US3399607A

US3399607A - Roadway surface marking, and marked road

Info

Publication number: US3399607A
Application number: US589288A
Authority: US
Inventors: Eigenmann Ludwig
Original assignee: CICOGNA FRANCO AND CO
Current assignee: CICOGNA FRANCO AND CO
Priority date: 1962-04-13
Filing date: 1966-10-25
Publication date: 1968-09-03
Anticipated expiration: 1985-09-03
Also published as: DE1784989A1; CH408983A; GB1032813A; DE1459813A1

Description

Sept. 3, 1968 I. eaezmnmu ROADIIAY SURFACE MARKING. AND MARKED ROAD Filed on. 25. 1 966 INVENT OR. is {a} A um EMJ. ow

United States Patent 5 Claims. (Cl. 94-1.s

This application is a continuation-in-part of application Ser. No. 262,658 filed Mar. 4, 1963.

This invention relates to the art of marking surfaces subject to mark-obliterating traffic, and more particularly to the marking of traflic lines and other directional data upon the pavement on streets and highways, by applying on and securing road marking tape material to said pavement.

Roadmarks consisting of tape or strip materiale are well known in the art, as being very advantageous in respect with conventional traflic aids, such as road-center lines, which are customarily painted upon the street or highway pavements with ordinary paints. The road-marking strip material is capable of resisting to the most severe traffic and its application to street and highway conventional surfaces requires little or no interruption to traflic. Such application can advantageously be made by making use of mechanical aids, such as the apparatus described and shown in my prior Patent No. 3,007,838.

The very scope of road marking is obviously to provide on the street or highway pavements signs and traflic data which have high daytime and nighttime visibility to motorists. Road-marking strip or tape materials as above considered can be compounded to provide traflic indicative high visibility surface portions on the marked road. The concept of high visibility is to be intended in its broadest meaning and cannot be definedas far as the invention is concernedin terms of brilliance and expressed by numerical values. Such traflic aids cannot be compared with a source of radiant energy, and are capable of reflecting ambient light only. Therefore, a high visibility surface portion, within the scope of this invention, Will hereinafter be termed high light reflectivity surface portion.

The character of high reflectivity is however at its turn difficult to define as, according to scope of the invention, an efliciently marked road is a road having a roadway surface and traffic regulating signs located thereon, said signs being such to be distinctly and clearly seen and neatly evidenced at distance by motorists, under the most different conditions of illumination. Many variables are involved in the visibility of road markings and of traflic conditions in general. The traflic occurs under bright sun light and in rainy Weather and dim ambient light, and at nighttime the roadway surface can be illuminated by powerful vehicle headlamps or by rather weak streetlamps, and therefore both intensity and direction of incident light are subject to the most wide variations.

As a matter of fact, one means for defining the visibility of a road marking or, more properly, the visibility of a traffic aid of the type considered on a roadway surface, is to compare the apparent brilliance of the road marking material considered, in several daytime and nighttime limit conditions, with the apparent brilliance of an identically shaped and positioned surface portion of a material of well known and measured reflectivity of visible light. A smooth surface of a layer of pure baryta (BaO) white may be assumed as a suitable basis of comparison. A road marking can be considered to have high reflectivity when, as photometrically compared as above with a simi- 3,399,607 Patented Sept. 3, 1968 larly shaped, located and illuminated sign of pure baryta, it is proved to have at least sixty percent apparent brilliance of said basis of comparison.

Therefore, the expression high reflectivity, anywhere hereinafter indicated as this description proceeds and in the appended claims, is intended to refer to a surface portion which, when photometrically compared with a surface portion of pure baryta white, it averages at least 60 percent apparent brilliance of its basis of comparison.

