Effectiveness of Your Speed Sign in Hua Hin Municipality 8/Issue 8/IJEIT1412201902_04.pdf · accident in order to warn and reminds the driver to keep their speed within the speed

ISSN: 2277-3754

ISO 9001:2008 Certified International Journal of Engineering and Innovative Technology (IJEIT)

Volume 8, Issue 8, February 2019

16

Effectiveness of Your Speed Sign in Hua Hin

Municipality Patchareeya Chaikaew

a, Chalermphol Chaikaew

b and Pornnarong Lueanpech

c,*

aDepartment of Civil Engineering, Rajamangala University of Technology Rattakosin,

Wang KlaiKangwon Campus, Prachuap Khiri Khan, Thailand

bDepartment of Civil Engineering, Rajamangala University of Technology Rattakosin,

Wang KlaiKangwon Campus, Prachuap Khiri Khan, Thailand

cDepartment of Civil Engineering, King Mongkut’s University of Technology North Bangkok, Bangkok, Thailand

Abstract: This study aims to investigate the effectiveness of

your speed sign on highway no.4 within the Hua Hin

Municipality, Prachuap Khiri Khan, Thailand. The vehicle

speed in several decision ranges was conducted by radar speed

gun and the spot speed distribution was utilized to explore the

vehicle speed behavior while approach and departed from your

speed sign. The 2 locations of the your speed sign on highway

no. 4 inbound direction was chosen as study area. The result

indicated that the speed behavior was different on each location,

vehicle tend to use high speed in the outward region more than

the central region. The your speed sign likely had consequence

for vehicles. Most of the vehicle tend to decrease their operating

speed while approach to the your speed sign and the effected

location was 250 meters prior to the your speed sign however,

the driver decided to accelerate again after departed the your

speed sign. The contrasting outcome has been occurred while

compared with the speed limit addressed by local government.

The finding shows that the 85th percentile speed of vehicle was

higher than speed limit both in outward region and central

region. In summary, this study concluded that even though the

your speed sign have got some benefit by slightly reduce the

vehicle speed however, it still not able to control the operating

speed lower than the speed limit. Therefore, the suggested

solutions to mitigate the speeding situation in study area

especially within the central region included the improvement of

physical geometry by adding the rumble strip with appropriated

distance and importantly combine with law enforcement

program. The contribution of this study will lead to assess the

efficiency of the speed sign and accident risk on the highway

no.4 within Hua Hin Municipality, Prachuap Khiri Khan

Province.

Keywords: spot speed, the85th percentile speed, speed limit,

accident.

I. BACKGROUND/ OBJECTIVES AND GOALS

The road accident is one of the major causes of death

globally, the highest rate was occurred in developing

country and from reveal of the www.worldatlas.com [1]

about the world's highest road deaths in the world within

the year 2017, stated that Thailand has been ranked as

number 1 in the world. The highest rate of traffic related

moralities at 36 per 100,000 people due to the increasing of

urbanization, inadequately traffic controlled, poor road

marking and signs and importantly the reckless and

intoxication while diving. Comprehensively, the impact of

road accidents did not affect only the victims but also

causes the huge losses of the Thai economy, society

especially lost in productivity of the country.

The Thailand Development Research Institute (TDRI) [2]

studied the loss of life and death from road traffic accidents

with the method of willingness to pay. This study found

that the value of death was about 10 million baht per person

while the value of serious injuries was about 3 million baht

per case. Based on that value for the loss assessment of the

whole country can be concluded that during the year

2011-2013, the average annual accident value was 545,435

million-baht, accounted for 6 percent of gross domestic

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product (GDP) of the country. However, even though the

road accidents had caused the huge losses in Thailand,

many of Thai people still lacking awareness of the hazards

and impacts of road accidents.

Considering the situation of road traffic accidents in

Thailand, it was found that Thailand road traffic accident

statistics compiled by the National Bureau of Statistics

stated that more than 60% of the cases were caused by

personal driving behavior [3]. The top three causes of

accidents in Thailand included unexpectedly lane change

25%, speeding over the speed limit 22% and driving too

close to another 19% respectively.

