Comparison of dilemma zone length for car drivers between PTV Vissim and visual observation

. There is a zone known as the dilemma zone located on each arm of a signalized intersection, where in this zone, the vehicle at the start of the yellow light is hesitant to stop safely, before the stop line or continues past the intersection with the start of the red light. In the dilemma zone, there is a decision to go through the intersection at the risk of colliding with a car coming from the other arm, or a decision to stop suddenly which might result in a rear-end collision. The longer the dilemma zone, the higher the risk that the driver will pass through the intersection. Therefore, the purpose of this study is to compare the results between visual observations and PTV Vissim results regarding the yellow light dilemma zone for 3 seconds at the 4-arm intersection for car drivers. using the Gaziz method. The dilemma zone for passenger cars from visual observation compared to PTV Vissim simulation has a result of 55% longer with a distance of 6,15m to 28,65 m, where PTV Vissim shows a distance of 2,79 m to 11,25 m. This distance is based on the denser traffic situation during peak hour.


Introduction
Traffic congestion is a situation where the traffic flow exceeds the capacity of the road resulting in queues of vehicles [5,6,9].Road intersections are accident-prone locations for traffic [14].Intersection safety and drivers' behavior are strongly interrelated [12] One of the most critical elements at signalized intersections is the design of detection equipment and timing of change and clearance intervals [8].Undoubtedly everyone has observed at some time or other the occurrence of a driver crossing an intersection partly during the red phase of the signal cycle [1].When a yellow light comes on at a signalized intersection, one important question for drivers is whether to go or stop.There is a zone known as the dilemma zone that is located on each arm of a signalized intersection, where in this zone, the vehicle at the start of the yellow light turns feels hesitant to stop safely before the stop line or continue past the intersection with the start of a red light.[15].Road crossing decisions depend on the surrounding traffic conditions, pedestrian characteristics, and external environmental factors [4].The dilemma zone is defined Corresponding author: eduardi@binus.ac.id as the area where a driver approaching a signalized intersectio 1 n must decide whether to continue or stop at the start of a yellow indication [2,7].In the dilemma zone, there is a decision to go through the intersection at the risk of colliding with a car coming from the other arm, or a decision to stop suddenly which might result in a rear-end collision.The longer the dilemma zone, the higher the risk that the driver will pass through the intersection [16].The dilemma zone, also called the decision zone in other literature, is an area of high-speed signalized intersections, where drivers face hesitation to stop or pass at a yellow turn [11].A large number of studies have been conducted to find the best way to prevent oncoming vehicles from getting stuck in the dilemma zone.Where the study introduces the idea of a yellow light dilemma zone and explains why such zones exist [16].PTV Vissim is a traffic simulation tool or software for traffic engineering, transportation planning, signal timing, public transport, and microscopic urban planning purposes [3,10,13].Therefore, the purpose of this study is to present a comparison of the results between visual observations and PTV PTV Vissim

Methodology
The location of the study area analyzed is 4-arm intersection which is located at Arteri Permata Hijau Road, West Jakarta shown in Figure 1.In collecting traffic volume data it is carried out manually with the help of cameras and cellphones directed to the road with the help of a tripod.Traffic data is managed every 2 hours, in the morning during peak hours (07.00 -09.00)WIB, and during off-peak hours (09.00 -11.00)WIB.

Intersection geometry
The correlation between intersection geometry and the dilemma zone can be significant.The larger intersections tend to have longer dilemma zones, as vehicles traveling at higher speeds require more time to come to a stop.WA is specifically related to the width of the roadway or lanes to approach the intersection.WE are the effective width of an intersection refers to the usable space available for vehicles within the intersection area shown in Figure 2. The intersection geometric study location is shown in Table 1.

Driving behaviour
Driving behavior plays a crucial role in the existence and impact of the dilemma zone at signalized intersections.Driver behavior is one of the Vissim parameters that characterize microscopic traffic simulations.Each characteristic of the driver's behavior is adjusted according to actual conditions so that the Vissim representation is accurately shown in Table 2.There is a difference between the results of driving behavior in Vissim and visual observations.In visual observation, the driver can consider factors such as speed, traffic conditions, weather conditions, and road signs.In Vissim, drivers make decisions based on predefined input parameters, and they may not have the ability to consider these factors in real situations.

Traffic flow condition
During peak hours, the probability of the occurrence of a queue length dilemma zone will be different during off-peak hours.This is because when vehicles approach the intersection, the speed will decrease during peak hour (dense) compared to off-peak hour.This situation can certainly affect the driver's decision-making as well as the length of the dilemma zone.This must be proven by further research.

Intergreen period and loss time
The intergreen is a function of the speed and distance from the stop line for each vehicle that will clear the intersection and vehicles that will enter the intersection area to the point of conflict shown in Figure 3.

Effective Green Time = Green Time -Start Lost +
End Gain The loss time would be while the total lost time can be calculated as the sum of the inter-green periods.
The length of yellow time on urban traffic signals in Indonesia is usually taken to be 3.0 seconds [5].

Yellow sign
The yellow signal in an intersection is the period following the green signal that warns drivers of an impending change in the right-of-way assignment.The yellow sign influences the length of the dilemma zone, the longer the duration of the yellow light, the longer the length of the dilemma zone.So, the way to address any potential limitations to the length of the dilemma zone is by planning the right duration of the yellow light, because it is very important in minimizing the length of the dilemma zone and increasing traffic safety at intersections.Yellow light duration must take into account factors such as the average vehicle speed, the braking distance required, and the characteristics of the intersection itself.This gives drivers more time to decide whether to stop or continue through the intersection when a yellow light appears.

