Introduction The present invention relates to a reflector device for alerting about vehicles along a road, arranged to alert road travellers about vehicles on a curved road or at crossroads or at hilltops, where the visibility is limited or simply there is no sight due to obstacles along the road path, particularly because of topographic obstacles, or quite simply because the vehicle one may expect to encounter is outside the field of view.

Approach to the problem When travelling along a curved road or travelling on a road with hilltops, one will often have the terrain, forest or buildings that prevent from having direct line of sight to vehicles. It is not a condition of the invention that both parts shall have a vehicle, only that at least one party being on the road shall have a chance of observing light indirectly from an opposite party being on the road, where the opposite party has a light.

The second party moves towards or away from the first party, or is standing relatively still compared to the first party. However the below description is based on two mutually oncoming vehicles, both with headlights turned on, and both being able to see forward along the curved road. In the countries with obligatory headlights put on at day and night the invention is of use roughly all day and night, except in case of sharp sunlight. In other countries with no obligatory head lights regulation the invention has no effect until at least one of the parts uses the headlight, i.e. during the dusk or at night. Background art

It is known to arrange convex mirrors, , so-called traffic view mirrors, on posts near crossroads or sharp curves in such a way that one may get a strongly reduced but clear mirror image of oncoming or intersecting traffic. Such mirrors have significant advantages but it is difficult to estimate the distance to the oncoming traffic if one does not know the locality very well. The purpose of a such a traffic view mirror is generally to show a large portion of a road image and not necessarily only lights from an oncoming vehicle.

European patent application EP1475767 describes an apparatus comprised by a mirror reflector LED panel arranged by a road where there is no free sight between a first portion and an opposite second portion where the apparatus is placed between these portions. The apparatus may be used as a mirror in the day time and both mirror and road sign during night time, the mirror is connected to an electric motor and arranged to move in a desired direction. The mirror is arranged to be placed by sharp road curves so as for car drivers to be able to check whether there is light in the mirror, but also to a certain degree to alert their own presence along the way. The LED panel comprises solar cells and a battery arranged for being charged up. However the LED panel does not contribute to provide additional alert about oncoming traffic.

Japanese patent application 2007085150 describes an apparatus with a reflector device for traffic safety, for being arranged by a road where there is no free sight between a first portion and an opposite second portion. The apparatus is provided with at least to mirrors arranged for reflecting light between the portions.

US patent application US-6558010 describes a self- cleaning front glass on a traffic mirror arranged for being placed on a fence along the road. The US patent comprises solar cells and light emitting diodes.

The above mentioned traffic mirrors comprise batteries which require maintenance. In addition they do not comprise more than that single mirror which provides no significant indication of the distance to the oncoming vehicle.

Japanese international patent application WO 2004042151 describes a post with two mirrors essentially being convex in such a way that they are more convex in the vertical plane than in the horizontal plane, please see its Fig.11. In this way one obtains a quite wide-angle mirror in such a way that based on the position of the oncoming vehicle in the mirror image one may estimate the position of the oncoming vehicle relative to the mirror, please see its Fig.8. When two such mirrors are arranged in a vertical stack as shown in its Fig. 4 one may get an idea of the distance to the oncoming vehicles from the mirror. However, it is difficult to interpret mirror images in the dark. In addition it is difficult to interpret mirror images of the oncoming vehicle without its headlights turned on. A disadvantage of the Japanese international patent application is the relatively strong curvatures of the mirrors. This results in very weak reflected light if the source of incoming light is far away from the mirror, in this case light being reflected from far away is useless on long distances. Moreover, according to the invention it is of less interest to observe the mirror image of the oncoming vehicle as such, it is only of interest to observe the mirror image of its headlights.