Focusing the traffic accident situation in Hua Hin

municipality, Prachuap Khiri Khan Province which is one

of the world's major tourist destinations in Thailand where

the location of KlaiKangwon Palace, local government

offices, Hua Hin beach and business district. The statistic

compiled by the National Bureau of Statistics stated that

the top three causes of accidents in Hua Hin municipality

included speeding over the speed limit 33%, less

experience driver 21%, and driving too close to another

14% [3] and regard to the number of accidents of Prachuap

Khiri Khan Province in the year 2017, the top three districts

with highest number of accidents included Hua Hin district

22%, Prachuap Khiri Khan city district 21% and Bang

Saphan district 18% respectively. Inspecting closely to the

proportion of deaths from road traffic accidents, we found

that within Hua Hindi strict had the highest proportion of

deaths from accidents [4].

Concerning the effected factor contribute to speed

decision, AASHTO [5] specified that the speed of the

vehicle was influenced by the physical characteristics of the

road, the weather, the type of vehicle and the speed limit

and importantly the factors related to the geometric design

of the road had been identified as the main factor to

determine the driving speed which consistent with the

speed limit addressing by the Land Traffic Act [6] of

Thailand. The vehicle speed behavior on different physical

characteristics of the road, Glennon et al. [7] investigated

the effect of curved roads to the vehicle operating speed.

The study indicated that there was not affected when the

radius of curve more than 800 meters, but the vehicle speed

tent to reduced significantly when the radius of curve was

less than 250 meters.

Jägerbr and Sjöbergh [8] studied the effect of vehicle

speed on the road from different lighting environment in

Sweden. This study concluded that the vehicle speed was

fluctuated by the time of day and the presence and absence

of the illumination system on road. The vehicle speed was

likely decreased in the unusual weather conditions liked

raining or snowing and the vehicle speed significantly

reduced in the unusual weather conditions on road that

without the illumination system.

In term of prevention strategies, the most popular

scheme to encountered with was the traffic calming. The

traffic calming was the physical improvement to prevented

and reduced the negative impact of a vehicle and changed

the driving behaviors. Jorgense and Mertne r[9]

investigated the outcome after applied the traffic calming

strategies in Denmark using before and after comparisons.

The results summarized that the speed control policy with

the traffic calming strategies had a positive tendency to the

traffic safety, perception of risk factors and improved the

environment quality within the area.

Recently in Thailand, the Department of Highways had

been installed the your speed sign in several locations in

Thailand especially the location where the highest rate of

accident in order to warn and reminds the driver to keep

their speed within the speed limit and to reduce the risk of

road accidents. The effectiveness of the your speed sign

was studied both in the UK and in the US, the result found

the effectively decrease the vehicle speed [10],[11] .Even

though the speed reductions less than resulting from

physical improvement but the your speed signs had the

major effect on drivers who exceeding the posted speed

limit and driving pass through the speed transition zones

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[12]. On highway no. 4 in Hue Hin Municipality, there

were 2 locations of the your speed sign had been installed

in order to maintain the vehicle speed in the inbound

direction heading to the Hua Hin central region.

The objective of this study was aimed to investigate the

effectiveness of your speed sign on highway no.4 within

the Hua Hin Municipality by conducting the vehicle speed

in several decision ranges with radar speed gun and

explored the vehicle speed behavior while approach and

departure from they our speed sign. The contribution of this

study will lead to assess the efficiency of the your speed

sign and accident risk on the highway no.4 within Hua Hin

Municipality, Prachuap Khiri Khan Province.

II. METHODS

A. Case Study and Data Collection

The study area was the highway no.4 within Hua Hin

Municipality, Prachuap Khiri Khan Province which the

main access road to the Klai Kangwon Palace, local

government offices, Hua Hin beach and business district.

The physical characteristic included the at-graded 6 lanes

road for 2 direction and divided by raise median. It also

included the exclusive lane for motorcycle in the most left

lane nearby shoulder lane. The physical characteristic and

location of the your speed sign illustrated in Fig 1.

