WO2014094693A1

WO2014094693A1 - Circular intersection with lighted warning device

Info

Publication number: WO2014094693A1
Application number: PCT/CZ2013/000165
Authority: WO
Inventors: Petr NOVOTNÝ; Jan VÁCHAL; Marek VOCHOZKA
Original assignee: Novotn Petr
Priority date: 2012-12-19
Filing date: 2013-12-11
Publication date: 2014-06-26
Also published as: DE212013000257U1; CZ2012923A3; SK7624Y1; CZ304271B6; SK50222015U1

Abstract

A circular intersection (1) with center island (3) and roundabout (2) which connects to approaching roadways (4, 4', 5, 5'), having, on the center island (3), a lighted warning device with warning light (10), operating in guiding mode by rotation and in warning mode by flashing, connected with a control unit (8). The device is further equipped with a highlighting and guiding lighted ring (6), also connected to the control unit (8). The periphery of the ring (6) is equipped with a light source (7) that consecutively and continuously turns on and off, creating an optical impression of a ring (6) rotating in the direction of travel inside the roundabout (2). In warning mode, e.g. in the event of an accident or traffic jam, the light source (7) flashes with a pulse and informs drivers of the traffic situation. Both these lighting elements (6, 10) may be controlled through a control unit (8) by speed sensors (11, 13) that monitor the speed of vehicles approaching the circular intersection (1). The guiding and warning modes primarily have a preventive function for preventing the risk of traffic accidents and reducing the rate of accidents. The circular intersection (1) is characterized by improved traffic flow and increased traffic safety, especially in the dark and in poor visibility.

Description

Circular intersection with lighted warning device

Field of the invention

The invention relates to the type of circular intersections with "roundabouts" that are equipped with a lighted warning device alerting the driver of the approaching roundabout for the purpose of increasing the driver's attention and reducing speed upon entering the roundabout.

Background of the invention

Circular intersections, the basis of which are roundabouts, are becoming increasingly important in modern project designs for transportation systems and roads. Their advantage lies, among others, mainly in increasing safety and capacity as well as improving the traffic flow that results from the slowdown which itself is a result of the change of curvature of the trajectory, where the driver does not see into the intersection over the raised center island and must slow down to yield to vehicles approaching from the left from inside the roundabout from the side or from the opposite direction.

In the most common design, the circular intersection has a circular shape, forming the roundabout with a central island. There are three, but even up to six approximately right-angled two-lane or multi-lane roads connecting into the roundabout, the imaginary axis of the roads running approximately through the middle of the center island.

Lanes of opposing traffic on the roadways are usually separated by dividing wedge- shaped lane separators before arrival at the roundabout. If it is a multi-lane roadway, the individual lanes may also be separated by wedge-shaped separators before the roundabout. The lanes before the arrival to the roundabout generally curve so that the entrance of the vehicle is smooth. The driver recognizes the circular intersection by vertical or horizontal road traffic signs and by the center island which forms a visible barrier to driving straight when approaching the circular intersection. The guidance elements for guiding the vehicle into the roundabout are made up of vertical or horizontal traffic signs as well as the aforementioned wedge-shaped lane separators and the curving lanes before arrival to the roundabout. Warning light devices are basically not utilized at ordinary roundabouts, with the exception of orange flashing lights drawing attention to a crosswalk if the roadway of the circular intersection is fitted with a crosswalk.

Circular intersections with common guiding elements are difficult to see particularly in the dark or in poor visibility conditions, when the driver can easily overlook the traffic signs and center island, and accidents often occur at roundabouts as a result of not adjusting speed when entering roundabouts which, in addition to increasing the flow of traffic, are supposed to promote an increase in safety.

Circular intersections in rural areas very often have no artificial lighting. Illuminating roundabouts is an issue dealt with more in urban areas, with the majority of them made up of conventional public lighting, i.e. fluorescent lights on poles situated along the access roads and in the circular intersection itself. Public lighting is expensive in terms of both overhead and operating costs. Its effectiveness in relation to safety and visibility of the circular intersection is low, as it illuminates a wide area, including adjacent buildings, billboards and other objects that distract the driver's attention, so the circular intersection can easily be overlooked, and the driver may not reduce his speed to a safe value while approaching the circular intersection. In urban areas of cities and towns, permanent lighting has another disadvantage in that it is a leading cause of "light pollution" which adversely affects the quality of life of the residents of neighboring houses and flats.

