Performance Analysis of Unsignalized Intersection Using PTV VISSIM Software Modeling (Case Study of Sakra 4-way intersection, East Lombok)

Sakra 4-way intersection is one of the unsignalled intersections in East Lombok. At certain times of the day, there are frequent traffic jams and queues of moving vehicles at this intersection because the area surrounding the intersection is a commercial area, as evidenced by the presence of settlements, markets, mosques, village heads’ offices, shops, and other shopping centers. This research aims to determine the movement of traffic flow at the 4-way Sakra intersections in East Lombok using Vissim software modeling. Data collection was obtained from literature studies and direct surveys at the research site. Direct questionnaires at the research location and literature reviews were used to collect data. Using PTV VISSIM software modeling, the intersection of Sakra East Lombok was modeled under the current conditions on Monday and Sunday. The results showed that values for Monday were Queue Length (Qlen) 34.77 m and Tundaan (VehDelay) 19.95 sec / skr. The value of Tundaan (VehDelay) on Sundays is 16.68 sec/skr, the value of Queue Length (Qlen) on Sundays is 23.76 m, and the service level of the junction (LOS) on Monday and Sunday is C (not good). And for the movement of vehicle flow passing at intersection 4 Sakra East Lombok, which indicates the density of vehicles traffic flow is moderate, internal traffic barriers begin to affect speed and drivers still have adequate discretion over their speed and the lane they use on the road.


Introduction
East Lombok Regency is one of the regencies in West Nusa Tenggara Province located in the east of the island of Lombok.East Lombok Regency is also one of the level II regions in West Nusa Tenggara Province whose development is quite rapid in various aspects of life [1].East Lombok District is also one of the transit areas because it has the advantage of being a trade route between Lombok Island and Sumbawa Island, so there is often congestion on certain road sections [2].
Road intersections are the location of traffic conflicts and are also meeting places for vehicles coming from different directions and changing directions, as well as the location of facilities needed for traffic flow.Simpang Empat Sakra is one of the unsignaled intersections located in East Lombok.The intersection of four Sakra is a confluence of road flows including, North of Jl.Departement Sakra (Jl.Minor), East of Jl.Soekarno Hatta (Jl.Mayor), South of Jl.Departement Sakra (Jl.Minor) and West of Jl.Sangapati -Jl. Soekarno Hatta (Jl. Mayor).At this intersection there are often delays and queues of vehicles at certain hours, because the type of road environment around the Sakra IOP Publishing doi:10.1088/1755-1315/1321/1/012027 2 intersection is a commercial area, this can be seen by the existence of settlements, markets, mosques, village chief's offices, shops, and other shopping centers [3].PTV Vissim is a software that can be used to simulate and model microscopic traffic flows, public transportation, and pedestrians [4].With the road environment around the intersection which is a commercial area, this is the reason researchers use the PTV Vissim modeling method to display results that are following the conditions of the intersection [5].
From this background, the researcher took the title of the research "Performance Analysis of Unsignaled Interchange Using PTV Vissim Software Modeling (Case Study of Simpang Empat Sakra East Lombok)".This research aims to determine the movement of traffic flow at the 4-way Sakra intersections in East Lombok using Vissim software modeling.So that later the intersection on the road section can serve traffic flow optimally and road users who cross the Sakra intersection will feel safe and comfortable.

Interchange
According to Government Regulation Number 43 of 1993 concerning Road Infrastructure and Traffic.What is meant by "intersection" includes crossings, circular intersections, T-junctions (intersection three), intersection four, intersection five, and intersection four with other highways; It does not include the crossing of a plot with a railroad track.In other words, an intersection is a pair or more lanes that intersect with a road, which also includes curbs and curbside facilities.

Unsignaled Interchange
According to MKJI 1997, an unsignaled intersection is one type of intersection that is the confluence of two or more road sections that are not regulated by the Traffic Signaling Device (APILL).