(a) Your Speed sign at km

200+360

(b) Your Speed sign at km

213+850

Fig. 1. The physical characteristic and location of study area

The main objective of this study was to examine the spot

speed of vehicles using radar speed gun and to avoid the

effect from traffic condition, the vehicle speed data

collection was conducted during off-peak period (10.00

AM-03.00 PM). The post kilometer of highway no.4 km

200+360 and km 213+850 where the locations of the your

speed sign were selected as test bed. Apparently, each

location had unique characteristics, in example the location

of km 200+360 involved with the sight distance problem

because this station was located behind the sharp curve and

the location of km 213+850 related with speeding problem

because this area was the speed transition zones between

outward region and central region where differently speed

limit and most of the vehicle kept using their speed more

than speed limit. Beside of the your speed sign location, the

distance both in approach and depart of the your speed sign

at 500 m. and 250 m. were adopted as speed data collection

point to explore the vehicle speed behavior. The location

and distance of spot speed data collection point illustrated

in Fig 2.

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(a) Characteristics and data collection point of the km

200+360

(b) Characteristics and data collection point of the km

213+850

Fig. 1.The location and distance of spot speed data collection

point

B. Sample and Population

This study was captured the operating speed of vehicle

which classified according to their usage within the area.

The classification of vehicles as followed;

Passenger Car

Truck or Heavy Goods Vehicle

Bus

Motorcycle

The sample size in this study was determined based on the

vehicle speed behavior from 20 examples pilot test. The

appropriated number of sample was calculated following

this equation,

𝑛 = 𝑍𝛼∗𝜎

𝑒 2

(1)

Where 𝑛is the appropriate number of sample.

𝑍𝛼 is the Z score at the confidence level.

𝜎is the variance of the sample.

𝑒is the acceptable error.

The 20 examples pilot test found that the vehicle speed in

this area had a variance of 18.145 kph.While applied the

acceptable error less than 5 kph as well as the confident

level at 95 percent, it was concluded that the appropriated

sample size in the study area should contain at least 50

vehicles for each vehicle type. The data collection with

radar speed gun illustrated in Fig 3.

(a) data collection at the km

200+360

(b) data collection at the km

213+850

Fig. 2. The data collection with radar speed gun.

C. Data Analysis

The 85th percentile of vehicle speed was widely used for

traffic statistical analysis. It provided an accurate

estimation of traffic conditions determined the quality of

road design and evaluated the posted speed limits. The 85th

percentile of vehicle speed was considered differently by

road environment and it was defined as the speed at or

below which 85 percent of all vehicles were observed to

travel under free-flowing conditions past a monitored point.

The 85thpercentile value was calculated followed by the

assumption of normal distribution of traveling speeds and

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in term of traffic engineering, which typically used the 85th

percentile speed as a standard to set the speed limit at a safe

speed, minimizing crashes and promoting uniform traffic

flow along a corridor. Homburger et al. [13] also

hypothesized that the 85thpercentile of vehicle speed was

the speed that motorists consider to be traveling at safe

speeds and for the road design AASHTO [5] suggested that

the 85thpercentile of vehicle speed was considered to the

safest speed for the road segment. In this study, the vehicle

speed analysis was considered the 85thpercentile of vehicle

speed as a tool to determine the speed limits. The

85thpercentile of vehicle speed analysis concept illustrated

in Fig 4.

Fig. 3The 85th percentile of vehicle speed concept

Source: Modification from Lincoln Public Works and Utilities

III. RESULTS

A. Spot Speed Analysis

Table 1 shows the analysis results of the spot speed

collected at the several control points and the your speed

sign for the km 200+360 which located in the outward

region. The 85th percentile speeds were significantly

different in case of passenger car and motorcycle, the speed

behavior from both vehicles were similar with higher in

upstream and slightly decrease when close to the your

speed sign. At the your speed sign, the 85th percentile

speed of passenger car and motorcycle were reduced 5-15

kph from the upstream but after departed the your speed

sign, the speed of passenger car raised up to the free-flow

speed again. In case of truck and bus, the 85th percentile

speeds were not contrasting significantly. The speed of

truck and bus were steady in ranges 60-65 kph along the

upstream and downstream. The vehicle speed distribution

on the km 200+360 illustrated in Fig 5.

