Optimization Design of Traffic Marking in Urban CBD Area

Mujie Lu

, Wei Wang

, Yuxuan Wang

and Jingyao Qu

School of Transportation, Southeast University, Nanjing, Jiangsu, 210096, China

mujielu_seu@163.com,

wangwei_transtar@163.com,

220162592@seu.edu.cn and

220162623@seu.edu.cn

Keywords: Central Business District (CBD), Three-dimensional Marking, CAD 3D Modeling, Traffic Safety.

Abstract: With the increasing proportion of motorized traffic in urban transportation, the conflict between slow traffic

and motorized traffic has become more and more serious, which is especially prominent in urban CBD area.

This paper proposes the solution to the three-dimensional optimization of the deceleration marking and the

guidance marking, innovatively puts forward using CAD 3D modeling to design the shape and dimension of

traffic markings. By analyzing the human visual perception and visual illusion principle, the design method

and basis of the three-dimensional marking are gradually obtained. Three-dimensional marking was applied

in Nanjing, Jiangsu Province. The practice shows that three-dimensional marking has been significantly

improved in reducing vehicle speed and the degree of deviation, which can ensure the safety and order of

traffic in CBD area.

1 INTRODUCTION

Road traffic safety is a worldwide problem, and

researches on traffic accidents have been paid more

and more attention by the government recently. As

the core of one city, CBD area has high density of

humans and vehicles. Although the speed of vehicles

is not too fast in CBD area, for the deceleration zone

with intertwined traffic flow, a speed of 40 km/h is

high enough to threaten pedestrians. At the same

time, intertwined vehicles are also prone to traffic

accidents, and one accident may bring congestions

to the entire CBD area.

Due to land shortages in urban CBD area, some

necessary management facilities have to be replaced

by traffic marking. However, some of the marking

did not play a good role. Because the right of way

for pedestrians was ignored, the crosswalk line,

originally considered to be the "secure line", has

become a kind of "dead line". On roads without

supervision, vehicles pass through the guidance

marking arbitrarily, which is easy to cause traffic

disorder. In addition, the noise problem caused by

the uplift deceleration belt is more and more

concerned by the public, so researches on the

three-dimensional marking based on driver's

psychological effect began to rise.

Through the study of road visual illusion and

human visual illusion, this paper finds out the

scientific and rational design method of

three-dimensional marking. The research team also

carried out three-dimensional optimization design

for the existing traffic marking in CBD area in order

to improve the ban, warning and indication effect of

the marking, and to promote the harmonious

development of the road transportation in CBD area.

2 DESIGN PRINCIPLES

2.1 Design Ideas

The main idea of this research is that the traffic

marking is designed into a seemingly 3D shape

based on the analysis of human visual perception

and visual illusion. The three-dimensional marking

can attract driver's attention easily using the illusion

of obstacles, so as to optimize the deceleration or

guidance effect of the traffic marking. However, the

nature of traffic marking is the two-dimensional

graphics set on the road, therefore, in order to make

the traffic marking simulate the 3D effect better, the

research needs to start from the driver's perspective,

making the three-dimensional graphics plane in

order to obtain the shape and dimension of the traffic

marking.

246

Lu, M., Wang, W., Wang, Y. and Qu, J.

Optimization Design of Trafﬁc Marking in Urban CBD Area.

In 3rd International Conference on Electromechanical Control Technology and Transportation (ICECTT 2018), pages 246-251

ISBN: 978-989-758-312-4

2.2 Design Methods

2.2.1 Simulation of CAD Software

Open the 3D modeling window in AutoCAD

software and some feature parameters need to be

determined in the model firstly. As shown in Figure

1, the simulation of obstacles in front of the driver

requires three parameters, respectively:

A: The horizontal distance between the driver

and the front of road obstacle;

B: The dimensions of the road obstacle;

C: The vertical distance between the driver's line

of sight and the obstacle.

The horizontal distance between the driver and

the front of road obstacle shall not be less than the

safe braking distance of the vehicle, that is,





ASVt

(1)

Where S refers to the safety braking distance, ܸ

௜

refers to the initial velocity (the speed before

braking), t refers to the brake reaction time, ܸ

௙

refers to the final velocity (safety speed), and a

refers to the deceleration of the vehicle. The

dimensions of the road obstacle should be selected

in conjunction with the shape of the existing

marking and the width of the road. The vertical

distance between the driver's line of sight and the

obstacle can be taken in accordance with the

relevant national standards. After selecting these

parameters, shapes of the obstacle saw by the driver

can be got by using camera preview functions in the

CAD software.

