This study intended to address the problem of damaged (collapsed, cracked and decreased soil strength) road pavement structure built on clay soil due to clay soil properties such as low shear strength, high soil compressibility, low soil permeability, low soil strength, and high soil plasticity. Previous research reported that ground granulated blast slag (GGBS) and fly ash can be used for clay soil stabilizations, but the results of past research indicate that the road pavement construction standards remained unfulfilled, especially in terms of clay’s subgrade soil. Due to this reason, this study is carried out to further investigate soil stabilization using GGBS and fly ash-based geopolymer processes. This study investigates the effects of GGBS and ratios of fly ash (solid) to alkaline activator (liquid) of 1:1, 1.5:1, 2:1, 2.5:1, and 3:1, cured for 1 and 7 days. The molarity of sodium hydroxide (NaOH) and the ratio of sodium silicate (Na2SiO3) to sodium hydroxide (NaOH) was fixed at 10 molar and 2.0 weight ratio. The mechanical properties of the soil stabilization based geopolymer process were tested using an unconfined compression test, while the characterization of soil stabilization was investigated using the plastic limit test, liquid limit test, scanning electron microscopy (SEM), X-ray diffraction (XRD), and Fourier transform infrared spectroscopy (FTIR). The results showed that the highest strength obtained was 3.15 MPA with a GGBS to alkaline activator ratio of 1.5 and Na2SiO3 to NaOH ratio of 2.0 at 7 days curing time. These findings are useful in enhancing knowledge in the field of soil stabilization-based geopolymer, especially for applications in pavement construction. In addition, it can be used as a reference for academicians, civil engineers, and geotechnical engineers.

Malaysia is listed as one of Asia's developing countries with high-road accidents rate. The accident involves the most between the motorcyclist and other vehicles such as a passenger car which is 17 times safer than the motorcyclist. Current research reveals that the three major forms of incidents in Malaysia are single-motorcycle incidents, passenger car crashes and carsmotorcycles crash. In general, the lack of accuracy of road geometric design, traffic volumes and overlapping movements of vehicles was the main cause of road accidents in Malaysia, which caused drivers to make mistakes and errors due to road geometric characteristics and traffic environments. However, during our recent COVID-19 pandemic, the traffic volumes are relatively low in the whole country as the government announces the movement control order in March 2020. The country was almost completely lockdown (people and vehicles' movements were controlled). In contrast with the reduction of the traffic volumes, the number of crashes shows relatively high numbers. This phenomenon can be derived so that other factors cause vehicle crashes and fatalities should be considered. Several factors related to road geometric such as lane width, shoulder width, access point, curve length and tangent length are considered in developing profiles of operating speed for motorcycles and cars formed of tangents and curves. The analysis of the geometric factors and traffic environments took place at federal road F0050 from 21 to 25 km in Johor, Malaysia. This study was carried out using GPS (DG-200) where the data (vehicles tracked movements) on the continuous speed profiles used a current method of analysis to determine the profiles of road design consistency for motorcycles and cars. The profiles are used to measure the importance index of the integrated design consistency model of the road. The model depends on parameters such as the confine region of speed profiles, average speed, and velocity deviation standard of the profiles. Therefore, a special software of ACAD was used to build the profile of the consistency model. The design accuracy of the speed profile in traffic and safety assessments are affected by the integrated-consistency model. The highest number of accidents has been identified at 24 km at F0050 based on the area design consistency where poor design is the integrated quality consistency model for car and motorcycle. The study shows that crashes and fatalities are not fully affected by traffic volumes but road design performances and driving behaviors.

The city of South Jakarta is a dense metropolitan city because it has a high population growth rate. Due to this population growth, the city of South Jakarta has experienced additions, expansion of social facilities and infrastructure as well as transportation to serve the needs of its residents, one of which is the Lenteng Agung-West Tanjung Flyover Development Project. The infrastructure built has an impact on traffic congestion on the performance of the Lenteng Agung-Tanjung Barat road and Pasar Minggu intersection. The purpose of this study is to determine road performance and to know strategies that can be used to overcome the impact of traffic congestion. The method used in this analysis and discussion is based on the Indonesian Road Capacity Manual (MKJI), 1997 and conducts a field survey for the performance of roads and intersections without signals. The results of the research obtained on the performance of the Unmarked Intersection road are the largest traffic volume of the Unmarked Intersection which is obtained from the survey results on Friday 18 December 2020 and the peak hours are at 06.30-07.30 WIB With the degree of saturation DS = 0.66, the delay at the intersection is 10.85 sec / pcu and the chances of queuing are 36.97% -17.96%. In the analysis of the Lenteng Agung road section, the highest level of service was obtained on Monday, November 16 2020 in the morning at 07: 30-08.30, with a degree of saturation of 0.98 having a service level of E, which means the flow is unstable. Meanwhile, in the afternoon, 16: 00-18: 30 with a saturation degree of 0.53 and has a service level of B.

The unsignalized intersection which is located in Cileungsi District, precisely on Jalan Cileungsi Setu and Jalan Raya Narogong, is a commercial area with dense economic activity and densely populated settlements. As a result of the dense activity, congestion occurs due to the large number of vehicles passing the road, especially during peak hours, namely the morning and evening. Seeing this problem, an analysis is needed that aims to determine the volume, performance of roads, and unmarked intersections as measured by capacity, degree of saturation, and level of service.  In analyzing this study using the Indonesian Road Capacity Manual (MKJI) 1997 method which will determine the performance of roads and intersections without signs. The data needed in this research are primary data in the form of geometric road data, traffic volume, vehicle speed data, and side friction. As well as secondary data in the form of location maps, land use, and population data. From the results of data analysis and processing, the busiest traffic flow at the intersection occurred on Sunday, November 15, 2020 at 17.30 - 18.30 WIB, the saturation degree value was 1.17 with LOS F. By doing an alternative solution, the saturation degree value was 0.68 and LOS B with placing signs are prohibited from stopping around intersections, and prohibiting the flow of traffic turning right either from the main road D to the Minor C road or from the Minor C road to the main road B. On Jalan Raya Narogong, the degree of saturation is 0.74 LOS C service, this shows that the road sections do not exceed the figure required by MKJI 1997, namely ≤ 0.75.

Accidents are unintentional or unexpected events that result in death, injury or property damage. Broadly speaking, accidents are caused by four factors, namely humans, vehicles, roads and the environment. This is related to the higher the number of vehicles, the more accidents occur. One of the factors suspected of causing an increase in the number of vehicles is the lack of public awareness of the role of public transportation advice.Traffic Conlict Technique (TCT) is an observation method that is carried out by recording near-accident events and seeing patterns of accidents. Traffic Conflict Engineering (TCT) was developed by the Department of Traffic Planning and Engineering at Lund University in Sweden. Time to Accident (TA) is the time remaining since the evasive action is taken until the time of the collision if the road user changes the vehicle speed and does not change the direction of the vehicle speed. This study uses data from the conflict survey and vehicle speed survey data that have been carried out. This study was conducted by identifying and analyzing the behavior of motorcyclists that affect the occurrence of accidents.The research location is on the Cileungsi Highway which is divided into 2 segments. Segment 1 starts from Hermina Hospital to Grand Mekarsari. Next, segment 2 starts from Grand Mekarsari to Citraland. The results showed that the research location has the potential to cause a front-front collision accident (in segment 1) front-side (in segment 2) at 09: 00 – 10: 00. 15:00 is a front-front collision (in segment 1) and a front-side collision (in segment 2). The results of the study are expected to provide an overview in estimating accidents so that preventive actions can be taken to improve traffic safety.