of the switch over; it will be possible to complete the switch over within a few hours, for example, during low use of the freeway cloverleaf at night. Much of the switch over will be simply remarking portions of existing lanes. Referring now to  FIG. 1   l   3 , the inner cloverleaf lane change barriers,  178 , are removed, the inner cloverleaf inner perimeter traffic barriers,  175 , are removed, and the inner cloverleaf-freeway merging lanes,  121 , referring now to  FIG. 1   l   4 , are converted to inner cloverleaf left turn and linking lanes,  164 , and are extended to be contiguous with the up and over lane entrances,  204 . The intersection spanning lane change barriers,  163 , are also extended beyond the up and over lane entrances,  204 , and separate the inner cloverleaf left turn and linking lanes,  164 , and the right outer freeway lanes,  102 . After the switch over, once a vehicle has entered an inner cloverleaf,  120 , it can only reenter a freeway right of way,  108  or  109 , via a perimeter arc lane,  181 —note that using an up and over lane,  201 , is an intermediate stage in doing so. Referring now to  FIG. 1   l   3 , the need for a monitoring system associated with the signaled inner cloverleaf inner entrance point,  172 , comprised in the variant fourth preferred embodiment, may no longer be needed, and might be shut down. 
         [0113]      FIG. 1   l   5  illustrates core elements of a baseline embodiment, comprising: a freeway cloverleaf intersection,  100 , further comprising quadrants,  101 , further comprising a first freeway right of way,  108 , intersecting a grade separated second freeway right of way,  109 , further comprising for one or a plurality of quadrants: an inner cloverleaf,  120 , an inner cloverleaf inner vehicle transfer lane,  161 , an inner cloverleaf bus transfer point,  166 , an inner cloverleaf inner entrance point,  172 , an inner cloverleaf inner vehicle transfer lane exit point,  174 , an inner cloverleaf at grade crossing,  171 , and a perimeter arc inner merging lane,  187 , or, alternatively, a perimeter tunnel intersection,  401 , one or a plurality of transfer elevators,  170 , an up and over lane,  201 , an up and over lane entrance,  204 , an up and over lane exit merging lane,  203 , and intersection spanning lane change barrier,  163 ;  FIG. 1   l   1  illustrates an additional core element of the baseline embodiment, an elevated pedestrian central transfer structure,  356 . 
         [0114]    Referring now to  FIG. 1   l   5 , this is a consolidation of both  FIG. 1   k  and  FIG. 1   l   4 , also illustrating the inner cloverleaf at grade crossings,  171 , of  FIG. 1   l   1 , and illustrates that from a functional point of view the conversion of the third and/or variant fourth preferred embodiment to the first preferred embodiment can be brought to an intermediate stage that it is identical to the second preferred embodiment—this will be termed the second preferred embodiment baseline, which may or may not include inner cloverleaf at grade crossings,  171 ; this can be observed by a comparison of  FIG. 1   l   5  with  FIG. 1   k —or to a modified version of the third preferred embodiment further comprising the up and over lanes,  201 , of the second preferred embodiment. Referring now to  FIG. 1   l   4 , most or all of the area inside each inner cloverleaf,  120 , can be paved, or may already have been paved, such that it is available for park and ride parking; this paving can be, or can be made, contiguous with the entire inner perimeter of the inner cloverleaf inner vehicle transfer lane,  161 , which can now be entered and exited at multiple points, indicated by surfacing markings, and without the need for signaling to control entrance and exit. Accordingly, the inner cloverleaf inner bus entrances,  176 , now referring to  FIG. 1   l   5 , are no longer needed, and are omitted. 
         [0115]      FIG. 1   l   5   a  is identical to  FIG. 1   l   5 , except for the additional illustration of the elevated pedestrian central transfer structure,  356 . 