Figure 1 Simulation of road scene using CAD software.

2.2.2 Design of Marking Colors

Previous researches show that visual perception

provides about 80% of traffic information to the

driver, thus, visual perception is the most important

way for drivers to obtain outside information.

Colorfulness is one of the advantages of the

three-dimensional marking because people's feeling

for color is rapid and lasting. For three-dimensional

marking, the combination of colors should be

considered to make the overall effect better. Based

on the hue circle and the national standard of road

traffic sign and marking (GB-5768), and taking into

account the color matching effect of pavement and

marking, this research ultimately determines that the

color combinations of the three dimensional marking

are white, blue and yellow, and the specific color

scheme is determined by the shape of the marking.

3 RESEARCH CONTENTS

3.1 Investigation of CBD Traffic

Taking Xinjiekou, the CBD area of Nanjing, as an

example, the research team investigated the current

traffic organization in the CBD area and analyzed

the traffic organization problems according to the

survey data.

One investigation was conducted at an

unsignalized intersection in Zhongshan Road,

Xinjiekou area. The research team captured video to

record the situation of pedestrian crossing the street,

and used the handheld radar tachometer to record the

speed of vehicle through the crosswalk line.

According to statistical analysis, in the surveyed 165

motor vehicles, 72.1% of the vehicles have safety

speed which is below 30 km/h, but there are still

27.9% of the vehicles can reach the speed near 40

km/h or even higher.

Another investigation was conducted at the

intersection of Zhongshan Road and Dashiqiao

Street in Xinjiekou area, and there are guidance

markings for traffic channelization on the main road.

During the survey, it was found that when going

straight on the main road and turning right on the

secondary road were allowed at the same time,

vehicles will pass through the guidance marking

arbitrarily, there will be obvious traffic conflicts in

the diversion island so that influence the smooth

operation of the entire intersection.

In view of the above problems, this paper

proposes to realize the optimization of traffic

organization by using three-dimensional marking.

After the transformation, the three-dimensional

marking can achieve two optimization effects:

deceleration and guidance.

3.2 Design of Deceleration Marking

3.2.1 The Horizontal Distance between the

Driver and the Traffic Marking

Firstly, determine the brake reaction time. It includes

the response time of both the driver and the vehicle.

Optimization Design of Trafﬁc Marking in Urban CBD Area

247

According to the results of previous studies, the

brake reaction time is about 0.5-0.6 seconds under

normal circumstances. Thus, in this paper, the value

of brake response time t is 0.5 s.

Secondly, determine the brake deceleration. For

ordinary passengers in the vehicle, when the brake

deceleration is less than 1.8 m/s

, people's feeling is

not so significant; when the deceleration reaches 3.6

m/s

, the feeling of people is obvious. Thus, in this

paper, the value of brake deceleration a is 1.8 m/s

Finally, determine the initial and final velocity of

the vehicle. It is considered to be high speed when

vehicles can reach the speed of 40 km/h in CBD area,

and relevant statistics show that when the collision

speed is 30 km/h, the pedestrian mortality rate is less

than 5%, but when the collision speed is 40 km/h,

the rate is up to 45%. Thus, in this paper, the value

of the initial velocity ܸ

௜

is 40 km/h, and the value

of the final velocity ܸ

௙

is 30 km/h.

Substitute the above parameters into the formula

1, the safety braking distance S equals to 20.56 m.

Considering that there is still some distance between

the driver's position and the front of the vehicle, the

value of the horizontal distance between the driver

and the traffic marking A is 22 m.

3.2.2 The Physical Shape and Dimensions of

the Obstacle

Firstly, select shape of the obstacle. Relevant data

indicate that the visual impact of the prism to human

eyes is relatively moderate. The three-dimensional

entity of triangular prism can properly create a

reasonable sense of slope on the road, so that the

three-dimensional effect of the marking simulation is

more real. Thus the three-dimensional entity used in

the simulation is triangular prism.

Secondly, when determining the cross-sectional

dimensions of the obstacle, the compatibility with

road width needs to be considered. Generally, the

width of a single lane is 3.5 m, and the average

width of vehicles is 2.5 m. In order to ensure that the

distance between the designed markings is not less

than the vehicle width, the distance between the

edge of designed marking and the road edge should

be 0.5 m. At the same time, considering that setting

up two three-dimensional markings on the same

cross-section of each lane can uniformly fill the

entire width of the pavement. Thus the width of the

three-dimensional marking is 1.0 m.

