CN110322689A - A kind of visual domain model of expressway bend mark - Google Patents

Abstract

The invention discloses a kind of visual domain models of expressway bend mark, are defined first to mark visible range, propose visible range and be blocked judgment basis；Secondly geometrical model is constructed to the visual process of expressway bend mark, and derives the accounting equation of visible range；Finally Beijing-Hongkong Australia highway Hunan section has been carried out with the visual domain model created to calculate analysis, the result verification correctness and validity of model.The visual domain model of expressway bend mark of the invention provides design considerations for the setting of expressway bend mark, planting, highway expropriation of land range etc., for effectively solving the problems, such as that expressway bend mark visible range is blocked provides reference.

Description

A Visual Domain Model of Curve Signs on Expressway

technical field

The invention belongs to the technical field of highway engineering, and in particular relates to a visual domain model of an expressway curve sign.

Background technique

With the continuous development of expressway construction in our country, the mileage of highways has increased mainly in the mountainous areas in the west in recent years. Expressways in hilly areas are affected by complex terrain and landforms, and circular curves play a pivotal role in the alignment of expressways, thus forming many curves and most of them have blocked sightlines. Roadside plants, slopes, soundproof walls, etc. block signs, which have a certain impact on the recognition and reading of traffic signs, resulting in insufficient reading time for drivers, insufficient reading, and even wrong reading information, resulting in operating Mistakes or misjudgments can lead to traffic accidents such as rear-end collisions, rollovers, and collisions.

After summarizing and analyzing the domestic and foreign research on sign occlusion at curves, it is found that the current research on sign occlusion at bends at home and abroad has the following limitations: At present, most of the research on expressway traffic signs is devoted to sign occlusion. In terms of visibility, layout design, etc., there are still deficiencies based on the influence of occlusion on signs; there are many studies on the occlusion probability of signs by vehicles in the same direction, and some dynamic occlusion probability models have been established, but these occlusion models only solve the problem. The problem of vehicles in the same direction blocking the sign, and the sign is affected by many factors in the actual blocking process, such as the setting of the highway curve sign, planting, slope ratio of the roadside slope, and the location of the sound insulation wall, etc. lead to signs be blocked, and become a potential accident hazard.

Therefore, it is necessary to establish a dynamic model of the visual domain of curve markings to accurately represent the actual occlusion process, so as to propose corresponding solutions to the occlusion elements in the visual domain to reduce the occurrence of traffic accidents on curved road sections.

Contents of the invention

In view of the above problems, the present invention provides a visual domain model of expressway curve sign. The present invention studies the problem that the visual domain of the curve sign on the expressway is blocked. First, the visual domain of the sign is defined, and the basis for judging the occlusion is proposed; secondly, a geometric model is constructed for the visual process of the curve mark on the expressway, and The calculation equation of the visual domain is deduced; finally, the calculation and analysis of the Hunan section of the Beijing-Hong Kong-Macau Expressway is carried out with the created visual domain model, and the results verify the correctness and effectiveness of the model.

The present invention is realized through the following technical solutions:

A highway curve sign visual area model, the volume calculation equation of the expressway curve sign visual area is:

In the formula,

a: the length of the sign, in m;

b: the width of the sign, in m;

R: the radius distance from the center of the curve circle to the sign, in m;

r: the radius distance from the center of the curve circle to the car, in m;

β: The angle between the straight line from the mark to the center of the curve circle and the positive X axis;

v: vehicle speed, unit km/h;

t _i : the time from the initial reading point B to the vanishing point E to read the sign.

The construction of the highway curve sign visual domain model of the present invention comprises the following steps:

(1) Analyze the sign situation of the place where the bend accident occurred, and analyze the factors that the visual field of the bend sign is blocked from various aspects.

(2) Define the visual area of the sign: According to the analysis of the process of recognizing and reading the traffic sign in the "Handbook of Highway Traffic Signs and Markings" (JTGD82-2009), the process of recognizing and reading the curve sign is shown in Figure 1, where A B is the starting point of reading, C is the point of finishing reading, D is the point of action, E is the point of disappearance, S is the mark, and F is the point of completion of action.