       Upgrade of the Second Preferred Embodiment Baseline to the First Preferred Embodiment 
       [0116]    Referring to  FIG. 1   l   5 , this upgrade procedure applies to the second preferred embodiment baseline with or without the presence of inner cloverleaf at grade crossings,  171 ; it should be noted that inner cloverleaf at grade crossings,  171 , and perimeter tunnel intersections,  401 , are typically mutually exclusive. Referring now to  FIG. 1   l   5   a , the first step in upgrading from the second preferred embodiment baseline to the first preferred embodiment, is to raise the elevated pedestrian central transfer structure,  356 , including the upper landings of the transfer elevators,  170 , such that they can continue to function while the structure of the first preferred embodiment is built around and beneath it. When the first preferred embodiment is complete, the modules of the elevated pedestrian central transfer structure can be disassembled and removed, however the transfer elevators,  170 , can be left in place, now referring to  FIG. 1   l   6 , with their upper landings adjusted to the level of transfer elevator ramps,  179 , installed around them, and linking them to the first preferred embodiment elevated central transfer structure,  321 , such that the transfer elevators,  170 , can continue to function as elements of the first preferred embodiment. 
         [0117]      FIG. 1   l   6  renders with thinner, phantom lines the lanes illustrated in  FIG. 1   l   5  that are inside the perimeter arc inner merging lanes,  187 , and the perimeter arc lanes,  181 , but outside the right outer freeway lanes,  102 , of the freeway right of ways,  108  and  109 , and, now referring again to  FIG. 1   l   6 , illustrates in thicker, solid lines, elevated central transfer ramps,  301 , elevated park and ride ramps,  341 , and the elevated central transfer structure,  321 , comprised by the first preferred embodiment of the present invention. The freeway cloverleaf,  100 , can continue to operate as the second preferred embodiment until the time of the switch over. Dimensioning of the elevated central transfer structure,  321 , can be such that the transfer elevators,  170 , of the second preferred embodiment can be well clear of the perimeter of the elevated central transfer structure,  321 . Each elevated central transfer ramp,  301 , can comprise an elevated central transfer ramp modular entrance section,  380 , and an elevated central transfer ramp modular exit section,  381 , which can be installed at the time of switch over, thus allowing construction of the upgrade to the first preferred embodiment to proceed without disrupting the use of the second preferred embodiment. 
         [0118]    The switch over can be accomplished by closing the freeway cloverleaf,  100 , for a few hours, typically late and night and into the early morning, and is carried out as follows: the elevated central transfer ramps,  301 , are linked at each end to the up and over lanes,  201 , the elevated park and ride ramps,  341 , are opened, and the upper landings of the transfer elevators,  170 , are adjusted as described above. 
         [0119]      FIG. 1   l   6   a  illustrates core elements of a first preferred embodiment, comprising: a freeway cloverleaf intersection,  100 , further comprising quadrants,  101 , further comprising a first freeway right of way,  108 , intersecting a grade separated second freeway right of way,  109 , further comprising for one or a plurality of quadrants: transfer elevator ramps,  179 , transfer elevators,  170 , an inner cloverleaf bus transfer point,  166 , an up and over lane,  201 , an up and over lane entrance,  204 , an up and over lane exit merging lane,  203 , a central transfer structure perimeter vehicle right of way,  325 , an elevated pedestrian central transfer structure,  356 , an inner cloverleaf left turn and linking lane,  164 , an inner cloverleaf left turn and linking lane entrance,  165 , an elevated central transfer ramp,  301 , an elevated central transfer ramp entrance,  302 , an elevated central transfer ramp entrance section,  303 , an elevated central transfer ramp exit,  304 , and an elevated central transfer ramp exit section,  305 . 
         [0120]    Referring now to  FIG. 1   l   7 , as a second alternative, the upgrade of a freeway cloverleaf,  100 , from the second preferred embodiment to the first preferred embodiment can further comprise one or more elevated park and ride areas,  351 , functioning in the same manner, and for the same purposes, as described earlier in this specification when referencing  FIG. 4   a  and  FIG. 5   a.    
         [0121]    Referring now to  FIG. 1   l   8 , as a third alternative, the upgrade from the second to the first preferred embodiment of the present invention can further comprise an elevated central transfer area,  390 , functioning in the same manner, and for the same purposes, as described earlier in this specification when referencing  FIG. 4   c.    
       Additional Functionality from Extended Merging Lanes and Queuing 
       [0122]    Congestion can be a major problem with any road system. As discussed earlier, referring to  FIG. 1 , congestion can quickly spread from an inner cloverleaf,  120 , to one or more right outer freeway lanes,  102 , resulting in gridlock that can quickly spread to freeway right of ways,  108  and/or  109 . 