Cycle time
The cycle time at this signalized intersection is obtained by calculating the red, yellow, and green lights at each that will be used as a study location shown in Table 3 and Table 4.

Vehicle volume
Traffic volume has a value that can be calculated using traffic expressed in Passenger Car Units (SMP) and then converted by multiplying the Passenger Car Equivalence (EMP) shown in Table 5.

Speed and deceleration
The data are taken when the yellow signal is 30 meters from before the traffic light shown in Table 6.To find out the results of the second speed that is obtained from the field, it is converted to m/sec obtained using the following formula: To find out the deceleration whose data has been obtained in the field, use the following formula:

Reaction time
Reaction time is obtained from the reaction of the driver when the light is green, and when the light shows green, seen from the reaction of the driver running the vehicle shown in Table 7.

Capacity
Capacity is the ability of an intersection to accommodate the maximum traffic flow per unit of time expressed in green pcs/hour.The capacity at the intersection is calculated for each approach or lane group within an approach shown in Table 8.To find out the capacity of the intersection in the table above, use the following formula:

2.11
Gazzi Method Dilemma Zone Gazis, Herman, dan Maradudin (GHM) define the dilemma zone based on the difference between the distance from the stop line to the closest vehicle that can atop where is the minimum distance from the driver's vehicle to the stop line that the driver considers to stop his vehicle at a yell to order to stop at the stop line (XC) and the maximum distance the driver considers to the stop line so that the driver on yellow can continue to cross the stop line (XO) from the stop line to the farthest vehicle that can cross the intersection at the start of yellow.Their definition is illustrated shown in Figure 4 and is often referred to as the GHM model.Both of these critical distances are calculated by two equations, namely: This equation to get the distance to stop the vehicle safely: (7) This equation to get the distance when the vehicle goes through the intersection: (8) If the driver does not accelerate the vehicle, then the above equation changes to: (9) This equation to get the length of dilemma zone:

PTV Vissim Traffic Simulation
There are several ways to get the length of the dilemma zone by using PTV Vissim simulation by entering vehicle volume, speed, deceleration / reduce speed area, and changing the yellow time interval.Because there are no tools to get the dilemma zone directly, this experiment was carried out, in which after entering several parameters and already running the simulation, you can find the length of the dilemma zone by measuring on PTV Vissim when running the simulation.

Results and discussion
Table 9 shows the length of the dilemma zone during peak and off-peak hours based on several speed variations.These results were obtained based on the duration of the yellow time of 3 seconds, the perception of reaction time, the deceleration, the vehicle length of 4 m for passenger cars, and the width of the intersection shown in Table 9 and Figure 5.   10.The comparison is illustrated shown in Figure 6 and Figure 7.
The results of the comparison of dilemma zones using the PTV Vissim simulation with manual calculations are several parameters that are compared, wherein the PTV Vissim simulation for deceleration/reduce the speed of the area entered uses the average value of the deceleration that has been obtained from the results of the analysis, by averaging the deceleration 5 a sample of vehicles in each direction at the intersection, where the results are used as a slowdown/reduce speed area in PTV Vissim shown in Figure 8, while for manual calculations enter according to the vehicle, and after comparing the results are not too different, the length of the dilemma zone is obtained.

Conclusion
Based on the results of the comparisons that have been made, the following conclusions can be drawn: The dilemma zone for passenger cars from visual observation result is 55% longer with a distance of

Suggestion
The following are some things that are suggested to be a concern for further research on the research that: To adding a digital display to traffic lights will reduce the dilemma zone for motorists.This digital display that shows the length of time remaining green will help the driver to decide whether to stop the vehicle or continue through the intersection; To compare between cars and motorcycles for dillema zone; To extend the type of intersections such as 3-arm intersection.
The comparison results from dilemma zone length Between Visual Observation of PTV Vissim at Peak Hour and Off-Peak Hour are shown in Table

6 ,
15 m to 28,65 m than PTV Vissim results with a distance of 2,79 m to 11,25 m.This distance is based on the denser traffic situation during peak hours; Based on the results of the dilemma zone analysis using PTV Vissim simulation, it can be said that this simulation is not effective enough to carry out dilemma zone analysis where the results during the simulation are quite different from the calculation or what happened in the field during the research.Several parameters are entered to suit manual calculations such as road width, vehicle speed, reduced speed area, traffic light indication, vehicle volume, and driving behavior.The results obtained after the simulation are different where the yellow light indication when conducting field research gets a 3-second yellow light interval and when entered into the PTV Vissim simulation with a 3-second yellow light interval it is different from what is in the field.

Table 3 .
Peak Hour car cycle time.

Table 4 .
Off-Peak Hour car cycle time.

Table 5 .
Peak Hour and Off-Peak Hour vehicle volume.

Table 6 .
Peak Hour and Off-Peak Hour speed.

Table 7 .
Average reaction time

Table 8 .
Peak Hour and Off-Peak Hour capacity.

Table 9 .
Dilemma Zone during Peak Hour and Off-Peak Hour.

Table 10 .
Comparison result dilemma zone length.