Traffic Management
Traffic management is the process of regulating and using an existing road system to meet a certain interest, without the need for addition, or the creation of new infrastructure [6].Traffic management is applied to solve short-term traffic problems (before the creation of new infrastructure is implemented), or applied to anticipate related traffic problems (for example traffic congestion at the construction stage, etc.)".

Simulation
Simulation is a process of imitation of something real along with the surrounding conditions.The action of performing these simulations generally illustrates the key characteristic properties of the behavior of a particular physical system or abstract system [7].

PTV vissim software a. PTV Vissim software definition
Vissim is a multi-modal microscopic flow simulation traffic software.• Development, evaluation and regulation of transit signal priorities.
• Vissim can be used in various types of signal settings.
• Vissim can be used to evaluate the feasibility and impact of a small town on the urban road network.• A connected area and an area can be quickly analyzed using Vissim.

Place and Time of Research
Place and Time This study is located at the intersection of Sakra East Lombok.The survey is carried out on Monday and Sunday, which will be carried out at peak hours, namely for the morning at 07.00-09.00WITA and the afternoon at 16.00-18.00WITA.For the intersection of Sakra, East Lombok can be seen in Figure 1.

Data Collection
Data is an influential factor and is very necessary to analyze the problems to be discussed.The data to be taken is in the form of primary and secondary data, where the data is in the form of: a.Primary Data Primary data collection is data taken directly from the field including geometric conditions, environmental conditions, side obstacles, types of vehicles, and traffic flow volumes.The methods used in collecting data by making observations in the field to analyze include the following.
• Geometric data of roads

PTV Vissim modeling
Primary and secondary data from field observations that have been obtained, are then input into the VISSIM PTV software.The modeling results will produce 2D and 3D animations that display, namely: traffic volume data, and average delays in existing conditions.

Results and Discussion
The geometric intersection for this research can be seen in Table 1.Determine the name of the road, the number of lanes, and the width of the road based on the circumstances in the field.For highway system can be seen in Figure 2.

Travel Routes.
Determine the route of travel direction from the east, north, west, and south arms at the intersection.
For travel route can be seen in Figure 3.

Grouping of Vehicle Types.
Grouping of vehicle types for MC (motorbikes), LV (light vehicles), HV (heavy vehicles) and UM (non-motorized vehicles).For grouping of vehicle types can be seen in Figure 4.

Vehicle Types
Determine Some parameters contained in this menu are vehicle category, vehicle models, color, acceleration/deceleration, capacity, occupancy, and others.For vehicle types as illustrated in Figure 5.

Vehicle Classes
Clarify vehicle types that have previously combined vehicles based on similar technical driver characteristics based on vehicle types.For vehicle classes can be seen in Figure 6.

Conflik Area
Controlling vehicles so as not to collide with each other and to prioritize which vehicle passes first, can be seen in the following Figure 7.

Vehicle Input
Traffic volume data that has been obtained from the survey results, is then input into Vehicle Inputs based on the results of field surveys on Monday and Sunday.For Monday and Sunday, data input can be seen in Figure 8 and Figure 9.

Output
The results of running the simulation in the Sakra 4 intersection area can be seen in the following Figure 10.Because it uses PTV VISSIM (Student version) The running process can only be run for 10 minutes (600 seconds) and covers a limited area of 1 km.

Existing Conditions
From VISSIM modeling using survey data in the field, the results show that the existing conditions at the Sakra unsignaled intersection, East Lombok are Queue length (Qlen), delay value (VehDelay), and level of service (LOS) show poor value.For Monday's simulation results can be seen in Table 2.

Alternative
The alternative used is to increase the width of the road on Sangapati Street and Soekarno Hatta Street (Major Road), for each lane, which is 1 m each.For alternative simulation results Monday can be seen in Table 4.The results of the output value in existing conditions with an alternative to increasing the width of the road by 1 m on the main road, show the same level of service, namely C with the results of queue length and delays that are not much different.For Alternative simulation outcomes Sunday is seen in Table 5.The results of the output value in existing conditions with an alternative to increasing the width of the road by 1 m on the main road, show the same level of service, namely C with the results of queue length and delays that are not much different.