It has however been found that a marking tape material having the above or desirably better high reflectivity property does not possess the most desirable non-skid properties for ensuring the most desirable safe movement and control of fastly running vehicles, in particular when subject to intense positive or negative accelerations and/ or to centrifugal force. It is assumed that a roadway surface portion is non-skid when its adherence coefficient, with respect to current tired vehicles, averages the value of 40, in terms of angle to the horizontal at which a force corresponding to the weight applied to loaded tired wheel is directed to cause skidding of said wheel along the surface under test. The concepts of adherence offered by roadway surfaces and the modes for measuring same are well known in the art of roadway engineering and no further discussion is necessary thereabout.

It is therefore an object of this invention to provide a marked road which comprises a conventional surface for vehicles and a traflic aid consisting of tape material having both high light reflectivity and non-skid properties.

According to the invention, there is provided, on a conventional roadway surface, a compound tape material consisting of a first base strip having relatively non-skid properties and high light reflectivity, said base strip being adhesively adherent to said roadway surface, and strip components formed of a material having lesser light reflectivity than said first strip and non-skid properties, said strip components being aligned in longitudinal direction of the first strip and are adherent thereto equally spaced from the lateral edges of the first strip, whereby, on the surface of the road, a composite marking strip is formed having exposed portions formed by the first strip and having high light reflectivity and exposed center portions having non-skid properties.

By thus providing the strip with distinct portions of high light reflectivity and respectively of non-skid character, the well known disadvantages and limitations of conventional marked road are eliminated, inasmuch as the marked road according to the present invention will, in its marked surface portion, possess the most desirable high light reflectivity as well as higher non-skid properties than could be obtained up to now in combination with the desired degree of light reflectivity.

According to one embodiment of this invention, a strip formed of a material having non-skid properties and having a lesser width than said first high light reflective base strip is extended in longitudinal direction and adhered to said base strip equally spaced from the lateral edges thereof so as to provide a composite surface formed of two spaced edge portions of said first strip having high light reflectivity and of a center portion having non-skid properties and a lesser light reflectivity interposed between said two spaced edge portions of said first strip.

According to a modified embodiment of this invention, strip elements made of said material having non-skid properties are adhered to said base strip equally spaced from the lateral edges thereof and evenly spaced from each other in longitudinal direction.

It has been surprisingly found that the actual visibility of the traflic aid, in terms of clear and distinct detection thereof by motorists, is not appreciably reduced by the provision of non-skid portions of substantially lesser high light reflectivity on the whole marking surface, provided that the portion or portions having non-skid properties do not cover more than fifty percent of the area of said marking surface and that edge portions having high light reflectivity surfaces will uninterruptedly extend lengthwise the marking. As a matter of fact, the actual visibility, when considered as above, is apparently due to sharp reflectivity and color contrast with adjacent conventional roadway rather than amount of reflected radiations.

It has been further found that a surprising improvement of safe traffic and control of vehicles is attained by providing a marked road with a traflic aid having a compound surface as above, provided that at least twenty percent about of said surface of the marked area will possess non-skid properties.

These and other objects and advantages of the invention are in part obvious and in part will be made apparent as this description proceeds, and the features which are believed to be new and characteristic of the invention are in particular set forth in the appended claims. The invention itself, however, will be best understood from the following detailed description of preferred forms of em bodiment thereof, when taken in conjunction with the accompanying drawings, forming an essential component of this disclosure, and wherein:

FIGURE 1 is a diagrammatical perspective fragmentary view of a marked road according to first embodiment of the invention;

FIGURE 2 perspectively and diagrammatically illustrates how the compound strip material components can be preformed and assembled;

FIGURE 3 similarly illustrates a marked road according to a modified embodiment of the invention;

FIGURE 4 is a perspective exploded view of the compound material of FIG. 3; and

FIGURE 5 illustrates a further embodiment of the invention.

Referring more particularly to the drawings, FIG. 1 shows a specific method of forming and applying a road marking compound material to a road surface S to actuate a centre or a track-dividing line, for example, or other sign having a given transverse dimension W for visibility.

According to current knowledge, such transverse dimension W is however a great deal larger than the size which might theoretically give the required visibility, i.e. the ability of reflecting the desired amount of light, provided that the sign has a clean, smooth and undamaged upper face. Adverse weather and lighting conditions are obviously to be taken into account in dimensioning such trafiic regulation signs.