At your speed sign for the km 213+850 which located in

the central region. The 85th percentile speeds were

significantly different only in case of passenger car, the

speed behavior was higher in upstream and dramatically

decrease when close to your speed sign. At the your speed

sign, the 85th percentile speed of passenger car was

reduced 5-8 kph from the upstream but after departed the

Your Speed sign, The speed of passenger car raised up to

the free-flow speed again. In case of truck, bus and

motorcycle; the 85th percentile speeds were not contrasting

significantly. the speed of truck, bus and motorcycle were

steady in ranges 60-65 kph along the upstream and

downstream. The vehicle speed distribution on the km

213+850 illustrated in Fig 6.

Table 1. The 85th percentile speed of vehicle in the study area

Locati

on

Vehicle speed at

Outward Region

KM 200+360 (kph)

Vehicle speed at Central

Region

KM 213+850 (kph)

Car Tru

ck Bus MC Car

Tru

ck Bus MC

-500

m.

96.

70

65.3

0

61.9

5

82.

65

91.

25

64.3

0

62.

65

63.

30

-250

m.

82.

00

65.3

0

65.6

5

67.

00

82.

65

61.0

0

63.

65

63.

00

Your

Speed

Sign

86.

00

61.6

5

65.6

5

60.

00

77.

00

65.6

5

65.

00

61.

65

+250

m.

83.

00

60.6

5

62.9

5

64.

30

73.

00

66.6

5

67.

00

62.

60

+500

m.

91.

55

58.6

5

65.6

5

71.

00

88.

65

63.6

5

55.

65

61.

00

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(a) -500 m.

(b) -250 m.

(c) Your Speed Sign

(d) +250 m.

(e) +500 m.

Fig. 5. The vehicle speed distribution on the km 200+360

(a) -500 m.

(b) -250 m.

(c) Your Speed Sign

(d) +250 m.

(e) +500 m.

Fig. 6. The vehicle speed distribution on the km 213+85

B. Effect of Your Speed Sign

The speed sign was an interactive sign, generally

displayed the approach speed of vehicle. The main

objective of the your speed signs was to decrease the

vehicle speed by making drivers pay attention and aware

when they were driving at speeds above the posted speed

limits and it also used as a traffic calming device instead of

physical devices. In this study, the location of km 200+360

which involved with the sight distance problem, the result

shown that the your speed sign mostly effected to the

passenger car and motorcycle. The reduction in 85th

percentile speeds were ranging from 10 to 20 kph and the

effected location was 250 meters prior to your speed sign.

However, after departed your speed sign this study found

that the passenger car and motorcycle tend to accelerate their

speed again cause by lack of law enforcement. In case of the

truck and bus, the variance of 85th percentile speeds were still

uncertain. The effect of your speed sign on the km 200+360

illustrated in Fig 7.

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Fig. 7. Effect of the Your Speed sign on the km 200+360

The location of km 213+850 which related with speeding

problem due to the speed transition zones, the result shown

that the your speed sign mostly effected to the passenger

car. The reduction in 85th

percentile speeds were ranging

from 5 to 15 kph and the effected location was 250 meters

prior to your speed sign. Although, their transition to low

speed zone this study found that the passenger car tends to

accelerate their speed again after departed your speed sign

which increase the risk of accident especially in CBD area.

In case of the truck and bus, the variance of 85th

percentile

speeds were still uncertain. The effect of your speed sign on

the km 213+360 illustrated in Fig 8.

Fig.8. Effect of the Your Speed sign on the km 213+850

C. Comparing with the Speed Limit

The speed limit of road was usually set the maximum

speed of road which vehicles may legally drive. The speed

limit may be variable based on physical characteristic of

road and density of area. The speed limit was typically

addressed by the legislative agency of nations or local

governments and enforced by police officer. The overview

of this study found the reduction of operating speed while

approach to your speed sign and accelerated again after

departed. Considering to the speed limit addressed by local

government which stated that 80 kph within outward region

and 50 kph within central region. In this case, the

contrasting outcome has been occurred, the 85th percentile

vehicle speeds were higher than speed limit. Surprisingly,

within the central region all of the vehicles included

passenger car, truck, bus and motorcycle were kept using

higher speed. The comparison with the speed limit

illustrated in Fig 9 & Fig 10.