Usually, the driver in the driving vehicle has found the sign S at point A, starts to read the content of the sign at point B, and can fully obtain the sign information at point C, which is called distance To read the distance; after reading the sign, the driver will take actions to judge within the distance between point C and point D, which is called distance In order to judge the distance; finally, the driver starts to act from point D until the action of point F is completed, which is called the distance is the action distance; the distance from point B to the sign S is called the visual distance When the driver approaches the sign during driving, the distance from the area where the sign cannot be seen due to the angle and the blind spot of the field of vision to the sign S is called the vanishing distance The distance from point C to sign S after reading is

if distance ratio The distance is short, and the vanishing point E appears before point C is read, which will result in insufficient sign recognition time, and the driver cannot accurately interpret the sign content. if Then the point C after reading coincides with the vanishing point E, which is the limit value of sign recognition and reading. In order to provide a tolerant sign recognition and reading time, it is assumed that the visible area of the sign in the present invention is blocked At the same time, from the starting reading point B to the vanishing point E, no obstructions can appear in the sight corridor of reading signs. Therefore, the present invention defines the sign visual field process as the reading distance According to Figure 1, there are:

In the formula, To read the distance, that is, the driver starts to read the content of the sign at point B, and can fully obtain the sign information at point C;

is the distance from point C to sign S after reading;

is the vanishing distance, that is, the distance from the vanishing point E to the sign S;

Assuming the car is traveling at a constant speed, then

In the formula:

v: vehicle speed, unit km/h;

t: reading time, that is, the time required to read the sign, unit s;

In the formula:

5.67 is obtained from the experimental results of the Japanese Civil Engineering Research Institute;

h ^* : effective character height on the logo, unit m;

In the formula:

H: The setting height of the sign, that is, the height from the ground to the bottom of the sign, in m;

h: driver's apparent height, unit m;

θ: Vanishing angle, that is, the angle between the vanishing point and the mark;

Substituting formula (1-2), (1-3) and (1-4) into formula (1-1), we have:

In the formula:

v: vehicle speed, unit km/h;

t: reading time, that is, the time required to read the sign, unit s;

h ^* : effective character height on the logo, unit m;

H: The setting height of the sign, that is, the height from the ground to the bottom of the sign, in m;

h: driver's apparent height, unit m;

θ: Vanishing angle, that is, the angle between the vanishing point and the mark.

(3) Construct a geometric model for the visual process of expressway curve signs:

Establish a space Cartesian coordinate system: take the center of the curved circular curve as the origin, take the line from the center of the circle to the starting reading point B as the X-axis, establish the X-axis in the positive direction, and the Y-axis is perpendicular to the X-axis, and the positive direction of the Y-axis is the starting point Read the direction from point B to mark S, and the Z axis is vertically upward;

Make the visual domain model of the highway curve sign, as shown in Figure 2;

Make a cross-sectional view of the highway curve sign visual domain, as shown in Figure 3;

It can be seen from Figure 3 that the vertical height h ₁ from the center of the sign to the ground = H+b/2...(1-6),

The vertical height h ₂ from the center of the sign to the driver's sight height = H+b/2-h...(1-7),

In the formula,

H: The setting height of the sign, that is, the height from the ground to the bottom of the sign, in m;

b: the width of the sign, in m;

h: driver's apparent height, unit m;

It can be seen from Figure 2 and Figure 3 that the spatial coordinates of the logo are (Rcosβ, Rsinβ, H+b/2)...(1-8)

In the formula,

R: the radius distance from the center of the curve circle to the sign, in m;

β: The angle between the straight line from the mark to the center of the curve circle and the positive X axis;

H: The setting height of the sign, that is, the height from the ground to the bottom of the sign, in m;

b: the width of the sign, in m;

According to Figure 3, it can be known from the Pythagorean theorem,

According to Figure 2, it can be seen from the relationship between the sides and angles of the triangle that d ² =R ² +r ² -2Rrcosβ...(1-10)

so

In the formula,

d: the horizontal distance from the driver's apparent height to the sign, in m;

L: the distance from the driver's apparent height to the center of the sign, in m;

H: the height from the ground to the bottom of the sign, in m;

b: the width of the sign, in m;

h: driver's apparent height, unit m;

R: the radius distance from the center of the curve circle to the sign, in m;

r: the radius distance from the center of the curve circle to the car, in m;

β: The angle between the straight line from the mark to the center of the curve circle and the positive X axis;

After passing the starting reading point B, the driver does not take any action, and the speed of the car remains unchanged, then the arc distance Z=vt _i traveled by the car during the process from the starting reading point B to the vanishing point E...(1- 12)

In the formula,

v: vehicle speed, unit km/h;

t _i : the time from the start reading point B to the vanishing point E to recognize and read the sign;

According to the calculation formula of the arc, it can be known that the angle that the car turns relative to the positive X axis when driving from the starting point B to the vanishing point E

In the formula,

Z: The arc distance traveled by the car from the starting point B to the vanishing point E, in m;

r: the radius distance from the center of the curve circle to the car, in m;

Substituting formula (1-12) into formula (1-13), we have:

In the formula:

α: The angle that the car has turned relative to the positive X axis when it is driving from the starting point B to the vanishing point E;

v: vehicle speed, unit km/h;

t _i : the time from the start reading point B to the vanishing point E to recognize and read the sign;

r: the radius distance from the center of the curve circle to the car, in m;

