The present invention relates to a flyover bridge for a road intersection.

The modern-day problem of urban and suburban traffic congestion is a well- known phenomenon that takes place in countries all over the world. The root of the problem is grounded in the nature of surface travel along predetermined routes. At some point, two such predetermined routes must cross each other.

At the point of intersection, only traffic flowing along one of these routes can proceed at any given time. The most common solution for maintaining an orderly flow of traffic is the traffic light. Due to the complicated timing patterns for traffic lights at an intersection, these could be inefficient at congested intersection especially during rush hour.

Another conventional solution to the problem posed by the crossing of two traffic routes is to elevate one of the routes allowing the other to pass underneath. It is an improvement over traffic lights because it allows both routes to proceed simultaneously rather than alternately, thereby allowing an increased volume of traffic along each route.

However construction of traditional multi-level intersection system, such as a clover leaf or another similar system requires quite a sizeable lot of land and is often found all but impractical in areas where, such as urban centres, land prices are forbidding. Moreover, for aesthetic reasons, more than two grade levels seem not possible in an urban area.

Furthermore, existing single-level routes intersections would not be modified and transformed into a large scale design such as the clover leaf system because to rebuild existing intersections is extremely difficult, costly if not impossible at all in busy urban area where a substantially uninterrupted traffic flow must be maintained at all time.

The present invention aims at solving the above noted problems. The present invention is intended to provide a new intersection system, in particular a new elevated flyover bridge, which uses less land, is small in scale to thereby permit use in city environment and yet is convenient for automobiles to go straight on or turn right or left, either entirely free of interruption by traffic lights or 5 subject to the least possible interruptions. Another aim of the present invention is to provide an intersection system which is suitable to be built by reforming an existing road intersection.

The object of the present invention is a flyover bridge designed to connect two road sections leading to an intersection by passing over the said intersection io and the other road sections which lead to it, characterised in that it is

unidirectional, in that it is curved in a plan parallel to the plan of the intersection so as to reduce the longitudinal distance between its two ends; and in that the roadbed of the flyover bridge is inclined with respect to a plan parallel to the plan of the intersection towards the radius of the curvature.

i s The foregoing and other objects, features and advantages of the present invention will be apparent from the following more particular description of several preferred embodiments of the invention as illustrated in the accompanying drawings.

Figure 1 is a schematic perspective view of an embodiment of an 0 intersection system comprising two flyover bridges according to the invention.

Figure 2 is a plan view from above of figure 1.

Figure 3 is a plan view of another embodiment of an intersection system according to the invention.

Figure 4 is a sectional view of the flyover bridge illustrated in figure 3 along 5 the line IV-IV.

Figure 5 is a partial schematic view of the roadbed of a flyover bridge according to the invention.

Figure 6 is a sectional view of figure 5 along the line VI-VI. Figure 7 is a sectional view of a flyover bridge according to a third embodiment of the invention.

The following description does refer to specific directions such as north, south, east and west for the purpose only of describing the relationships of the 5 roads relative to each other. However, referring to specific directions is only for the purpose of explanation and does not limit the particular orientation of the various roads relative to the earth's magnetic north.

Figures 1 and 2 illustrate various sections of roads leading to an l o intersection. The intersection, generally indicated by the reference numeral 10 is formed in this embodiment of five sections of roads. The orientation of these road sections will be described in the following with reference to figure 2.

The first road section 1 runs north-south and includes a plurality of opposite traffic lanes: northbound lanes 1 1 and southbound lanes 12. In this embodiment, 1 5 the northbound lanes 1 and the southbound lanes 12 are separated by a no

traffic band 13 that could be a strip of grass for example.

The second road section 2 runs south west - north east and includes a plurality of opposite traffic lanes: north-eastbound traffic lanes 21 and south- westbound traffic lanes 22. As for the first road section 1 , the north-eastbound 0 traffic lanes 21 and the south-westbound traffic lanes 22 of the second road

section 2 are separated by a no traffic band 23 that could be a strip of grass for example.

Evidently, the northbound lanes 1 and the south bound lanes 12 of the first road section 1 and the north-eastbound lanes 21 and the south-westbound lanes 5 22 of the second road section 2 could respectively be immediately adjacent.

The third and the fourth road sections 3, 4 run both east-west and include both a plurality of eastbound and westbound traffic lanes (not illustrated in figure 1 and 2), while the fifth road section 5 (figure 2) runs south-east-north-west and also includes a plurality of south-eastbound traffic lanes and north-westbound traffic lanes (not illustrated in figures 1 and 2).

In this embodiment illustrated in figures 1 and 2, a first unidirectional flyover bridge 6 connects a north-eastbound traffic lane 21 a of the second road section to a northbound lane 1 1 a of the first road section passing over the intersection 10 and the third, fourth and fifth road sections 3, 4, 5 thus permitting for a continuous traffic flow from the first to the second road sections 1 , 2 in an essentially north direction. In the same way, a second unidirectional flyover bridge 7 connects a southbound lane 12a of the first road section 1 to a south-westbound lane 22a of the second road section 2.

Hence, due to the first and second flyover bridges 6, 7 there is no need for traffic lights to regulate the traffic going straight from the first road section 1 to the second road section 2 in either directions, the said flyover bridges 6, 7 according to the invention allowing both routes to proceed continuously and simultaneously.

