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Fulltext Modelling slope topography of a hilly terrain using unmanned aerial vehicle image technique

Neza Ismail, Fatin Zur Natasha, Wan Mohamed Syafuan, Ng, Choy Peng

ZULFAQAR International Journal of Defence Science, Engineering & Technology, 2021;4(1):17-24.
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Unmanned Aerial Vehicle (UAV) as data acquisition tools are becoming more affordable for many civil engineering applications. However, the accuracy of the output is influenced by many parameters. The main objective of this study was to investigate the effect of flight altitude toward the final output measurement accuracy without using Ground Control Point (GCP). Altitude is a parameter that is very important in flying UAV that has to be taken into consideration. Notably, the flight altitude depends on the ground condition, surrounding obstruction, Ground Sample Distance (GSD) and camera monitoring. The UAV should fly in a lower condition when GSD is better. However, this approach rarely can succeed because different site conditions such as flat terrain nor hilly terrain required different flight planning. Therefore, a field experiment will be carried out to investigate the optimum flight altitude to obtain acceptable accuracy of orthomap at hilly type of terrain. This study evaluates both the qualitative of the image and the quantitative aspect of the orthomap. The actual measurement of selected features was made and compared with the on screen measurement. An orthophoto will be generated by using Pix4Dmapper on a selected slope of the hilly terrain in UPNM Campus. Based on the results, different accuracy obtain on flat surface is 0.14% and slope surface is 2.77%, which needed further study to identify the method to reduce error. It is found that the accuracy without GCP is not having large error of more than 1% for flat area. Due to distortion of image on slope surface, the error is larger and needed GCP calibration. This study shows that UAV is a feasible platform for mapping of small area with acceptable accuracy.
Fulltext Development of a composite pavement performance index to monitor the pavement condition in UPNM

Muhammad Nur Arsyad Azman, Ng, Choy Peng, Faridah Hanim Khairuddin, Neza Ismail, Wan Mohamed Syafuan Wan Sabri

ZULFAQAR International Journal of Defence Science, Engineering & Technology, 2020;3(1):23-31.
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Road surface condition of a pavement is one of the most important features as it affect driving comfort and safety. A good road surface condition could reduce the risk of traffic accidents and injuries. Pavement Condition Index (PCI) is one of the important tools to measure the pavement performance. By conducting pavement evaluation, civil engineers could prioritize the maintenance and rehabilitation which usually incurred a huge cost. In University Pertahanan Nasional Malaysia (UPNM), there was no proper maintenance and rehabilitation scheduled for the roads as no performance evaluation tool available to measure the pavement condition. Thus, the objective of this study was to develop a Composite Pavement Performance Index (CPPI) to monitor the pavement condition and to rank the roads in UPNM. To develop the CPPI, road defects data were collected from 6 internal roads in UPNM. From the data collected, 4 major distresses were identified: longitudinal cracking, crocodile cracking, potholes and ravelling were found more likely to affect the pavement’s condition in UPNM. By measuring the growth of the distresses over a period of 6 months, modelling was conducted using simple linear regression. The growth of the distresses were compared, and odds ratios were computed to calculate the weightage of each distress for the determination of the CPPI value. The CPPI value developed could be used to rank the roads in UPNM. This study demonstrated that the road connecting to the library building in UPNM experienced the worst pavement deterioration with a PCI of 24 or a CPPI value of 1.1915. The level of severity was classified as “SERIOUS” in accordance to ASTM D6433. This road was recommended for reconstruction to increase the comfort and safety for road users
Factors related to seatbelt-wearing among rear-seat passengers in Malaysia

Ng CP, Law TH, Wong SV, Kulanthayan S

Accid Anal Prev, 2013 Jan;50:351-60.
PMID: 22633252 DOI: 10.1016/j.aap.2012.05.004