Finally, determine the projective length of the

obstacle. In the national standard GB-5768, the

spacing distance between most of the deceleration

markings is in the range of 5 to 20 meters. Taking

into account the cross-sectional dimension, choose 5

m as the projective length of the three-dimensional

marking, that is, the value of the road obstacle

dimension B is 5 m.

3.2.3 The Vertical Distance between the

Driver's Line of Sight and the Obstacle

According to the national standards, the height of

driver's eye in vehicle is 1.2 m, that is, the value of

vertical distance between the driver's line of sight

and the obstacle C is 1.2 m.

3.2.4 Simulation Results

The parameters A (22 m), B (5 m) and C (1.2 m) are

input to the simulation scene (Figure 1). The

projective pattern observed from the camera's

perspective is captured, and the geometric

dimensions are plotted in the software to complete

the dimension design. Combined with the study of

colors, the final design of the deceleration marking

is shown in Figure 2.

Figure 2 Deceleration marking design results.

3.3 Design of Guidance Marking

The prototype of the three-dimensional guidance

marking is derived from the diamond longitudinal

deceleration marking, and the design method is

similar to that of the deceleration marking in section

3.2. In order to enhance the guidance function of the

marking, sweep the diamond plane alone the oblique

direction in AutoCAD software, and select the

sweeping result oblique hexahedron as the

three-dimensional entity. The specific design of the

guidance marking is as follows (details similar with

the deceleration marking are not repeated here):

3.3.1 The Dimensions of the Obstacle

According to the relevant regulations in the national

standard GB5768, the length of road longitudinal

deceleration marking should be 100 cm, which is the

same with the length of three-dimensional guidance

marking. In order to avoid too much pressure for the

ICECTT 2018 - 3rd International Conference on Electromechanical Control Technology and Transportation

248

driver in the process of driving, the width of

three-dimensional marking is set to 32.5 cm. The

road width is more than 3.1 m after subtracting the

marking width, which still belongs to the driver's

acceptable range.

3.3.2 Simulation Results

Considering the requirement of convenient

construction, the perspective projection is simply

optimized to remove the small angle change caused

by the sight distance. The optimized result is the

final design result of the three-dimensional guidance

marking which is shown in Figure 3.

Figure 3 Guidance marking design results.

4 EXPERIMENT VERIFICATION

The research team set up two kinds of

three-dimensional markings in Southeast University

Jiulonghu campus and carried out two sets of

experiments to test the deceleration and guidance

effect of the three-dimensional markings in practical

application. The speed change rate on the straight

and the deviation of the trajectory on the curve were

selected as the evaluation index in the experiments.

4.1 Deceleration Marking Verification

The experimental verification of the deceleration

marking is located on the straight and consists of

two groups of experiments, which belongs to the

comparison experiment. The difference between the

two groups is only in the way laying the same

deceleration marking on the road, forward and

reverse. The effect of layouts is shown in Figure 4.

Figure 4 Forward and reverse layouts.

In order to make the experimental results more

universal, a total of 10 drivers participated in the

experiment. When the test driver drove through the

experimental section, the other two team members

respectively measured the speed of the vehicle into

and out of the experimental section with hand-held

radar tachometer. A total of 20 sets of data were

measured to calculate the speed change rate, the

changes of vehicle speed are shown in Table 1.

Table 1 Speed change of vehicles passing through

experimental sections.

Forward Layouts Reverse Layouts

௜

(km/

௙

(km/

Speed

Chang

e Rate

(

)

௜

(km/

௙

(km/

Speed

Chang

e Rate

(

)

1 21 14 33.3% 20 15 25.0%

2 30 19 36.7% 35 27 22.9%

3 35 26 25.7% 39 30 23.1%

4 37 25 32.4% 40 33 17.5%

5 38 28 26.3% 40 34 15.0%

6 42 33 21.4% 42 36 14.3%

7 45 36 20.0% 44 36 18.2%

8 50 30 40.0% 50 42 16.0%

9 58 40 31.0% 53 40 24.5%

10 61 46 24.6% 58 46 20.7%

Ave 41.7 29.7 29.2% 42.1 33.9 19.7%

It can be seen from the above table that the actual

deceleration effect of the forward layouts (29.15%)

is significantly better than that of the reverse layouts

(19.71%). After vehicles passing through the

deceleration marking in forward layouts, the average

speed can be controlled below the safe speed at 30

km/h. Therefore we can draw a conclusion that the

three-dimensional deceleration marking can achieve

good deceleration effect in the practical application.