Short summary of the invention

A solution to the above mentioned problems is a reflector device (1) for traffic safety arranged for being placed by a road (2) between a first portion (Pl) subdivided into two or more stretches of road (Al, A2 ) and an opposite second portion (P2) subdivided into two or more stretches of road (Bl, B2 ) where the distances between the reflector device (1) and the stretches of road (Al) and (Bl), respectively (A2) and (B2) generally corresponding to each other and being mutually without free sight, where the reflector device (1) for traffic safety comprises the following features:

- a first mirror (Ml) arranged for reflecting light from the first stretch of road(Al) along the first portion (Pl) to the first stretch of road (Bl) along the second portion (P2) and vice versa,

- a second mirror (M2) arranged for reflecting light from said second stretch of road(A2) along said first portion (Pl) to said second stretch of road(B2) along said second portion (P2) and vice versa,

- where the mirrors (Ml, M2 ) generally being plane or slightly convex, where the new features of the invention are:

- an index reflector (R) arranged for reflecting light from the first portion (Pl) back to the same, first portion (Pl), respectively light from said second portion (P2) back to the same, second portion (P2), and where the mirrors (Ml, M2 ) being arranged in different distances from the index reflector (R) .

An advantageous effect of the invention is that a first road traveller provided with a lamp and being along the first portion (Pl) of the road may estimate a distance to a second road traveller provided with a lamp and being along the second portion (P2) of the road relative to the reflector device (1), and vice versa.

According to a preferred embodiment the reflector device (1) according to the invention is adjusted and arranged in such a way that the opposite corresponding areas ((Al, Bl,), (A2, B2 ) , ..) have generally same distances from the position of the reflector device (1) as counted in normally estimated driving time. In this way the road travellers may expect to encounter each other by the reflector device (1) .

According to a second aspect of the invention it is a method for improving traffic safety of a road (2) by placing a reflector device (1) by the road, wherein the road (2) comprises a first portion (Pl) subdivided into two or more stretches of road (Al, A2) and an adjoining, opposite second portion (P2) subdivided into two or more stretches of road (Bl, B2 ) where the distances between the reflector device (1) and stretches of road (Al) and (Bl), (A2) and (B2) generally correspond to each other and being mutually without free sight,

- directing a first mirror (Ml) of the reflector device (1) in such a way that it reflects light from the first stretch of road (Al) along the first portion (Pl) to the first stretch of road (Bl) along the second portion (P2) and vice versa,

- directing a second mirror (M2) of the reflector device (1) arranged for reflecting light from the second stretch of road (A2) along the first portion (Pl) to the second stretch of road (B2) along the second portion (P2) and vice versa,

- said mirrors (Ml, M2 ) being generally plane or slightly convex, wherein the novelty of the invention is - arranging an index reflector (R) reflecting light from the first portion (Pl) back to the same, first portion (Pl), and light from the second portion (P2) back to the same, second portion (P2), respectively, and arranging the mirrors (Ml, M2 ) in different distances from the index reflector (R) .

Advantages of the invention

A first advantage of the invention is that an oncoming vehicle will generally be discerned in one of the mirrors (M) of the reflector device. In this way one will realize that there is a oncoming vehicle approximately at the same distance from the reflector device, but around the road curve or over the hilltop.

A second advantage of the invention is that due to having a desired sequence between the index reflector (R) and the mirrors (Ml, M2 ) , such as having the index reflector (R) arranged on the top of the post, just near the mirror which is arranged for reflecting between the most nearby portions of the road path relative to the reflector device. In such a way one may, by observing the separation between the index reflector and the mirror in which one observes the light from the oncoming vehicle , estimate the distance to the oncoming vehicle .

A third advantage of the invention is that it is totally passive, which means that it does not require energy nor maintenance other than repair in case of vandalism or cleaning when necessary.

Short figure captions

The invention is illustrated in the enclosed figures, wherein

Fig. 1 is a perspective view of a landscape with a curved road around a large hill on a tongue of land, with a first vehicle's headlights being visible on the road, and a second vehicle shown by broken lines, with the direct line of vision being blocked by the large hill. A post with a reflector device according to the invention is shown outermost in the road bend on the tongue of land.

Fig. 2 is a map sketch of the same area as shown in Fig.l. Corresponding opposite portions along the road on both sides of the post with a reflector device are shown so as for this to be arranged for reflecting light from the corresponding road portions respectively.

Fig. 3 is an image of a hilly area with a relatively straight stretch of road with a reflector device according to the invention. It is shown corresponding opposite portions along the road on both sides of the post with a reflector device so as for this being arranged to reflect light from the corresponding road portions respectively.