The document WO 9746990A1 describes a solution for lighting an intersection which may be transformed into a circular intersection by the extrusion of a central island above the level of the roadway. This extruded island may be fitted with a lighted arrow that shows the direction of travel along the roundabout. At the same time, the circular intersection is lit by public lighting that illuminates the lanes of the roundabout. The guiding element formed by a lighted arrow has the disadvantage that is static, not very visible, and can be confused with a lit advertisement, particularly in urban areas and municipalities, thus being ignored by the driver. The solution according to WO 9746990 due to its static function does not inform the driver about the condition of traffic in a circular intersection and does not truly fulfill a warning function.

Utility model CZ 014 367 describes a circular intersection, the center island of which is fitted with elements of different geometric shapes which themselves are fitted with either internal or external lighting equipment. The point of this solution is merely to only improve the aesthetic level of the center island, not to alert the driver of the approaching circular intersection, guiding him into the roundabout, or reducing the approach speed. This solution also has a minimal warning effect.

The task of the invention is to provide a solution to circular intersections with a warning light device that overcomes the above mentioned drawbacks of known solutions and that is capable of informing drivers about the circular intersection from a distance, and in addition is able to work in various modes in order to signal drivers about normal traffic, increased traffic, an accident or risk of accident caused by an approaching vehicle not adjusting its speed, or another extraordinary situation on a circular intersection that the driver cannot see from his viewpoint upon approach and consequently cannot evaluate and adjust his speed.

Summary of the invention

This objective is resolved by creating a circular intersection with a lighted warning device according to the present invention.

A circular intersection in the known method involves a roundabout with a raised central island, where at least three roadways are connected to the roundabout, each of which has at least two lanes fitted with at least one lighted warning device. The essence of the invention is that the lighted warning device includes at least one warning light arranged on the central island visible from each roadway and connected to a control unit for changing the operating mode of the warning light from guidance mode with a warning light rotating in the direction of travel in the roundabout and/or a flashing warning light with a frequency of 0.1 to 3 Hz to alarm mode with a flashing warning light with a frequency of 5 to 20 Hz. In guidance mode, the warning light (e.g. an orange beacon with light source fitted with a rotating screen) turns at a slow speed and draws the driver's attention, guiding him into the roundabout. Alternatively, the warning light may flash slowly. In warning mode, e.g. for the danger of an imminent traffic accident or another dangerous situation, the warning light stops turning, and the warning light begins to flash with an increased frequency, or its color changes to red.

The warning light is preferably arranged on top of a separate supporting base or on top of the raised central island which is formed as a convex. The elevated location of the warning light leads to its improved visibility and draws attention to the circular intersection. Its real visibility is more than 500 m.

In an advantageous embodiment, the circular intersection also includes a highlighting and lighted guiding ring set up so that it is visible from each roadway, wherein the circumference of the lighted guiding ring is composed of consecutive lights progressively and continuously turning on and off, thus creating the optical impression of a ring rotating in the direction of travel along the roundabout. An appropriate choice of light colors, such as orange, which is characteristic of directional light, and an optical impression of slowly rotating lights will inform the driver at a long distance before the circular intersection that he is approaching the roundabout, especially at night or in poor visibility, and he can adjust his driving speed.

An highlighting and guiding lighted ring is connected to a control unit for changing the operating mode of the light sources from guiding mode generating an optical impression of a rotating ring to warning mode of all or at least part of the flashing lights simultaneously. Warning mode is primarily designed to prevent traffic accidents. Warning mode can also be used in the event of an already-existing accident, e.g. in the event of a traffic accident or other extraordinary traffic situation on circular intersections or on adjacent roads. The control unit, consisting of a conventional electronic switching device, can be operated manually or by remote access. In an advantageous embodiment, the highlighting and guiding lighted ring is connected to a control unit for regulating the speed of sequentially switching the lights on and off in in a range of 5-10 m s^"1. This angular velocity is proportional to the recommended speed of vehicles passing through a circular intersection, which is approximately 7 m s^"1. When approaching a roundabout, the driver of the vehicle subconsciously and automatically adjusts his vehicle speed to the speed of the fictitious rotation of the highlighting and guiding lighted ring.