When the car is driving from the starting point B to the vanishing point E, the distance from the driver's apparent height to the sign is:

Ⅰ. At the starting point B, the distance from the driver's apparent height to the sign

In the formula,

v: vehicle speed, unit km/h;

t: reading time, that is, the time required to read the sign, unit s;

5.67 is obtained from the experimental results of the Japanese Civil Engineering Research Institute;

h ^* : effective character height on the logo, unit m;

Ⅱ. Between the starting point B and the vanishing point E: According to Figure 2 and Figure 3, the spatial coordinates of the driver's apparent height are (rcosα, rsinα, h)...(1-16)

In the formula,

r: the radius distance from the center of the curve circle to the car, in m;

α: The angle that the car has turned relative to the positive X axis when it is driving from the starting point B to the vanishing point E;

h: driver's apparent height, unit m;

According to formula (1-8) and formula (1-16), the distance from the driver's apparent height to the sign

Substituting formula (1-14) into formula (1-17) has:

In the formula:

R: the radius distance from the center of the curve circle to the sign, in m;

r: the radius distance from the center of the curve circle to the car, in m;

β: The angle between the straight line from the mark to the center of the curve circle and the positive X axis;

v: vehicle speed, unit km/h;

t _i : the time from the start reading point B to the vanishing point E to recognize and read the sign;

H: the height from the ground to the bottom of the sign, in m;

b: the width of the sign, in m;

h: driver's apparent height, unit m;

During the driving process of the car from the starting point B to the vanishing point E, the volume of the quadrangular pyramid space formed by the driver's apparent height to the sign: V _i =1/3abd...(1-19)

In the formula,

a: the length of the sign, in m;

b: the width of the sign, in m;

d: the horizontal distance from the driver's apparent height to the sign, in m;

According to formula (1-8) and formula (1-16),

In the formula,

d: the horizontal distance from the driver's apparent height to the sign, in m;

R: the radius distance from the center of the curve circle to the sign, in m;

r: the radius distance from the center of the curve circle to the car, in m;

α: The angle that the car has turned relative to the positive X axis when it is driving from the starting point B to the vanishing point E;

β: The angle between the straight line from the mark to the center of the curve circle and the positive X axis;

Substituting formula (1-20) into formula (1-19), we get

In the formula,

a: the length of the sign, in m;

b: the width of the sign, in m;

R: the radius distance from the center of the curve circle to the sign, in m;

r: the radius distance from the center of the curve circle to the car, in m;

α: The angle that the car has turned relative to the positive X axis when it is driving from the starting point B to the vanishing point E;

β: The angle between the straight line from the mark to the center of the curve circle and the positive X axis;

Substituting formula (1-14) into formula (1-21), we get

In the formula,

a: the length of the sign, in m;

b: the width of the sign, in m;

R: the radius distance from the center of the curve circle to the sign, in m;

r: the radius distance from the center of the curve circle to the car, in m;

β: The angle between the straight line from the mark to the center of the curve circle and the positive X axis;

v: vehicle speed, unit km/h;

t _i : the time from the initial reading point B to the vanishing point E to read the sign.

As a preferred technical solution, the sign is a roadside sign or a suspended sign.

Compared with prior art, advantage and beneficial effect of the present invention are:

(1) The model of the present invention fully considers the influence of factors such as curves, cars, signs, etc., and the visual domain model established is a dynamic model, which can more accurately describe the visual domain of the signs at the curve, and use it for Beijing-Hong Kong-Macao Expressway The Hunan section of the highway was calculated and analyzed, and the results verified the correctness and effectiveness of the model.

(2) the calculation method of the present invention can calculate the visual field area of each freeway curve section different radius, the relation between driving speed and the visual field, the faster the visual field changes the faster the driving speed, based on this It can provide design basis for the setting of highway curve signs, plant planting, road land acquisition range, etc. It is also suitable for highway design planning and safety management, and provides a solution for effectively solving the problem that the visual field of highway curve signs in hilly areas is blocked. refer to.

Description of drawings

Fig. 1 is a schematic diagram of the recognition and reading process of the curve marking in the present invention.

Fig. 2 is a schematic diagram of the visual domain model of the curve sign of the present invention, in the figure, a: the length of the sign, in m; b: the width of the sign, in m; H: the setting height of the sign, that is, the distance from the ground to the bottom of the sign Height, unit m; h: driver’s apparent height, unit m; R: radius distance from the center of the curve curve to the sign, unit m; r: radius distance from the center of the curve curve to the car, unit m; α: The angle that the car turns relative to the positive X-axis when driving from the starting point B to the vanishing point E; β: the angle between the straight line from the mark to the center of the curve circle and the positive X-axis; L ₀ : at the starting point B , the distance from the driver's apparent height to the sign, in m; V _i : the space volume of the quadrangular pyramid formed by the driver's apparent height to the sign when the car is driving from the starting point B to the vanishing point E, in m ³ .