Fig.4 comprises sketches of an embodiment of a reflector device according to the invention. Fig. 4a is a perspective view of a post with the entire reflector device. Fig. 4b is a partial section, partial view of a mirror on the same reflector device. Fig 4c is an elevation view of a mirror of the same reflector device.

Description of preferred embodiments of the invention

In a simple embodiment of the invention a reflector post (1) along the road is put up. Such a post is illustrated in Fig. 4. A typical general situation is drafted in the perspective view in Fig. 1: a first vehicle (bl), in which we may imagine that we are placed, drives along a curved road outwards in the direction of a tongue of land where, according to the invention, a reflector device (1) is placed. By the tongue of the land the road sharply curves, and drawn using broken lines that indicate of an oncoming vehicle at the opposite portion of the road, around the tongue of the land. We refer to Figs.2 and 4 for the following description. The reflector post (1) comprises at least two mirrors (Ml, M2) arranged for reflecting light from a lamp (Ia) on the first vehicle (a) in direction towards the second vehicle (b) , so as for an observer (ob) in the second vehicle (b) to get a chance to see the reflected light from (a) via the reflector post (1) . The mirrors (Ml, M2, ...) are mainly plane or slightly convex in such a way that their reflected light do not disperse over an unnecessary large area, but being limited from one point by the one portion of the road to a quite limited area on the corresponding portion of the road. Oppositely, the same mirrors (Ml, M2 ) of the reflector post (1) will obviously function in such a way that they may reflect light from a lamp (Lb) on the second vehicle (b) heading towards the first vehicle (a) , so as for an observer (Oa) inside the first vehicle (a) will get a chance to see the reflected light from (b) via the reflector post (1) . The characteristic feature of the present invention is that the first mirror (Ml) is arranged to direct light from one first particular portion (Al) of a first part of the road through the first mirror (Ml) to a first particular opposite portion (Bl) of the road, and the second mirror (M2) is arranged to direct light from one second particular portion (Ai [2]) of the first part of the road via the second mirror (M2) to a second particular opposite portion (B2) of the road. In this way both parts may see the light reflected from each other and be aware of fact that they have a oncoming party on the road, without observing other than light from the oncoming vehicle. Furthermore, one may assume that one may encounter the oncoming party by the reflector device which is assumed to be placed there where the road has the smallest curve radius, i.e. where the road bends most sharply, and where the danger of unprepared passage is highest. This alerting may function on very long distance from the common reflector device. Furthermore, the characteristic of the present invention is that in one preferred end, preferably on the top of the reflector device (1) , an index reflector (R) is arranged generally for reflecting all light from the first portion (Pl), back to the first portion (Pl), or all light from the second portion (P2) back to the second portion (P2), or both. In this way each party may separately observe their own light reflected.

The seguence of mirrors (Ml, M2, ...) are arranged together with the index reflector (R) in such a way that each road traveller may see a mirror image in the (Ml, M2, ..) and a reflexion in the index reflector (R) with a systematically varying distance depending on the distance of the travellers from the reflector device (1) . In this way one may see that the reflection from the opposite party in the mirror (M) being displaced closer to the index reflector (R) as both travellers approach the reflector device (1) . If this is not observed as such, there is a possibility that the oncoming vehicle has come to a stop.

The actual reflector device may be designed in such a way that each mirror (Ml, M2,...) is provided with the an adjustment screw device (Sl, S2, ...) in such a way that the reflector device (1) with the mirror (Ml, M2, ...), when placed in the terrain, may be adjusted individually for being arranged for reflecting between those pairwise areas ((Al, Bl), (A2, B2) , ...) . The adjustment may be carried out by using laser target pointer or ordinary lamps placed out along the road.

Each adjustment screw device (Sl, S2, ...) may comprise two mainly orthogonally working adjustment screws ( (SIh, SIv) , (s2h, S2v) , ... ) arranged for adjusting the mirror both relative to horizontal and vertical angle arranged for reflecting between areas ((Al, Bl), (A2, B2 ) ) , each with their pairwise horizontal positions and differences of elevation.