4.2 Guidance Marking Verification

The experimental verification of the guidance

marking is located on the curve and consists of two

groups of experiments, which belongs to the control

experiment. There were no any treatments to the

curve in the control group, but guidance marking

was laid on the curve in the experimental group. The

effect of layouts in experimental group is shown in

Figure 5.

Optimization Design of Trafﬁc Marking in Urban CBD Area

249

Figure 5 Guidance marking layouts.

Before the start of the experiment, take off the

model aircraft near the experimental areas, and set

the model aircraft hovering automatically above the

experimental section to begin the observation

mission. When participants drove through the

experimental section, it was recorded by the camera.

Latter using video processing software to extract the

vehicle trajectory through the curve with or without

the guidance marking respectively, and to compare

the deviation of the trajectory when vehicles passing

through the curve.

After the technical processing, the trajectory of

vehicles passing through the curve is shown in

Figure 6.

Figure 6 Comparison graphs of vehicles' trajectory.

It can be seen from the figure that the trajectory

of the vehicle passing through the curve in the case

without the guidance marking is closer to the edge of

the road than the trajectory in the case with the

guidance marking, and the guidance marking plays a

role in reducing the lateral deviation of the vehicle

on the curve. By contrast we can draw a conclusion

that the three-dimensional guidance marking can

achieve good guidance effect in the practical

application.

5 CONCLUSION

In this paper, through the analysis of human visual

perception and visual illusion principle, designing

method and basis of three-dimensional marking are

gradually got. This paper aims to make up for the

lack of research on three-dimensional marking, so as

to form the research system for three-dimensional

marking. Finally the design of the three-dimensional

marking applicable to different road conditions can

be used directly for the traffic departments. The

research results are summarized as follows:

First, this paper presents a scientific method to

design three-dimensional marking, which can

achieve good visual illusion of obstacles, and gives a

detailed design scheme of three-dimensional

deceleration and guidance markings;

Second, the three-dimensional guidance marking

designed in this paper can be used to reduce the

lateral deviation of the vehicle, and the deceleration

marking can be optimized by analogy to make it

have a three-dimensional effect;

Last, this paper makes three-dimensional

optimization design to some traffic markings in

urban CBD area, which can solve some problems

existing in reality and improve safety and order for

traffic in CBD area.

Reasonable traffic organization is particularly

important for the urban CBD area with shortages of

land and high traffic flow. The three-dimensional

marking proposed by this paper can adapt well to the

traffic characteristics of the CBD area, and solve

some traffic problems. What's more, the

three-dimensional marking with low cost and

obvious effect, is suitable for promotion in urban

CBD area to ensure the safety and order of the CBD

area. For urban CBD area, the three-dimensional

marking will have very broad prospects for

development!

ACKNOWLEDGEMENTS

This research was supported by the key project of

National Natural Science Foundation of China

(Grant No.51338003).

REFERENCES

Charlton, S. G., Mackie, H. W., et al, 2010. Using

endemic road features to create self-explaining roads

and reduce vehicle speeds. Accident Analysis &

Prevention, 2010, 42(6):1989-1998.

Katz, B. J. & Duke, D. E, 2006. Design and Evaluation of

Peripheral Transverse Bars to Reduce Vehicle Speeds.

Transportation Research Board 85th Annual Meeting.

Liang, G., Qian, G., Wang, Y, et al, 2017. Design of a

3-dimensional visual illusion speed reduction marking

scheme. International Journal of Occupational Safety

& Ergonomics, 2017, 23(1): 92-104.

Puan, O. C., Halim, S., & Ibrahim, M. N, 2015. Empirical

evaluation of drivers’ operating speeds along

ICECTT 2018 - 3rd International Conference on Electromechanical Control Technology and Transportation

250

curvatures on single carriageway roads. Jurnal

Teknologi, 2015, 73(4).

Qin, B., Liu, W., Shen, X., et al, 2013. A general

framework for road marking detection and analysis.

International IEEE Conference on Intelligent

Transportation Systems, IEEE, 2013:619-625.

Optimization Design of Trafﬁc Marking in Urban CBD Area

251