         [0123]    Preferred embodiments of the present invention that effect left turns using, now referring to  FIG. 2   a , up and over lanes,  201 , may effect a significant improvement in reducing the spread of congestion by eliminating weaving near the cloverleaf intersection,  110 . Referring to  FIG. 1   k , better links with surrounding neighborhoods by means of perimeter tunnel intersections,  401 , can also allow significant volumes of traffic to quickly and voluntarily divert from any given cloverleaf intersection. It is anticipated that communication technology generally, comprising elements cited in this specification, will be used in combination with the present invention to inform and encourage drivers and/or automated driving systems to respond to current and/or anticipated congestion conditions by exiting freeways and using the surrounding road infrastructure. 
         [0124]    It is anticipated three specific elements of freeway lane design will be impacted by the present invention. First, some freeways have, or are planned to have, at-grade lanes that are either dedicated to buses, or to some combination of multi-passenger vehicles and may further include vehicles with only a driver, who are willing to pay a toll, which may vary in price according to current or anticipated congestion conditions. The intention is to keep traffic flowing on these lanes even if other lanes, including adjacent lanes, are slowing down or stopped due to congestion. In addition, at-grade right lanes and/or shoulders are sometimes reserved for buses. 
         [0125]    One major purpose of these lane restrictions is to ensure that the effect of congestion on transit vehicles is mitigated or eliminated. 
         [0126]    Generally speaking, the present invention is not intended to advance the approach of preferring the operation at or below capacity of any particular at-grade lane in preference to other at-grade lanes, other than, now referring to  FIG. 1   d , perimeter arc entrance extended merging lanes,  184 , and perimeter arc extended exit-merging lanes,  185 , which may be extended indefinitely. Although the present invention can be used in combination with various systems for collecting additional revenue based on a combination of freeway use and number of passengers, the particular emphasis of the present invention is on both reducing the use of private single passenger vehicles, and more generally on rendering a transportation system that has sufficient capacity to maintain continuous use of all lanes at the speed limits they are designed to accommodate. At-grade lane designs and configurations may contribute significantly to purposes of the present invention, including embodiments comprising the following enumerated potential elements. 
         [0127]    Referring now to  FIG. 1   l   6   a , preferred embodiments of the present invention may further comprise restricted transit freeway exits,  370 , reserved for only transit vehicles, such as buses. A preferred embodiment of the present invention having restricted transit freeway exits,  370 , together with signal regulation of the elevated park and ride at grade entrances,  342 , the elevated central transfer ramp entrances,  302 , and the up and over lane entrances,  204 , can be operated such that transit vehicles are preferred, so they will not be delayed by congestion within the freeway cloverleaf,  100 . Transit vehicles can merge from a right outer freeway lane,  102 , to a restricted transit freeway exit,  370 , and then, given preference by signal regulation, can proceed immediately, following the quadrant entrance quadrant entrance first dashed line routes,  371 , to an elevated park and ride at grade entrance,  342 . Because the signaling system is regulating the volume of traffic entering the elevated central transfer ramp entrances,  302 , the flow of traffic around the central transfer structure perimeter vehicle right of way,  325 , and the rate at which vehicles exit the central transfer structure perimeter vehicle right of way,  325 , to one of the elevated central transfer ramp exit sections,  305 , can both be regulated, ensuring there will be a very low probability of any congestion as the transit vehicle proceeds. Transit vehicles can exit the central transfer structure perimeter vehicle right of way,  325 , to any elevated central transfer ramp exit section,  305 , merge on to a perimeter arc inner merging lane,  187 , then merge on to a perimeter arc lane,  181 , and then either continue along a perimeter arc extended exit-merging lane,  185 , or merge on to a right outer freeway lane,  102 . 
         [0128]      FIG. 1   l   6   b  is rendered to highlight merging to and from the freeway right of ways,  108  and  109 , and is derived from  FIG. 1   l   6   a , but, referring now to  FIG. 1   l   6   a , does not illustrate the elevated central transfer structure,  321 , or the transfer elevator ramps,  179 , and illustrates only sections of the up and over lanes,  201 , and the elevated central transfer ramps,  301 , that interface with the restricted transit freeway exits,  370 , and the perimeter arc inner merging lanes,  187 . As discussed earlier with reference to  FIG. 1   k , because inner cloverleafs,  120 , are not needed to effect a left turn from one freeway right of way to another—this function being assumed by the up and over lanes,  201 —referring now to  FIG. 116   b , the left turn and linking lanes,  164 , are separated from the right outer freeway lanes,  102 , with intersection spanning lane change barriers,  163 . 