Fig. 3 is a schematic cross-sectional view of the visible area of the curve sign of the present invention; in the figure, a: the length of the sign, in m; b: the width of the sign, in m; H: the setting height of the sign, that is, the height from the ground to the bottom of the sign , unit m; h ₁ : vertical height from the center of the sign to the ground, unit m; h ₂ : vertical height from the center of the sign to the driver’s sight height, unit m; h: driver’s sight height, unit m; θ: vanishing angle , that is, the angle between the vanishing point and the sign; d: the horizontal distance from the driver’s sight height to the sign, in m; L _i : the distance from the driver’s sight height to the center of the sign when the car is driving from the starting reading point B to the vanishing point E Point distance, unit m.

Figure 4 Schematic diagram of the main sections of the Hunan section of the Beijing-Hong Kong-Macao Expressway.

Fig. 5 is a diagram showing the variation of the visible area of the concave curve.

Fig. 6 is a simulation diagram of the visible domain of the concave curve.

Fig. 7 is a graph showing the variation of the visible area of a convex curve.

Fig. 8 is a simulation diagram of the visual domain of the convex curve.

Detailed ways

The present invention will be described in further detail below in conjunction with specific embodiments and accompanying drawings, but is not limited to the protection scope of the present invention.

Example 1

A highway curve sign visual area model, the volume calculation equation of the expressway curve sign visual area is:

In the formula,

a: the length of the sign, in m;

b: the width of the sign, in m;

R: the radius distance from the center of the curve circle to the sign, in m;

r: the radius distance from the center of the curve circle to the car, in m;

β: The angle between the straight line from the mark to the center of the curve circle and the positive X axis;

v: vehicle speed, unit km/h;

t _i : the time to read the sign from the initial reading point B to the vanishing point E, according to the driver's reading speed, the value range of this research is 2-3s.

The construction of the highway curve sign visual domain model of the present invention comprises the following steps:

(1) Analyze the sign situation of the place where the bend accident occurred, and analyze the factors that the visual field of the bend sign is blocked from various aspects.

(2) Define the visual area of the sign: According to the analysis of the process of recognizing and reading the traffic sign in the "Handbook of Highway Traffic Signs and Markings" (JTGD82-2009), the process of recognizing and reading the curve sign is shown in Figure 1, where A B is the starting point of reading, C is the point of finishing reading, D is the point of action, E is the point of disappearance, S is the mark, and F is the point of completion of action.

Usually, the driver in the driving vehicle has found the sign S at point A, starts to read the content of the sign at point B, and can fully obtain the sign information at point C, which is called distance To read the distance; after reading the sign, the driver will take actions to judge within the distance between point C and point D, which is called distance In order to judge the distance; finally, the driver starts to act from point D until the action of point F is completed, which is called the distance is the action distance; the distance from point B to the sign S is called the visual distance When the driver approaches the sign during driving, the distance from the area where the sign cannot be seen due to the angle and the blind spot of the field of vision to the sign S is called the vanishing distance The distance from point C to sign S after reading is

if distance ratio The distance is short, and the vanishing point E appears before point C is read, which will result in insufficient sign recognition time, and the driver cannot accurately interpret the sign content. if Then the point C after reading coincides with the vanishing point E, which is the limit value of sign recognition and reading. In order to provide a tolerant sign recognition and reading time, it is assumed that the visible area of the sign in the present invention is blocked At the same time, from the starting reading point B to the vanishing point E, no obstructions can appear in the sight corridor of reading signs. Therefore, the present invention defines the sign visual field process as the reading distance According to Figure 1, there are:

In the formula, To read the distance, that is, the driver starts to read the content of the sign at point B, and can fully obtain the sign information at point C;

is the distance from point C to sign S after reading;

is the vanishing distance, that is, the distance from the vanishing point E to the sign S;

Assuming the car is traveling at a constant speed, then

In the formula:

v: vehicle speed, unit km/h;

t: recognition time, that is, the time required to recognize and read signs, in s; according to the driver’s recognition speed, the value is generally 2-3s, and the average recognition speed of the driver is 2.5s in this study;

In the formula:

5.67 is obtained from the experimental results of the Japanese Civil Engineering Research Institute;

h ^* : effective character height on the logo, unit m;

In the formula:

H: The setting height of the sign, that is, the height from the ground to the bottom of the sign, in m;

h: driver's apparent height, unit m; general research value is 1.2m;