The highlighting and guiding lighted ring is preferably circular, elliptical, or oval in shape and may be arranged on a separate support base located on the central island or directly on the surface of the raised central island, which is formed as a convex.

It may also be advantageous if the supporting base or convex central island is at least partly fitted with a reflective layer, fluorescent layer, or illuminated element, or even a self-cleaning layer. The support base or convex center island is also more visible and identifiable for the approaching driver, especially at night and during poor visibility, when the reflective, fluorescent, or lighting elements are clearly visible.

Currently, intelligent vehicles are being tested which are capable, based on captured data from the roadway and from equipment implemented either inside or alongside the roadway, of actively controlling the car, or taking some control elements over from the driver during critical situations, thus averting an impending accident. The area inside the center island or the support base may preferably be adapted for such systems in such a way that it is fitted with a device for actively transmitting information with a variable output (for example, according to speed or vehicle weight) and may be formed as substantially reflective to electromagnetic or other waves. It may also be formed from materials or layers with are self-cleaning capabilities, e.g. from nanotechnological materials, materials with a photocatalytic effect, etc.

In an advantageous embodiment, the highlighting and guiding lighted ring is formed by a lighted tube divided into individual arc segments fitted with lights that turn on and off by themselves. The lights may be e.g. LED, halogen lamps, incandescent lamps, or another suitable light source. The lighted ring may also be fitted with other auxiliary optical elements, particularly reflective or diffuse elements, for optimum luminance and visibility.

In another advantageous embodiment of the circular intersection according to the invention, the edges of the roadway before the circular intersection are equipped with first speed sensors for measuring the speed of vehicles approaching the circular intersection; these are connected with a control unit for automatically changing the operating mode of the highlighting and guiding lighted ring and/or the warning lights when a speed higher than the safe (permitted) speed is measured. The speed sensors may be formed by speed measuring radars which can be supplemented with an information display for displaying the measured values of the speed of the vehicle approaching the circular intersection. Speed sensors make up another element of increasing the safety of the circular intersection, since they detect and signal the speed of the approaching vehicle, and activation of the warning mode of the highlighting and guiding lighted ring and/or warning light warn the driver in an unmistakable way of the necessity of reducing his speed.

The warning mode is designed primarily for preventing traffic accidents. Equipment in this mode operates such that in the event that the first speed sensor detects that a vehicle is approaching the circular intersection at a high speed which would require intense braking to slow down to the recommended speed at the entrance to the circular intersection, the control unit sets the warning mode. In this warning mode, the frequency of the flashing highlighting and guiding lighted ring and/or the warning light speeds up. At the same time, it slows down when the optical rotation of the highlighting and guiding lighted ring stops.

In a related advantageous embodiment, there is a second set of speed sensors at the edge of the roadway or at the wedge-shape lane separators before the arrival location at the roundabout for measuring the speed of vehicles entering the roundabout; these are connected to a control unit to automatically change the operating mode of the highlighting and guiding lighted ring and/or warning light when a speed faster than the permitted speed is measured. The second speed sensors represent another level of warning mode. Their design is similar to the first speed sensors and their function is as follows: If the vehicle does not respond to notices of unsafe speed before the first speed sensors, the warning issued by the highlighting and guiding ring and warning light are intensified. In contrast, if the second speed sensor detects a safe speed at all entrances, both light systems (highlighting and guiding light ring and warning light) enter into guidance mode.

The first and the second speed sensors may alternatively be replaced by non-contact sensors for measuring the mass or kinetic energy of the vehicle approaching the circular intersection, given the fact that the instantaneous kinetic energy, which is a function of the weight and the instantaneous velocity, is the decisive factor for braking a vehicle. These sensors are considered the equivalent of the speed sensors.