         [0129]    The perimeter arc entrance extended merging lanes,  184 , can be extended back from the freeway cloverleaf,  100 , in any or all directions, allowing these lanes to function as queues for traffic seeking to exit a freeway right of way,  108  or  109 , via either a perimeter arc lane,  181 , or via exit routes available within the freeway cloverleaf,  100 , due to actual or anticipated congestion. The perimeter arc entrance extended merging lanes,  184 , branch to cloverleaf entrance extended merging lanes,  190 , that are parallel to and contiguous with the inner cloverleaf left turn and linking lanes,  164 , allowing traffic to merge from one lane to the other, and allowing the perimeter arc entrance extending merging lanes,  184 , to also function as a queue for an up and over lane entrance,  204 , or an elevated central transfer ramp entrance,  302 . Once within the footprint of the freeway cloverleaf,  100 , vehicles may merge off the perimeter arc entrance extended merging lanes,  184 , proceeding on to the at-grade park-and-ride parking area,  115 , and may then either exit the freeway cloverleaf,  100 , via a perimeter tunnel intersection,  401 , or by merging on to a perimeter arc inner merging lane,  187 , or by proceeding to an elevated central transfer ramp entrance,  302 . 
         [0130]    The perimeter arc extended exit-merging lanes,  185 , can also be extended forward from the freeway cloverleaf,  100 , in any or all directions. Although these lanes do not function directly as queues, they are related to queuing in this sense: vehicles on a perimeter arc lane,  181 , and an adjacent perimeter arc inner merging lane,  187 , can be queued using a signaling system; if they are then released to proceed to a perimeter arc extended exit-merging lanes,  185 , having an extensive length, and/or extending to the next freeway intersection exit, vehicles in the queue can be released at a faster rate. Thus, lengthy perimeter arc extended exit-merging lanes,  185 , can significantly increase the queuing capacity of a freeway cloverleaf,  100 . Lengthy perimeter arc extended exit-merging lanes,  185 , together with signaling systems controlling the total rate at which vehicles enter a perimeter arc lane,  181 , beyond the perimeter tunnel intersection,  401 , either by continuing along the perimeter arc lane,  181 , or by merging onto it from a perimeter arc inner merging lane,  187 , or, referring now to  FIG. 1   l   6   a , by entering from an up and over lane,  201 , or from an elevated central transfer ramp,  301 , referring now to  FIG. 116   b , can also ensure buses exiting the traditional cloverleaf intersection,  100 , via a perimeter arc lane,  181 , will have a low probability of being slowed by congestion. 
         [0131]    While preferred embodiments of the present invention may comprise these at-grade means for managing, reducing or preventing congestion, it will be understood that other features and attributes of preferred embodiments of the present invention are such that the further means of managing, reducing or preventing congestion detailed in this section of the specification are in many cases likely to be unnecessary and/or not cost justifiable. 
       Fifth Preferred Embodiment 
     Additional Functionality from Elevated Thru Lanes 
       [0132]    Beyond congestion management associated with at-grade lanes, considered in the last section, a fifth preferred embodiment of the present invention, referring now to  FIG. 4   c   1 , which is derived from  FIG. 4   c , and renders the lanes illustrated in  FIG. 4   c  in phantom, referring again to  FIG. 4   c   1  further comprises elevated thru lanes structures,  501 , that parallel one or both freeway right of ways,  108  and  109 , and are above an elevated central transfer area,  390 .  FIG. 4   c   1   a  is in turn derived from  FIG. 4   c   1 , but, focusing on the elevated through lane structures,  501 , illustrates in phantom only the perimeter arc lanes,  181 , providing orientation to the relationship of the elevated through lane structures,  501 , to the elevated central transfer area,  390 , and the freeway cloverleaf,  100 . 
         [0133]    Although the elevated thru lanes structures,  501 , of  FIG. 4   c   1 , and derivative illustrations, comprise two stacked lanes, further comprising an upper elevated through lane right of way in a first direction, and a lower elevated through lane right of way in an opposite second direction, it will be understood that elevated thru lanes can be rendered with an alternative, side by side design. Although the  FIG. 4   c   1  illustrations, and derivative illustrations, will be discussed with reference to North, South, East and West directions, it is understood that these are arbitrary directional designations, for more convenient discussion; although actual cloverleafs comprise two freeway routes intersecting at approximately right angles, the geographical orientation of the routes is not relevant to the operation of the present invention. 