θ: Vanishing angle, that is, the angle between the vanishing point and the sign; generally, the roadside sign takes 15°, and the elevation angle of the suspended sign from the vanishing point to the top edge of the sign is 7°;

Substituting formula (1-2), (1-3) and (1-4) into formula (1-1), we have:

In the formula:

v: vehicle speed, unit km/h;

t: recognition time, that is, the time required to recognize and read signs, in s; according to the driver’s recognition speed, the value is generally 2-3s, and the average recognition speed of the driver is 2.5s in this study;

h ^* : effective character height on the logo, unit m;

H: The setting height of the sign, that is, the height from the ground to the bottom of the sign, in m;

h: driver's apparent height, unit m; general research value is 1.2m;

θ: Vanishing angle, that is, the angle between the vanishing point and the sign; generally, the roadside sign takes 15°, and the elevation angle of the suspended sign from the vanishing point to the top edge of the sign is 7°.

(3) Construct a geometric model for the visual process of expressway curve signs:

Establish a space Cartesian coordinate system: take the center of the curved circle curve as the origin, take the line from the center of the circle to the starting reading point B as the X-axis, establish the X-axis in the positive direction, and the Y-axis is perpendicular to the X-axis, and the positive direction of the Y-axis is the starting point Read the direction from point B to mark S, and the Z axis is vertically upward;

Make the visual domain model of the highway curve sign, as shown in Figure 2;

Make a cross-sectional view of the highway curve sign visual domain, as shown in Figure 3;

It can be seen from Figure 3 that the vertical height h ₁ from the center of the sign to the ground = H+b/2...(1-6),

The vertical height h ₂ from the center of the sign to the driver's sight height = H+b/2-h...(1-7),

In the formula,

H: The setting height of the sign, that is, the height from the ground to the bottom of the sign, in m;

b: the width of the sign, in m;

h: driver's apparent height, unit m; general research value is 1.2m;

It can be seen from Figure 2 and Figure 3 that the spatial coordinates of the logo are (Rcosβ, Rsinβ, H+b/2)...(1-8)

In the formula,

R: the radius distance from the center of the curve circle to the sign, in m;

β: The angle between the straight line from the mark to the center of the curve circle and the positive X axis;

H: The setting height of the sign, that is, the height from the ground to the bottom of the sign, in m;

b: the width of the sign, in m;

According to Figure 3, it can be known from the Pythagorean theorem,

According to Figure 2, it can be seen from the relationship between the sides and angles of the triangle that d ² =R ² +r ² -2Rrcosβ...(1-10)

so

In the formula,

d: the horizontal distance from the driver's apparent height to the sign, in m;

L: the distance from the driver's apparent height to the center of the sign, in m;

H: the height from the ground to the bottom of the sign, in m;

b: the width of the sign, in m;

h: driver's apparent height, unit m; general research value is 1.2m;

R: the radius distance from the center of the curve circle to the sign, in m;

r: the radius distance from the center of the curve circle to the car, in m;

β: The angle between the straight line from the mark to the center of the curve circle and the positive X axis;

After passing the starting reading point B, the driver does not take any action, and the speed of the car remains unchanged, then the arc distance Z=vt _i traveled by the car during the process from the starting reading point B to the vanishing point E...(1- 12)

In the formula,

v: vehicle speed, unit km/h;

t _i : the time to read the sign from the initial reading point B to the vanishing point E, according to the driver's reading speed, the value range of this research is 2-3s;

According to the calculation formula of the arc, it can be known that the angle that the car turns relative to the positive X axis when driving from the starting point B to the vanishing point E

In the formula,

Z: The arc distance traveled by the car from the starting point B to the vanishing point E, in m;

r: the radius distance from the center of the curve circle to the car, in m;

Substituting formula (1-12) into formula (1-13), we have:

In the formula:

α: The angle that the car has turned relative to the positive X axis when it is driving from the starting point B to the vanishing point E;

v: vehicle speed, unit km/h;

t _i : the time to read the sign from the initial reading point B to the vanishing point E, according to the driver's reading speed, the value range of this research is 2-3s;

r: the radius distance from the center of the curve circle to the car, in m;

When the car is driving from the starting point B to the vanishing point E, the distance from the driver's apparent height to the sign is:

Ⅰ. At the starting point B, the distance from the driver's apparent height to the sign

In the formula,

v: vehicle speed, unit km/h;

t: recognition time, that is, the time required to recognize and read signs, in s; according to the driver’s recognition speed, the value is generally 2-3s, and the average recognition speed of the driver is 2.5s in this study;

5.67 is obtained from the experimental results of the Japanese Civil Engineering Research Institute;

h ^* : effective character height on the logo, unit m;