Comparison of Running Results.
The comparison between existing condition and alternative can be seen in Table 6.Meanwhile, after increasing the width of the road on the main road (major), the results showed a slight decrease in the length of the queue and delay.As for the level of service is still the same, namely C.

Conclusion
After the calculation and discussion of the data collected and analyzed using PTV Vissim software (Student Version) the following inferences can be made: a.The results of the East Lombok Sakra intersection modeling in existing conditions carried out on Monday and Sunday using VISSIM PTV software modeling (Student Version) obtained values on Monday, Queue Length (Qlen) 34.77 m, Tundaan (VehDelay) 19.95 sec/skr.On Sundays, the value of Queue Length (Qlen) is 23.76 m, Tundaan (VehDelay) is 16.68 sec/skr, and the service level of intersection (LOS) on Monday and Sunday is C (not good).b.The movement of the flow of vehicles crossing at intersection 4 Sakra East Lombok which means that the density of vehicles traffic flow is moderate, internal traffic obstacles begin to influence the speed and drivers can still set their speed with sufficient freedom and the road lane used.For a brief period, this situation can still be tolerated.

Suggestion
a.It is necessary to carry out road repairs in the Sakra intersection area of East Lombok for the smooth movement of traffic flow.b.It is necessary to conduct surveys with much higher accuracy so as to get much more accurate results, such as conducting surveys more than one working day a week or surveys for a full week so that the data obtained better represents actual traffic conditions.

Table 2 .
Monday's simulation results.LOS A means very low traffic density at a speed that can be controlled by the driver based on maximum/minimum speed limits and physical conditions of the road.Soekarno Hatta Street (West) gets Qlen value = 58.768621m,Qlenmax = 147, 469503 m, VehDelay average = 147.4695sec/skr,andLOS is C, LOS C means moderate traffic density, internal traffic obstacles begin to influence the speed and drivers can still set their speed with sufficient freedom and the road lane used.For Sunday's simulation results can be seen in Table3.

Table 3 .
Sunday's simulation results.influence the speed and drivers can still set their speed with sufficient freedom and the lane of road used.

Table 4 .
Alternative simulation results Monday.

Table 4 .
Sakra Street (North) gets Qlen value = 18.611282 m, Qlen max = 62.845702 m, VehDelay average = 15.78771sec/skr, and LOS is C. LOS C means moderate traffic density, internal traffic obstacles begin to influence the speed and drivers can still set their speed with sufficient freedom and the lane of road used.Sangapati Street (East) gets Qlen value = 40.226562m,Qlen max = 161.846637m,VehDelay average = 19.48335sec/skr,and its LOS is C. LOS C means moderate traffic density, internal traffic obstacles begin to influence the speed and drivers can still set their speed with sufficient freedom and the lane of road used.Sakra Street (South) gets Qlen value = 0 m, Qlen max = 0 m, average vehdelay = 5.317204 sec/skr, and its LOS is A. LOS A means very low traffic density at a speed that can be controlled by the driver based on maximum/minimum speed limits and physical conditions of the road.Soekarno Hatta Street (West) gets Qlen Value = 36.206669m, Qlen max = 150.282017m, VehDelay average = 14.98896 sec/skr, and its LOS is B, LOS B means steady flow with moderate traffic volume and speed begins to be limited by traffic conditions.

Table 5 .
Alternative simulation results Sunday./skr, and its LOS is A. LOS A means very low traffic density with a speed that can be controlled by the driver based on maximum/minimum speed limits and physical conditions of the road.Soekarno Hatta Street (West) gets Qlen Value = 54.95205m, Qlen max = 145.950398m, VehDelay average = 14.07058 sec/skr, and its LOS is B, LOS B means steady flow with moderate traffic volume and speed begins to be limited by traffic conditions.

Table 6 .
Comparison of running results.From the Table6.above we can find out the highest value in the Vissim PTV modeling, namely on Monday with an average queue length (Qlen) of 34.77 m, Maximum queue length (Qlen max) of 157.84 m and Delay (VehDelay) of 19.95 sec / skr.