From another standpoint of view, however, there is a tendency to limit such transverse dimension within certain limits, six inches for example, because the currently elasto-plastic marking material have a more or less skidding upper face, on which vehicles tires may easily skid with consequent prejudice of safety. It is known that a road marking material is as much visible and lightreflecting as it is smooth and skidding. Smoothness of the light-reflecting upper face of such materials is also critical for preventing said face to become readily dirty and dark, and therefore poorly visible.

By dividing the whole transverse dimension W of the sign means total surface, which will be hereby and in the appended claims defined as marked area, in parts relatively coarse and non-skid and of relatively low visibility, and in parts of high reflectivity, said latter parts being adjacent to the marked area side edges, provided that the area of latter is at leasty fifty percent of the whole marked area, it has been found that the actual visibility of the sign will not substantially be prejudiced. It has been found that, at eyesight, clear visibility of such signs is essentially dependent on clear visibility of the side edge portions thereof.

Now, it might be assumed that the centre portion W wide of the marked area is not essential for improving "i 5 1 the visibility of the whole sign and, therefore, such centre portion W wide may be advantageouslymade such to possess improved non-skidding properties, essentially as an uncovered conventional road surface is. In addition, it might be assumed that the whole width W of the marking material may be increased with respect to the width of conventional elasto-plastic marking strips, as a consequence of the provision of the non-skid part W wide thereinto, the limit of such increment being given by the width of the portions designed for high light-reflection, individually considered.

According to what above, W is from 33 to 50 percent of W and W is of four inches or above, according to the size and importance and average traflic speed of the marked highway, according to current art of road marking, a W width over six inches being however preferred.

The compound strip of FIG. 1 consists of a first base strip 10 of high reflectivity material, lengthwise recessed at 12, and of a strip 14 of material having non-skid properties, seated into and firmly secured in the recessed portion of the base strip.

According to FIG. 3, the base strip has recessed portions 22 (FIG. 4) evenly spaced from the lateral edges thereof and wherein flat pieces 24 of non-skid properties possessing material are seated and secured in said recesses. Length L of individual pieces 24 may be comprised between 10 to 50 millimeters and the interval I therebetween may be comprised between 20 and 100 millimeters.

According to FIG. 5 two parallel longitudinal rows of pieces 34 spaced from each other and from the lateral edges of base strip are provided for imparting nonskid properties to the traflic aid, the number of such row and the dimensions of the pieces being matter of choice, provided that a firm connection of said pieces to said base strip is ensured to resist to traffic and to wear and shearing forces induced thereby.

Some examples of formulations and of compositions of components will be described hereinbelow for best understanding of the invention and of the differing modes for carrying out same.

Example 1 This example illustrates formulations and combinations particularly adapted for producing a compound marking material the type shown in FIG. 1, which includes two components, namely a first high reflectivity component and a second non-skid component/The respective compositions contents, expressed in terms of weight, will be indicated under HR (for High Reflectivity) and NS (for Non-Skid), respectively:

Content N-S Butadiene-acrylonitrile copolymer, having 38% acrylonitrile (acrylonitrilic rubber Chemigum No. 3, by Goodyear) 20 20 Maleic modified polyvlnyl-chloroacetate copoly'mer (Vinilite VMCH" by Union Carbide) 40 40 Mieromized calcium carbonate... 25 Talcum 0000 25 Zirconium oxide (average diameter .5 mils) Example 2 A marking material for providing a marked road of the type shown in FIGS. 3 and 5 have been produced from the following compositions, by weight:

High reflectivity base trip component:

Butadiene-acrylonitrile copolymer, having 38% acrylonitrile 12 Maleic modified polyvinyl chloroacetate copolymer 37 Titanium dioxide (rutile) 20 Kaolin 0000 25 Micromized calcium carbonate 28 Five parts of a suitable plastifier, such as a coumaronic resin, can be added. The compound is processed and laminated in strip form at 150 C.