Ⅱ. Between the starting point B and the vanishing point E: According to Figure 2 and Figure 3, the spatial coordinates of the driver's apparent height are (rcosα, rsinα, h)...(1-16)

In the formula,

r: the radius distance from the center of the curve circle to the car, in m;

α: The angle that the car has turned relative to the positive X axis when it is driving from the starting point B to the vanishing point E;

h: driver's apparent height, unit m; general research value is 1.2m;

According to formula (1-8) and formula (1-16), the distance from the driver's apparent height to the sign

Substituting formula (1-14) into formula (1-17) has:

In the formula:

R: the radius distance from the center of the curve circle to the sign, in m;

r: the radius distance from the center of the curve circle to the car, in m;

β: The angle between the straight line from the mark to the center of the curve circle and the positive X axis;

v: vehicle speed, unit km/h;

t _i : the time to read the sign from the initial reading point B to the vanishing point E, according to the driver's reading speed, the value range of this research is 2-3s;

H: the height from the ground to the bottom of the sign, in m;

b: the width of the sign, in m;

h: driver's apparent height, unit m; general research value is 1.2m;

When the car is driving from the starting point B to the vanishing point E, the space volume of the quadrangular pyramid formed by the driver's apparent height to the sign:

V _i =1/3abd...(1-19)

In the formula,

a: the length of the sign, in m;

b: the width of the sign, in m;

d: the horizontal distance from the driver's apparent height to the sign, in m;

According to formula (1-8) and formula (1-16),

In the formula,

d: the horizontal distance from the driver's apparent height to the sign, in m;

R: the radius distance from the center of the curve circle to the sign, in m;

r: the radius distance from the center of the curve circle to the car, in m;

α: The angle that the car has turned relative to the positive X axis when it is driving from the starting point B to the vanishing point E;

β: The angle between the straight line from the mark to the center of the curve circle and the positive X axis;

Substituting formula (1-20) into formula (1-19), we get

In the formula,

a: the length of the sign, in m;

b: the width of the sign, in m;

R: the radius distance from the center of the curve circle to the sign, in m;

r: the radius distance from the center of the curve circle to the car, in m;

α: The angle that the car has turned relative to the positive X axis when it is driving from the starting point B to the vanishing point E;

β: The angle between the straight line from the mark to the center of the curve circle and the positive X axis;

Substituting formula (1-14) into formula (1-21), we get

In the formula,

a: the length of the sign, in m;

b: the width of the sign, in m;

R: the radius distance from the center of the curved curve to the sign, in m;

r: the radius distance from the center of the curve circle to the car, in m;

β: The angle between the straight line from the mark to the center of the curve circle and the positive X axis;

v: vehicle speed, unit km/h;

t _i : the time to read the sign from the initial reading point B to the vanishing point E, according to the driver's reading speed, the value range of this research is 2-3s.

(4) Verify the correctness and validity of the model, including:

① Collect relevant information on the Hunan section of the Beijing-Hong Kong-Macao Expressway:

The main section of the Hunan section of the Beijing-Hong Kong-Macao Expressway is shown in Figure 4, with a width of 28m, two driving lanes of 3.75m, and a central divider of 4.5m.

② Only the radius of the circular curve is considered for the curve in the checking calculation, and the general value of the minimum radius of the circular curve in the "Code for Design of Highway Routes" (JTG D20-2006) is used for checking calculation, which is divided into two types: concave curve and convex curve. The general values of the minimum radius of the circular curve are shown in Table 1:

Table 1 General values of the minimum radius of circular curves

Design speed (km/h) 120 100 80 60 40 The general value of the minimum radius of the circular curve (m) 1000 700 400 200 100

③ Sign related parameters:

The sign selects the cantilever signboard, the length a is 4.8m, the width b is 3m, and the setting height H is 5.2m.

④Visible area check of roadside signs at the bend of Hunan Section of Beijing-Hong Kong-Macau Expressway:

Through matlab modeling, the relevant parameters are substituted into the volume calculation equation of the visible area of the highway curve sign:

In the formula: a is 4.8m, b is 3m, R=r=the general value of the minimum radius of the circular curve.

The occlusion volume of the sign at different speeds is simulated. The change diagram of the visible area of the concave curve is shown in Figure 5, and the simulation diagram of the visible area of the concave curve is shown in Figure 6.

It can be seen from Figure 5 that the volume of the visible area of the sign ^on the concave curve is between 600m3 and 1000m3. With the change ^of driving time, the volume of the visible area of the sign decreases linearly. The closer to the sign, it can be affected by occlusion less visible area. With different driving speeds and different radiuses of circular curves, the slower the driving speed, the slower the change of the visual domain affected by occlusion, and the faster the driving speed, the greater the change of the visual domain affected by occlusion.