In another advantageous embodiment of the invention, the wedge-shape lane separators are fitted with an additional warning light connected to the control unit and/or first speed sensor for signaling the high speed of vehicles approaching the circular intersection. This design is particularly suitable for larger flat circular intersections where the approach to the roundabout is longer. The additional warning lights may be activated either manually or by remote access. Their main warning function, though, is activated by a signal from the first speed sensor, i.e. in advance of the approach to the roundabout. This factor as well is especially effective in the dark or in poor visibility.

In another advantageous embodiment of the circular intersection according to the invention, lighting fixtures are arranged in the area where the roadway connects with the roundabout which detect the arrival of the vehicle and illuminate part of the roadway and roundabout only during the passage of vehicles. The entrances to the roundabout are potential contact points between vehicles, and it is therefore appropriate to illuminate them to increase safety, especially at the moment of arrival of vehicles to the roundabout and during their passage through this part. The detection of vehicles may be carried out using e.g. motion sensors, or by connecting the lighting fixtures to the first or second speed sensor. Finally, it is advantageous that the circular intersection is fitted with at least one solar photovoltaic panel for charging at least one device from the following group: highlighting and guiding lighted ring, warning light, control unit, speed sensors, additional warning light, and lighting fixture.

The advantages of the circular intersection according to the invention consist mainly in a significant increase in safety and reduction in the risk of accidents. Other advantages include improving the flow of traffic on circular intersections, in savings in overhead and operating costs for public lighting, and ultimately in a reduced load of light pollution in urban cities and towns.

Description of the drawings

The invention is more clearly illustrated by the drawings, in which Figure 1 shows a layout view of a circular intersection, Figure 2 is a perspective view of the highlighting and guiding lighted ring and warning light arranged directly on the convex central island, and Figure 3 is a perspective view of a guiding lighted ring and warning light arranged on a support base located on the central island.

Examples of the preferred embodiments of the invention

It should be understood that the individual realizations of the invention are presented solely for illustrative purposes and not as a limitation of the invention to the number of examples presented here. Experts who are familiar with the state of technology shall find, or using routine experimentation will be able to determine, many equivalents to the specific realizations of the invention which are specifically described here. These equivalents shall also be included into the scope of the claims.

Figure 1 shows a layout view of a circular intersection with a roundabout 2, in the center of which is located a raised center island 3. There are two opposite four-lane roadways 4, 4J. at the roundabout 2 which form the main transport route, and two opposing two-lane roadways 5, ί which form the adjacent transport route. The four- lane roadways 4, 4_ and the two-lane roadways 5, ί are further fitted with separate turn lanes 17 that run outside the roundabout 2. The individual lanes on roadways 4, 41. 5- §1 are mutually separated before the arrival to the roundabout 2 by wedge- shaped separators 12.

The circular intersection is equipped with a number of detection, signaling, warning, and guiding elements. Along the edge of the roadways 4, 4^, 5, ί , the first speed sensors 1 are installed at a sufficient distance before the circular intersection. These are the "radars" measuring the speed of the vehicle approaching along the roadways 4, 41, 5, 51 to the circular intersection, and signal the measures speed on a large- screen digital display. The first speed sensors H are connected to additional warning lights 14 set into the wedge-shaped lane separators 12 of the roadways 4, 4_ , 5, fT, and with the control unit 8 illustrated in Figures 2 and 3, through which the other guiding and warning elements are controlled as will be described hereinafter.

The additional warning light 14 consists of a beacon or a pulsing/flashing light which is activated as soon as the first speed sensor 11. measures a speed faster than that permitted or recommended of a vehicle approaching the circular intersection Λ along the respective lane of the roadway 4, 4_1, 5, 5_1 where the first speed sensor 11. is installed. The driver is thus informed of his high speed not only by the display of the first speed sensor H , but also by the additional orange warning light 14.