         [0134]    Referring now to  FIG. 4   c   1   a   1 , only the upper elevated thru lanes,  502 , now referring to  FIG. 4   c   1   a , of the elevated thru lane structures,  501 , are illustrated; now referring to  FIG. 4   c   1   a   1 , the direction of these upper elevated thru lanes,  502 , are North to South and West to East. Vehicles proceeding on these lanes can exit to the elevated central transfer area,  390 , proceeding clockwise, using an elevated thru lane exit,  503 , which connects with the elevated central transfer area outer perimeter lane,  396 . Vehicles can leave the elevated central area outer perimeter lane,  396 , and can enter the upper elevated thru lanes,  502 , using an elevated thru lane entrance,  504 , merging from this entrance with the traffic proceeding on an upper elevated thru lane,  502 . 
         [0135]    Referring now to  FIG. 4   c   1   a   2 , only the lower elevated thru lanes,  505 , now referring to  FIG. 4   c   1   a , of the elevated thru lane structures,  501 , are illustrated; now referring to  FIG. 4   c   1   a   2 , the direction of these lower elevated thru lanes,  505 , are South to North and East to West. Vehicles proceeding on these lanes can exit to the elevated central transfer area,  390 , proceeding clockwise, using an elevated thru lane exit,  503 , which connects with the elevated central transfer area outer perimeter lane,  396 . Vehicles can leave the elevated central area outer perimeter lane,  396 , and can enter the lower elevated thru lanes,  505 , using an elevated thru lane entrance,  504 , merging from this entrance with the traffic proceeding on a lower elevated thru lane,  505 . 
         [0136]      FIG. 5   b  is derived from  FIG. 5   a , and is a perspective illustration of the fifth preferred embodiment of the present invention. The elevated central transfer structure,  321 , and the central transfer structure perimeter vehicle right of way,  325 , both presented earlier and comprised by the first preferred embodiment, correspond in function to the elevated central transfer area,  390 , and the elevated central transfer area outer perimeter lane,  396 , respectively, just discussed with reference to  FIG. 4   c   1   a  and derivative illustrations. Referring again to  FIG. 5   b , elevated thru lane structures,  501 , upper elevated thru lanes,  502 , elevated thru lane exits,  503 , elevated thru lane entrances,  504 , and lower elevated thru lanes,  505 , are labeled, and function as described above when referencing  FIG. 4   c   1   a  and derivative illustrations. 
         [0137]    One purpose of the fifth preferred embodiment of the present invention is to provide functionality linked to a transit cloverleaf of the present invention designed to reduce congestion on freeways, and/or other roads, by means of dedicated lanes with traffic volumes controllable by means comprising but not limited to: signaling systems, and toll charging systems. A further purpose of the fifth preferred embodiment is to provide means for better linking a transit cloverleaf of the present invention with retail and other businesses in the vicinity of a transit cloverleaf. A further purpose of the fifth preferred embodiment is to provide functionality that will promote ride sharing, Park-and-Ride, and the use of bicycles. The elevated thru lane structures,  501 , may include a dedicated lane for bicycles, segways, scooters and other means of individual locomotion that are of limited suitability, or are unsuitable, for inclusion amidst vehicular traffic. 
         [0138]    While the fifth preferred embodiment of the present invention comprises, referring now to  FIG. 4   c , an elevated central area,  390 , or, referring now to  FIG. 5   b , an elevated central transfer structure,  321 , or an alternate structure that is substantially the functional equivalent of the elevated central area,  390 , or the elevated central transfer structure,  321 , it may or may not include some or any of other elements comprised in other preferred embodiments and presented in this specification. Specifically, but not limited to the following enumeration, referring to  FIG. 4   c , the fifth preferred embodiment need not comprise either one, or more than one, of these elements or their functional equivalents: perimeter tunnel intersection(s),  401 , up and over lane(s),  201 , elevated central transfer ramp(s),  301 , elevated Park-and-Ride ramp(s),  341 , perimeter arc inner merging lane(s),  187 , transfer elevator(s),  170 , elevated central transfer area outer pedestrian boulevard(s),  394 , central transfer area bus transfer point(s),  392 , elevated central transfer area inner perimeter lane(s),  393 .