It can be seen from Figure 6 that the concave curve is easily blocked by elements such as roadside plants, slopes, and vehicles traveling on the right side.

The volume of the visible area of the sign at different speeds is simulated. The change diagram of the visible area affected by the occlusion of the convex curve is shown in Figure 7, and the simulation diagram of the visible area affected by the occlusion of the convex curve is shown in Figure 8.

It can be seen from Figure 7 that the volume of the visible area of the sign ^on the convex curve is between 600m3 and 1000m3. With the change ^of driving time, the volume of the visible area of the sign decreases linearly. The closer to the sign, it can be affected by occlusion less visible area. With different driving speeds and different radiuses of circular curves, the slower the driving speed, the slower the change of the visual domain affected by occlusion, and the faster the driving speed, the greater the change of the visual domain affected by occlusion.

It can be seen from Figure 8 that the convex curve is easily blocked by elements such as the mid-section belt and overpass bridge.

Claims (3)

1. a kind of visual domain model of expressway bend mark, which is characterized in that the expressway bend mark of the model is visual The volume accounting equation in domain are as follows:

In formula,

A: the length of mark, unit m；

B: the width of mark, unit m；

R: radius distance of the bend circular curve center of circle to mark, unit m；

R: the radius distance in the bend circular curve center of circle to automobile, unit m；

β: the straight line of mark to the bend circular curve center of circle and the angle of positive X-axis；

V: automobile driving speed, unit km/h；

t_i: the time for reading mark is recognized from beginning read point B to end point E.

2. the visual domain model of expressway bend mark according to claim 1, which is characterized in that the building of the model The following steps are included:

(1) the mark situation of the bend accident spot occurred is analyzed, analyzes curve sign visible range quilt from every side The factor blocked；

(2) mark visible range is defined: according to friendship in " handbook is arranged in highway traffic sign and graticule " (JTGD82-2009) Logical mark recognizes read procedure analysis, and curve sign recognizes read procedure as shown in Figure 1, wherein A is depending on recognizing a little, and B is beginning read point, and C is to read Fixed point, D are action limit, and E is end point, and S is mark, and F is that point is completed in movement；

The present invention will indicate that visible range process is set to and recognize reading distanceAccording to Fig. 1, have:

In formula,To read distance, i.e. driver starts to read logo content at B point, can flag information is complete to C point It is complete to obtain；

For the distance for running through point C to mark S；

For disappearance distance, i.e. distance of the end point E to mark S；

Assuming that automobile drives at a constant speed, then

In formula:

V: automobile driving speed, unit km/h；

T: recognizing read time, that is, recognizes time needed for reading mark, unit s；

In formula:

Obtained by 5.67 experimental result for Japanese building research institute；

h^*: significant character height on mark, unit m；

In formula:

H: the height of the setting height of mark, i.e. ground to mark bottom, unit m；

H: the view of driver is high, unit m；

θ: the angle at disappearance angle, i.e. end point and mark；

Formula (1-2), (1-3) and (1-4) is substituted into formula (1-1), is had:

In formula:

V: automobile driving speed, unit km/h；

T: recognizing read time, that is, recognizes time needed for reading mark, unit s；

h^*: significant character height on mark, unit m；

H: the height of the setting height of mark, i.e. ground to mark bottom, unit m；

H: the view of driver is high, unit m；

θ: the angle at disappearance angle, i.e. end point and mark；

(3) geometrical model is constructed to the visual process of expressway bend mark:

Establish rectangular coordinate system in space: using the center of circle of bend circular curve as origin, using the line in the center of circle to beginning read point B as X-axis, just To X-axis is established, Y-axis is perpendicular to X-axis, and Y-axis forward direction is beginning read point B to the direction of mark S, and Z axis is upward perpendicular to the ground；

Make the visual domain model of expressway bend mark, as shown in Figure 2；

Make expressway bend mark visible range cross-section diagram, as shown in Figure 3；

From the figure 3, it may be seen that vertical height h of the mark center to ground₁=H+b/2 ... (1-6),

Mark center regards high vertical height h to driver₂=H+b/2-h ... (1-7),

In formula,

H: the height of the setting height of mark, i.e. ground to mark bottom, unit m；

B: the width of mark, unit m；

H: the view of driver is high, unit m；

By Fig. 2 and Fig. 3 it is found that the space coordinate of mark is (Rcos β, Rsin β, H+b/2) ... (1-8)

In formula,

R: radius distance of the bend circular curve center of circle to mark, unit m；

β: the straight line of mark to the bend circular curve center of circle and the angle of positive X-axis；

H: the height of the setting height of mark, i.e. ground to mark bottom, unit m；

B: the width of mark, unit m；

According to Fig. 3, by Pythagorean theorem it is found that

According to fig. 2, by the corner relationship of triangle it is found that d²=R²+r²-2Rrcosβ……(1-10)