A similar function is held by the second speed sensor 13 installed on the wedge- shaped lane separators 12 of roadways 4, 4_ , 5, 5_1 just before the entrance into the roundabout 2. These second speed sensors 13 are not equipped with a digital display, but they are connected to a control unit 8 illustrated in Figures 2a and 3, through which the other guiding and warning elements are controlled, as will be described hereinafter.

The speed sensors H, 13 may alternatively be replaced by sensors for measuring the mass and/or kinetic energy of the incoming vehicles.

At the locations where the roadways 4, 5, ί connect to the roundabout 2 , there are lighting fixtures 15 installed on poles that illuminate the respective part of the roadways 4, 4_1, 5, 5 and roundabout 2 only for as long as the vehicle is passing through this part. These are common electric lights that are activated either by a motion sensor (not pictured), or on the basis of a signal from the first speed sensor 11 or second speed sensor 13, connected to a lighting fixture 15 either directly or through a control unit 8.

The most important guiding and warning element of the circular intersection is the warning light 10, which in the illustrated example in Figures 2 and 3 is a beacon, i.e. a spotlight with a rotating screen with an optical diffuser. The warning light 10 is also connected to a control unit 8 and, similarly like the guiding lighted ring 6, works in both guiding regime and warning regime. In the guiding regime, the warning light 10 slowly rotates in the direction of travel along the roundabout 2. This alternatively may also be a slowly flashing light. The color of the warning light is orange, but in a preferred design has at least two selectable colors. The frequency of rotation or flashing is approximately 30 oscillations per minute, i.e. 0.5 Hz. Transition to warning mode may occur similarly like for the guiding lighted ring 6 through a manual or remote command, as well as on the basis of a signal from the respective first speed sensor 1 or second speed sensor 13. In warning mode, the warning light flashes at an increased frequency of 10 Hz, or may change to the color red. If the light is a rotating beacon, the warning light 10 stops rotating, and may flash only in the critical direction of the approaching speeding vehicle. Another important element is the highlighting and guiding lighted ring 6, illustrated in detail in Figure 2, where it is an integral part of the convex center island 3, and in Figure 3, where it is arranged on a support base 9. The lighted highlighting and guiding ring 6 in both examples is arranged so that part of its periphery is visible from the approaching direction of each roadway 4, 4J_, 5, ( , i.e. it is raised in relation to the level of the roadways 4, 4_ , 5, fT. The periphery of the guiding lighted ring 6 is formed by lights 7 that consecutively and continuously turn on and off, creating an optical impression of a ring 6 rotating in the direction of travel inside the roundabout 2. This is achieved in that the ring 6 has a circular shape and is made of a lighted tube divided into individual separate arc sections that turn on and off ( , §T_, fitted with LED light sources 7. Each arc section ( , 6 is fitted with a number of LED lights, so that when a respective section ( , is lit up, the section ( , §T_ lights up as a single unit. Each section ( , 6^ may also be fitted with several rows of LED lights of different colors, so that the colors of the lights of the individual sections ( , (T[ or the entire guiding lighted ring 6 can change. The lighting mode of the guiding lighted ring 6 is controlled by a control unit 8, which is known by experts as an electronic or electromechanical switching device equipped with electrical circuits for changing the individual lighting modes. This also may be a programmable device in which appropriate software can change the lighting mode in a creative way. The control and configuration for the control unit 8 may take place either manually or by remote access.

In other executed examples, not illustrated here, the guiding lighted ring 6 may be formed in a different method than as a lighted tube, e.g. this may be a discreet light source 7 located along the periphery of the center island 3, or a light source 7 arranged in a shape other than a circular, elliptical, or oval shape.

During normal operation, the highlighting and guiding lighted ring 6 works in guidance mode, meaning it creates the optical impression of a ring 6 rotating in the direction of travel inside the roundabout 2. Especially in the dark or in poor visibility, it effectively warns the driver of the approaching roundabout 2 and leads to a reduction in travel speed and to an approach in the proper direction. The speed at which the lights consecutively turn on and off is controlled by the control unit 8, and maintains it at a value of approximately 7m s^"1, which is the recommended speed for a vehicle approaching a roundabout 2 and passage through the roundabout 2. The guiding lighted ring 6 may pass into warning mode. The control unit 8 may receive an impulse to change the mode e.g. manually or remotely in the event of a traffic accident, the risk of one, or another extraordinary situation either at the circular intersection 1 or in its close proximity. In normal operation, the switch to warning mode follows after the evaluation of the signal of the respective first speed sensor H or second speed sensor 13 by the control unit 8. On the basis of this signal, if the signal of the vehicle approaching the circular intersection 1_ or already entering the roundabout 2 is evaluated as supercritical, the guiding lighted ring 6 is switched by the control unit 8 into warning mode.