Fig. 9. Comparing with speed limit on the km 200+360

Fig. 10. Comparing with speed limit on the km 213+850

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IV. CONCLUSION

The main objective of this study was aimed to

investigate the effectiveness of your speed sign on highway

no.4 within the Hua Hin Municipality, Prachuap Khiri

Khan, Thailand. The result indicated that the speed

behavior was different on each location, vehicle tend to use

high speed in the outward region more than the central

region due to the traffic density and different of land use

and within the decision range, the your speed sign likely

had consequence for vehicles. Most of the vehicle tend to

decrease their operating speed and the reduction in 85th

percentile speeds were ranging from 5 to 20 kph while

approach to the your speed sign and the effected location

was 250 meters prior to the your speed sign however, the

driver decided to accelerate again after departed the your

speed sign. The contrasting outcome has been occurred

while compared with the speed limit addressed by local

government. The finding shows that the 85th percentile

speed of vehicle was higher than speed limit both in

outward region and central region.

In summary, this study concluded that even though the

your speed sign on highway no.4 within the Hua Hin

Municipality, Prachuap Khiri Khan, Thailand have got some

benefit by slightly reduce the vehicle speed however it still

not able to control the operating speed lower than the speed

limit. Therefore, the suggested solutions to mitigate the

speeding especially, within the central region included the

improvement of physical measure by adding the rumble strip

with appropriated distance and importantly combine with

law enforcement program. The contribution of this study will

lead to assess the efficiency of your speed sign and accident

risk on the highway no.4 within Hua Hin Municipality,

Prachuap Khiri Khan Province.

ACKNOWLEDGMENT

The funding in this research was partially supported by

Department Civil Engineering, Faculty of Engineering,

Rajamangala University of Technology Rattanakosin.The

author would like to thank for the students of Civil

Engineering Department, Rajamangala University of

Technology Rattanakosin, Wang KlaiKangwon Campus for

the data collection.

REFERENCES

[1] "worldatlas," 2018. [Online]. Available:

https://www.worldatlas.com/articles/the-countries-with-the-

most-car-accidents.html. [Accessed 26 April 2018].

[2] Thailand Development Research Institute (TDRI), "Road

Safety Assessment Project In the case of the Port of Tha

Luang And the Road to Friendship - Kaeng Khoi Cement

Plant," 2017.

[3] National Bureau of Statistics, "service.nso.go.th," 2015.

[Online]. Available:

http://service.nso.go.th/nso/web/statseries/statseries21.html.

[4] Thai Road Accident Data Center for Road Safety Culture,

"http://www.thairsc.com/," 2017. [Online]. Available:

http://rvpreport.rvpeservice.com/viewrsc.aspx?report=0486&

session=16..

[5] AASHTO, A policy on geomatric design of highways and

streets, 6th edition, Washington D.C., 2011.

[6] Royal Thai Police Department, "Land Traffic Act.," 1979.

[7] J. Glennon, T. Neuman and J. Leisch, "Safety and

Operational Considerations for Design of Rural Highway

Curves," Federal Highway Administration, 1985.

[8] A. Jägerbrand and J. Sjöbergh, "Effects of weather conditions,

light conditions and road lighting on vehicle speed," Springle

Plus, vol. 5, no. 505, 2016.

[9] L. Jorgense and J. Mertner, "Effects of traffic calming

schemes in Denmark," in 4th international Conference on

Urban Transport and the Environmt for 21th Century, Lisbon,

Portugal, 1998.

[10] E. Rose and G. L. Ullman, "Evaluation of dynamic speed

display signs," Texas Transportation Institute, Texas, 2003.

[11] D. Veneziano, L. Hayden and J. Ye, "Effective deployment of

radar speed signs," Western Transportation Institute,

Montana, 2010.

[12] W. Sandburg, T. Schoenecker, K. Sebastian and D. Soler,

"Long-term effectiveness of dynamic speed monitoring

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displays (DSMD) for speed management at speed limit

transitions," Washington County, Dakota County and

Ramsey County Department of Transportation., 2006.

[13] Homburger, W.S., J.W. Hall, R.C. Loutzenheiser and W.R.

Reilly, Spot Speed Studies, In Fundamentals of Traffic

Engineering, Berkeley:: Institute of Transportation Studies,

University of California, 1996.

Documents

Effectiveness of Your Speed Sign in Hua Hin Municipality 8/Issue 8/IJEIT1412201902_04.pdf · accident in order to warn and reminds the driver to keep their speed within the speed