So

In formula,

D: driver regards the high horizontal distance to mark, unit m；

L: the high distance to mark central point of the view of driver, unit m；

H: height of the ground to mark bottom, unit m；

B: the width of mark, unit m；

H: the view of driver is high, unit m；

R: radius distance of the bend circular curve center of circle to mark, unit m；

R: the radius distance in the bend circular curve center of circle to automobile, unit m；

β: the straight line of mark to the bend circular curve center of circle and the angle of positive X-axis；

After beginning read point B, driver does not take action, and the speed of automobile remains unchanged, then automobile from beginning read point B to The camber line distance Z=v.t travelled during end point E_i……(1-12)

In formula,

V: automobile driving speed, unit km/h；

t_i: the time for reading mark is recognized from beginning read point B to end point E；

According to the radian calculation formula of circular arc it is found that automobile is turned over relative to positive X-axis when driving from beginning read point B to end point E Angle

In formula,

Z: the camber line distance that automobile travels during from beginning read point B to end point E, unit m；

R: the radius distance in the bend circular curve center of circle to automobile, unit m；

Formula (1-12) is substituted into formula (1-13), is had:

In formula:

α: the angle that automobile is turned over relative to positive X-axis from beginning read point B to end point E when driving；

V: automobile driving speed, unit km/h；

t_i: the time for reading mark is recognized from beginning read point B to end point E；

R: the radius distance in the bend circular curve center of circle to automobile, unit m；

Automobile is from beginning read point B, into end point E driving process, driver has depending on high to the distance indicated:

For I, in beginning read point B, driver regards the high distance to mark

In formula,

V: automobile driving speed, unit km/h；

T: recognizing read time, that is, recognizes time needed for reading mark, unit s；

Obtained by 5.67 experimental result for Japanese building research institute；

h^*: significant character height on mark, unit m；

II, is between beginning read point B to end point E: according to fig. 2 with Fig. 3 it is found that driver regard high space coordinate as (rcos α, rsinα,h)……(1-16)

In formula,

R: the radius distance in the bend circular curve center of circle to automobile, unit m；

α: the angle that automobile is turned over relative to positive X-axis from beginning read point B to end point E when driving；

H: the view of driver is high, unit m；

Known by formula (1-8) and formula (1-16), driver regards the high distance to mark

Formula (1-14) substitution formula (1-17) is had:

In formula:

R: radius distance of the bend circular curve center of circle to mark, unit m；

R: the radius distance in the bend circular curve center of circle to automobile, unit m；

β: the straight line of mark to the bend circular curve center of circle and the angle of positive X-axis；

V: automobile driving speed, unit km/h；

t_i: the time for reading mark is recognized from beginning read point B to end point E；

H: height of the ground to mark bottom, unit m；

B: the width of mark, unit m；

H: the view of driver is high, unit m；

For automobile from beginning read point B into end point E driving process, the view of driver is high to the rectangular pyramid spatial volume for indicating formation:

V_i=1/3abd ... (1-19)

In formula,

A: the length of mark, unit m；

B: the width of mark, unit m；

D: driver regards the high horizontal distance to mark, unit m；

Known by formula (1-8) and formula (1-16),

In formula,

D: driver regards the high horizontal distance to mark, unit m；

R: radius distance of the bend circular curve center of circle to mark, unit m；

R: the radius distance in the bend circular curve center of circle to automobile, unit m；

α: the angle that automobile is turned over relative to positive X-axis from beginning read point B to end point E when driving；

β: the straight line of mark to the bend circular curve center of circle and the angle of positive X-axis；

Formula (1-20) is substituted into formula (1-19), is obtained

In formula,

A: the length of mark, unit m；

B: the width of mark, unit m；

R: radius distance of the bend circular curve center of circle to mark, unit m；

R: the radius distance in the bend circular curve center of circle to automobile, unit m；

α: the angle that automobile is turned over relative to positive X-axis from beginning read point B to end point E when driving；

β: the straight line of mark to the bend circular curve center of circle and the angle of positive X-axis；

Formula (1-14) is substituted into formula (1-21), is obtained

In formula,

A: the length of mark, unit m；

B: the width of mark, unit m；

R: radius distance of the bend circular curve center of circle to mark, unit m；

R: the radius distance in the bend circular curve center of circle to automobile, unit m；

β: the straight line of mark to the bend circular curve center of circle and the angle of positive X-axis；

V: automobile driving speed, unit km/h；

t_i: the time for reading mark is recognized from beginning read point B to end point E.

3. the visual domain model of expressway bend mark according to claim 1 or 2, which is characterized in that the mark is Roadside sign board or hanging sign board.