In warning mode, the guiding lighted ring 6 flashes as a pulse, meaning that all light sources 7 flash at the same time, or at least a part of the lights 7 flash that are located opposite the respective roadways 4, 5, ί along which the dangerous vehicle is approaching. The optical "rotation" of the guiding lighted ring 6 may slow down in warning mode, or stop, or change the direction of rotation, or change color. The driver is thus informed about the dangers and may adjust his driving speed to the optical warning signal, especially at night or in poor visibility.

The warning light 10 is positioned above the guiding lighted ring 6 and informs the driver from a greater distance of the approaching circular intersection 1_. In the example illustrated according to Figures 2 and 3, the guiding lighted ring 6, warning light 10, and control unit 8 form integral parts of the dome-shaped body 8 in the shape of a spherical segment which forms part of the raised center island 3 (Figure 2), or is arranged on the support base 9 formed by a welded steel construction on the center island 3. The individual parts of the surface of the dome-shaped body 18 are equipped with a reflective or fluorescent layer, thus improving the visibility of the dome-shaped body 18 and forming another warning and safety element, which can, for example, in the event of a power failure, serve as a substitute for the electrically powered elements. Some of the elements may be powered by a solar photovoltaic panel 16. Alternatively, the surface of the dome-shaped body 18 may be fitted with elements that actively transmit information through the detected approaching vehicles. Currently, intelligent vehicles are being tested which are capable, based on captured data from the roadway and from equipment implemented either inside or alongside the roadway, of actively controlling the car, or taking over some control elements from the driver during critical situations, thus averting an impending accident. The area inside the center island 3 (which could be the surface of the dome-shaped body 18 or the support base 9) is, for these purposes, equipped with a device 19 for actively transmitting information with a variable output (for example, according to speed, vehicle weight, or kinetic energy of the vehicle). This is basically a device which transmits electromagnetic, optical, or other signals 20, or a surface which significantly reflects these signals 20.

The respective part of the surface of the center island 3, the dome-shaped body 18, or the support base 9 may also be fitted with layers with self-cleaning capabilities.

In other executed examples, not illustrated here, the guiding lighted ring 6 and warning light 10 may be on various types of support constructions which may serve to hold other technical or information elements, such as the symbols of cities or towns. Industrial applicability

The invention can be used in the construction and reconstruction of circular intersections with roundabouts to increase their safety and visibility by actively responding to the dangerous behavior of vehicles, which will consequently reduce the accident rate on these circular intersections.

Overview of the positions used in the drawings

1 circular intersection

2 roundabout

3 center island

4 four-lane roadway

4^' four-lane roadway

5 two-lane roadway

5^' two-lane roadway

6 highlighting and guiding lighted ring

6^' arc section of the guiding lighted ring

6" arc section of the guiding lighted ring

7 light source/light

8 control unit

9 support base

10 warning light

11 first speed sensor

12 wedge-shaped lane separator

13 second speed sensor

14 additional warning light

15 lighting fixture

16 photovoltaic panel

17 turn lane

18 dome-shaped body

9 device for actively transmitting information

20 signal of the device for actively transmitting information

Claims

1. A circular intersection (1) that includes a roundabout (2) with a raised center island (3), where the roundabout (2) is connected to at least three roadways (4, 4', 5, 5'), each of which having at least two lanes, fitted with at least one warning lighted device, characterized in that the warning lighted device includes at least one warning light (10) which is arranged in the area of the center island (3), visible from each roadway (4, 4^', 5, 5^'), and is connected to a control unit (8) to change the operating mode of the warning light (10) from guiding mode with rotation of a warning light ( 0) in the direction of travel inside the roundabout (2) and/or a flashing warning light (10) with frequency 0,1 to 3 Hz, to a warning mode with a flashing warning light (10) with frequency 5 to 20 Hz.