Non-skid components:

Polychloroprene (such as Neoprene WHV The compound has been processed and laminated at 90 C., and the desired pieces have been cut therefrom. Such pieces have been applied and secured to the base strip component, at 90 C., by making use of a glue consisting of Glue:

85% styrene polymer-% butadiene polymer,

such as Marben 8000 A by Marbon Chemical 5 Clear natural rubber 5 Benzol 50 Dichloroethane 40 While the invention has been described and shown in few forms of embodiment thereof, it is obvious that the invention itself is not limited to the very details shown, and that further modifications and variations might be made thereto, according to the art.

What is claimed is:

1. A marked road, comprising in combination, a roadway surface for vehicles; a first strip of road marking tape having relatively low non-skid properties and high light reflectivity joined to the upper face of said roadway sur face; and another strip formed of a material having nonskid properties and a lesser light reflectivity than said first strip of road marking tape and having a lesser width than first strip extending in longitudinal direction and adhered to said first strip equally spaced from the lateral edges thereof so as to provide together with said first strip a composite surface formed of two spaced edge portions of said first strip of road marking tape having relatively low non-skid properties and high light reflectivity and of said other strip forming a center portion having non-skid properties and a lesser light reflectivity interposed between said two spaced edge portions of said first strip.

2. A marked road according to claim 1, wherein the width of said another strip is from one third to one half of the width of said first strip.

3. A marked road, comprising in combination, a roadway surface for vehicles; a first strip of road marking tape having relatively low non-skid properties and high light reflectivity adhesively joined to the upper face of said roadway surface; and strip components of a material having non-skid properties and a lesser light reflectivity than said first strip of road marking tape, said strip components being evenly spaced from each other and from the lateral edges of said first strip and adhered to said strip so as to provide together with said first strip a composite surface, longitudinally and laterally spaced portions of said first strip of road marking tape having high reflectivity and other portions spaced from said edges and having non-skid properties.

4. A marked road according to claim 3, wherein sum of the area of said portions having non-skid properties consists from twenty percent to fifty percent of the area defined between said lateral edges of first strip.

5. A marked road according to claim 3, wherein said portions having non-skid properties are arranged in a row of spaced elements equally spaced from the lateral edges of said first strip.

References Cited UNITED STATES PATENTS 2,225,496 12/1940 Gethin 94-l.5 2,898,825 8/1959 Walker 94-1.5 3,011,412 12/1961 Harrington 94--1.5 3,049,980 8/1962 Gill 941.5

NILE C. BYERS, Primary Examiner.

Claims

1. A MARKED ROAD, COMPRISING IN COMBINATION, A ROADWAY SURFACE FOR VEHICLES; A FIRST STRIP OF ROAD MARKING TAPE HAVING RELATIVELY LOW NON-SKID PROPERTIES AND HIGH LIGHT REFLECTIVELY JOINED TO THE UPPER FACE OF SAID ROADWAY SURFACE; AND ANOTHER STRIP FORMED OF A MATERIAL HAVING NONSKID PROPERTIES AND A LESSER LIGHT REFLECTIVITY THAN SAID FIRST STRIP OF ROAD MARKING TAPE AND HAVING A LESSER WIDTH THAN FIRST STRIP EXTENDING IN LONGITUDINAL DIRECTION AND ADHERED TO SAID FIRST STRIP EQUALLY SPACED FROM THE LATERAL EDGES THEREOF SO AS TO PROVIDE TOGETHER WITH SAID FIRST STRIP A COMPOSITE SURFACE FORMED OF TWO SPACED EDGE PORTIONS OF SAID FIRST STRIP OF ROAD MARKING TAPE HAVING RELATIVELY LOW NON-SKID PROPERTIES AND HIGH LIGHT REFLECTIVITY AND OF SAID OTHER STRIP FORMING A CENTER POSITION HAVING NON-SKID PROPERTIES AND A LESSER LIGHT REFLECTIVITY INTERPOSED BETWEEN SAID TWO SPACED EDGE PORTIONS OF SAID FIRST STRIP.