Further more, a vehicle on the northbound traffic lanes 11 of the first road section 1 wishing to go left or right and join any one of the third, fourth or fifth road sections 3, 4, 5 can do so normally by following a different northbound lane 1 1 b not leading to the flyover bridge 6. Even though traffic lights may be needed, the traffic flow from either one of the first or second road sections 1 , 2 to either one of the third, fourth or fifth road sections can be fluidized and handled with less interruptions due to the fact that the traffic flow going straight from the first road section 1 to the second road section 2 has no influence on the rest of the traffic at the intersection 10 due to the flyover bridges 6, 7.

Figure 3 illustrates another embodiment of the invention in which four road sections lead to an intersection 20.

In this embodiment, the first and second road sections 100, 200 run east- west while the third and the fourth road sections 300, 400 run north-south.

The first and second road sections 100, 200 include a plurality of eastbound lanes 1 10, 210 and westbound lanes 120, 220. A first unidirectional flyover bridge 60 connects an eastbound traffic lane 210a of the second road section 200 to an eastbound traffic lane 1 10a of the first road section 100 passing over the third and fourth road section 300, 400 thus permitting for a continuous traffic flow straight from the second to the first road section 2, 1 and straight from the third road section 300 to the fourth road section 400. In the same way, a second unidirectional flyover bridge 70 connects a westbound traffic lane 120a of the first road section 100 to an east bound traffic lane 220a of the second road section 200.

Like in the first embodiment, due to the first and second flyover bridges 60, 70 there is no need anymore for traffic lights to regulate the traffic going straight from the first road section 100 to the second road section 200 in either direction. - Moreover, the rest of the traffic flow passing through the intersection 20 can then be less interrupted and fluidized due to the fact that the traffic flow from the first to the second road sections 1 , 2 has no influence on it anymore.

The technical features of the flyover bridge 6, 7, 60, 70 according to the invention will be now further described with reference to figures 4 to 7.

It is an essential characteristics of the present invention that the

unidirectional flyover bridge 6, 7, 60, 70, described for example in figures 1 , 2 and 3, is not straight but is rather curved in a plan parallel to the plan of the road sections (horizontal plan). For example, each of the flyover bridge 6, 7, 60, 70 illustrated in figures 1 , 2 and 3 present at least one curve 8, 80. This characteristic allows reducing the longitudinal dimensions of the flyover bridge according to the invention in comparison to existing rectilinear straight flyover bridge while keeping the same angle of ascent. By longitudinal dimension of the bridge, it is meant the straight distance between the two ends 6a, 7a, 60a, 70a of the bridge (as opposed to the actual length of the bridge which shall be the length of the roadbed 6b, 7b, 60b, 70b of the bridge). For example, figure 3 illustrates how with a flyover bridge 60, 70 according to the invention the longitudinal dimension A needed by a rectilinear bridge 90 such as known from the prior art (represented by dotted lines in figure 3) can be reduced to a longitudinal dimension B of the flyover bridges 60, 70 according to the invention due to their curvature. The more curved the curve 8, 80 of the flyover bridge according to the invention, the shorter the longitudinal distance between the two ends 6a, 7a, 60a, 70a of the flyover bridge 6, 7, 60, 70.

Hence, the flyover bridge according to the invention while offering the same efficiency as a known elevated bridge in allowing a continuous traffic flow has a reduced scale more suitable for use in an urban area or in an existent intersection.

To facilitate the passing of the said curve 8, 80, the roadbed 6b, 7b, 60b, 70b of the flyover bridge 6, 7, 60, 70 according to the invention is significantly inclined towards the radius of the curve 8, 80. This inclination of the roadbed 6b, 7b, 60b, 70b in the curve 8, 80 is illustrated for example in figures 4 and 6.

In terms of construction, the roadbed 6b, 7b, 60b, 70b of a flyover bridge according to the invention is preferably made of vertical, welded, bent, metallic strips called cells 81. These cells 81 are illustrated for example in figure 5. The cells 81 can be shaped so as to form a honeycomb structure such as illustrated in figure 5. Preferably the shape and dimension of the cells are designed in an optimal way in order to provide the maximal coupling with tires of a vehicle travelling on the flyover bridge. Preferably, the edges of the cells 81 present notching which further increase the coupling with the tires of a vehicle.

Preferably, the roadbed 6b, 7b, 60b, 70b of a flyover bridge 6, 7, 60, 70 according to the invention is further designed so as to be able to clear itself from snow, or small debris which could accumulate on the said roadbed. More precisely and as illustrated in figure 5, the said snow, dust and small debris are pressed down under the pressure of the tires through the cells 81 in a special container 82 placed under the roadbed 6b, 7b, 60b, 70b where they are collected.

Preferably and as illustrated in figure 7, there are airways 83 inside the said container 82 supplying warm air with the help of powerful fans 84 in order to eliminate icing on the roadbed during winter or to maintain the roadbed 6b, 7b, 60b, 70b non slippery in areas with high humidity. The flyover bridge according to the invention has many advantages: it allows continuous traffic in at least two directions and permits to eliminate traffic lights in those directions. The curvature of the said flyover bridge while not stopping the traffic forces the vehicles to slow down to a safe speed level. Due to the said curvature of the flyover bridge, the longitudinal distance between the two ends of the flyover bridge according to the invention can be greatly reduced, hence offering an efficient solution for congested intersections having small scale ideal to use in an urban area. Moreover, due to its small scale and its light construction, flyover bridges according to the invention can be fitted at low cost on any existing intersections to connect any one of the road sections leading to the said intersection and with limited aesthetic impact.