2. A circular intersection (1) according to claim 1, characterized in that it also includes a highlighting and guiding lighted ring (6) arranged visibly from each roadway (4, 4^', 5, 5') below a warning light (10), while the periphery of the highlighting and guiding lighted ring (6) is formed by a light source (7) that consecutively and constantly turns on and off, creating an optical impression of a ring (6) rotating in the direction of travel inside the roundabout (2), and the ring (6) is connected with the control unit (8) to change the operational mode of the light sources (7) from guiding mode, which creates the optical impression of a rotating ring (6) to notify about the circular intersection (1) and entrance into the roundabout (2), to warning regime of all or at least part of the simultaneously flashing lights (7) to increase driver attention and to inform of an impending accident.

3. A circular intersection according to claim 2, characterized in that the guiding lighted ring (6) is connected to a control unit (8) to regulate the speed of the consecutive turning on and off of the light sources (7) within a range of 5 to 10 m s^"1.

4. A circular intersection according to at least one of claims 2 to 3, characterized in that the highlighting and guiding lighted ring (6) has a circular, elliptical, or oval shape, and is arranged on a separate support base (9) situated on a center island (3), or directly on the surface of a raised center island (3) which has a convex shape.

5. A circular intersection according to at least one of claims 1 to 4, characterized in that the warning light (10) is arranged on the top of the separate support base (9) or on the top of a raised center island (3), which has a convex shape.

6. A circular intersection according to claims 3 to 5, characterized in that the support base (9) or convex center island (3) or the surface of the center island (3) is at least partially fitted with a reflective layer or fluorescent layer or a shining element, eventually a self-cleaning layer.

7. A circular intersection according to at least one of claims 1 to 6, characterized in that the highlighting and guiding lighted ring (6) is made up of a lighted tube divided into individual arc sections (6^', 6^") fitted with light sources (7) that turn on and off separately.

8. A circular intersection according to claims 1 to 7, characterized in that the edge of the roadways (4, 4^', 5, 5^') before the circular intersection (1) are fitted with the first speed sensors (11) to measure the speed of vehicles approaching the circular intersection (1); these sensors are connected with a control unit (8) to automatically change the operating mode of the guiding lighted ring (6) and/or the warning light (10) when a speed higher than the permitted speed is measured.

9. A circular intersection according to claims 1 to 8, characterized in that the edge of the roadways (4, 4^', 5, 5^') or the wedge-shaped lane separators (12) before the roundabout (2) are equipped with second speed sensors (13) to measure the speed of vehicles approaching the roundabout (2); these sensors are connected to a control unit (8) to automatically change the operating mode of the guiding lighted ring (6) and/or the warning light (10) when a speed higher than the permitted speed is measured.

10. A circular intersection according to claim 8, characterized in that the wedge- shaped lane separators (12) are equipped with additional warning lights (14), connected to a control unit (8) and/or to the first speed sensors (11) to signal the high speed of vehicles approaching the circular intersection (1).

11. A circular intersection according to at least one of claims 1 to 10, characterized in that in the area where the roadways (4, 4^', 5, 5^') connect to the roundabout (2), there are lighting fixtures (15) arranged to detect the arrival of a vehicle, and illuminating the respective part of the roadway (4, 4^', 5, 5^') and the roundabout (2) only during the passage of the vehicle through this part.

12. A circular intersection according to at least one of claims 1 to 11 , characterized in that it is equipped with at least one solar photovoltaic panel (16) for powering at least one device from the following group: highlighting and guiding lighted ring (6), warning light (10), control unit (8), speed sensors (11), additional warning light (14), lighting fixture (15).

13. A circular intersection according to claims 1 to 12, characterized in that it is equipped with a device (19) for actively transmitting a signal (20) containing information with a variable output directed towards approaching vehicles, while the device (19) is connected to a control unit (8).