The benefit of wearing a rear seatbelt in reducing the risk of motor vehicle crash-related fatalities and injuries has been well documented in previous studies. Wearing a seatbelt not only reduces the risk of injury to rear-seat passengers, but also reduces the risk of injury to front-seat occupant who could be crushed by unbelted rear-seat passengers in a motor vehicle crash. Despite the benefits of wearing a rear seatbelt, its rate of use in Malaysia is generally low. The objective of this study was to identify factors that are associated with the wearing of a seatbelt among rear-seat passengers in Malaysia. Multinomial logistic regression analysis of the results of a questionnaire survey of 1651 rear-seat passengers revealed that rear-seat passengers who were younger, male, single and less educated and who had a perception of a low level of legislation enforcement, a lower risk-aversion and less driving experience (only for passengers who are also drivers) were less likely to wear a rear seatbelt. There was also a significant positive correlation between driver seatbelt and rear seatbelt-wearing behaviour. This implies that, in regards to seatbelt-wearing behaviour, drivers are more likely to adopt the same seatbelt-wearing behaviour when travelling as rear-seat passengers as they do when driving. These findings are crucial to the development of new interventions to increase the compliance rate of wearing a rear seatbelt.
The motorcycle deaths to passenger car deaths ratio and economic performance: A panel data analysis

Sirajudeen AO, Law TH, Wong SV, Ng CP

Accid Anal Prev, 2022 Feb;165:106533.
PMID: 34902624 DOI: 10.1016/j.aap.2021.106533

The existing literature in road safety revealed that the relationship between motorcycle deaths and per-head income follows a Kuznets or reverse U-curve pattern, whereby motorcycle deaths incline at lower income levels but decline once the per-head income has exceeded a threshold level. The same reverse U-curve relationship was also observed between per-head income and other road injury-related variables, including road deaths, road injuries, as well as road deaths to road injuries ratio. Evidence showed that motorcycles and passenger cars are the dominant vehicle modes and contributed significantly to global road deaths. The main objective of this study is to examine the relationship between the motorcycle deaths to passenger car deaths (MDC) ratio and per-head Gross Domestic Product (GDP). Examining the relationship between the MDC ratio and GDP per capita can be effective in understanding the relative change between motorcycle and passenger car deaths at different economic development stages, as well as identifying appropriate preventive measures. We apply a panel linear regression analysis on a panel of 38 countries over the period 1965-2013. Result demonstrated that there is a reverse U-curve relationship between the MDC ratio and the logarithm of GDP per capita. This implies that, at lower levels of GDP per capita, motorcycle deaths were more prevalent than passenger car deaths, whereas as the level of GDP per capita rises, passenger car deaths became relatively prevalent than motorcycle deaths. Moreover, there is a reverse U-shaped relationship between motorcycle ownership to passenger car ownership ratio (MPC) and the MDC ratio, while a U-shaped relationship exists between relative growth in higher mobility roads as compared to higher accessibility roads (MPA) and the MDC ratio. Based on our results, policies and interventions to reduce motorcycle and passenger car deaths were suggested in the conclusion of the paper.
Fulltext The sources of the Kuznets relationship between the COVID-19 mortality rate and economic performance

Law TH, Ng CP, Poi AWH

Int J Disaster Risk Reduct, 2022 Oct 15;81:103233.
PMID: 36093278 DOI: 10.1016/j.ijdrr.2022.103233

This paper discusses the findings of an empirical analysis of the Kuznets, or reverse U-shaped relationship, between the COVID-19 mortality rate and economic performance. In the early stages of economic development, the COVID-19 mortality rate is anticipated to rise with rising economic activity and urbanization. Eventually, the mortality rate decreases at higher economic development levels as people and the government are more capable of investing in disease abatement measures. The quality of political institutions, wealth distribution, urbanization, vaccination rate, and improvements in healthcare systems are hypothesized to affect the COVID-19 mortality rate. Examining this relationship can be effective in understanding the change in the COVID-19 mortality rate at different economic performance stages and in identifying appropriate preventive measures. This study employed the negative binomial regression to model a cross-sectional dataset of 137 countries. Results indicated that the relationship between the per-head gross domestic product (GDP) level and the COVID-19 mortality rate appeared to follow a pattern like the Kuznets curve, implying that changes in institutional quality, healthcare advancements, wealth distribution, urbanization, vaccination rate, and the percentage of the elderly population were significant in explaining the relationship. Improvement of the healthcare system has a notable effect on lowering the COVID-19 mortality rate under more effective government conditions. Additionally, the results suggested that a higher per-head GDP is required to reverse the rising trend of the mortality rate under higher income inequality. Based on these results, preventive measures, and policies to reduce COVID-19 mortalities were recommended in the conclusion section.
Role of sensory and cognitive conspicuity in the prevention of collisions between motorcycles and trucks at T-intersections

Law TH, Ghanbari M, Hamid H, Abdul-Halin A, Ng CP

Accid Anal Prev, 2016 Nov;96:64-70.
PMID: 27505097 DOI: 10.1016/j.aap.2016.04.013

Motorcyclists are particularly vulnerable to injury in crashes with heavy vehicles due to substantial differences in vehicle mass, the degree of protection and speed. There is a considerable difference in height between motorcycles and trucks; motorcycles are viewed by truck drivers from downward angles, and shorter distances between them mean steeper downward angles. Hence, we anticipated that the effects of motorcycle conspicuity treatments would be different for truck drivers. Therefore, this study aims to evaluate the effects of motorcycle conspicuity treatments on the identification and detection of motorcycles by truck drivers. Two complementary experiments were performed; the first experiment assessed the impact of motorcycle sensory conspicuity on the ability of un-alerted truck drivers to detect motorcycles, and the second experiment assessed the motorcycle cognitive conspicuity to alerted truck drivers. The sensory conspicuity was measured in terms of motorcycle detection rates by un-alerted truck drivers when they were not anticipating a motorcycle within a realistic driving scene, while the cognitive conspicuity was determined by the time taken by alerted truck drivers to actively search for a motorcycle. In the first experiment, the participants were presented with 10 pictures and were instructed to report the kinds of vehicles that were presented in the pictures. Each picture was shown to the participants for 600ms. In the second experiment, the participants were presented with the same set of pictures and were instructed to respond by clicking the right button on a mouse as soon as they detected a motorcycle in the picture. The results indicate that the motorcycle detection rate increases, and the response time to search for a motorcycle decreases, as the distance between the targeted motorcycle and the viewer decreases. This is true regardless of the type of conspicuity treatment used. The use of daytime running headlights (DRH) was found to increase the detection rate and the identification of a motorcycle by a truck driver at a farther distance, but effect deteriorates as the distance decreases. The results show that the detection rate and the identification of a motorcyclist wearing a black helmet with a reflective sticker increases as the distance between the motorcycle and the truck decreases. We also found that a motorcyclist wearing a white helmet and a white outfit is more identifiable and detectable at both shorter and longer distances. In conclusion, although this study provides evidence that the use of appropriate conspicuity treatments enhances motorcycle conspicuity to truck drivers, we suggest that more attention should be paid to the effect of background environment on motorcycle conspicuity.
The sources of the Kuznets relationship between the road deaths to road injuries ratio and economic growth

Sirajudeen AO, Law TH, Wong SV, Jakarni FM, Ng CP

J Safety Res, 2021 09;78:262-269.
PMID: 34399922 DOI: 10.1016/j.jsr.2021.06.007

INTRODUCTION: Past empirical studies indicated that there is a Kuznets or reverse U-shaped relationship between road deaths and per capita income, such that the number of road death increases at a low level of per capita reverse U-shaped relationship was observed between road injuries and per capita income. While these studies explored the impact of per capita income on road deaths and road injuries, no studies have examined the relationship between per capita income and road death to road injury ratio (DPI).
METHOD: Using a fixed effects panel regression analysis from 67 countries spanning over a period of five decades (1960-2013), the present study sought to explore the impact of per capita gross domestic product (per capita GDP) on the DPI ratio and the underlying factors responsible for the relationship.
RESULTS: Our result suggests that per capita GDP followed a reverse U-shaped relationship with DPI. Moreover, the relative improvements in higher mobility roads as compared to improvements in higher accessibility roads, motorcycle ownership to passenger car ownership ratio, percentage of population living in an urban area, infant mortality rate, and the percentage of population below 15 years of age and above 64 years of age contributed to this relationship. Practical Applications: This implies that, at lower level of economic growth where road deaths exceed road injuries, countries should implement low-cost measures to combat road deaths cases. Such measures include mandating wearing of quality helmets and daytime running headlights for motorcycles. On the other hand, at higher level of economic growth where road injuries surpass road deaths, countries are encouraged to devote more resources to improving medical technology and services to treat road injury victims, mandating seatbelt use, as well as enhancing and promoting public transportation service.