Information and Communication Technology Seminar, Vol. 1 No. 1, August 2005
ISSN 1858-1633 2005 ICTS 101
A PARALLEL ROAD TRAFFIC SIMULATOR CORE
Dwi Handoko, Wahju Sediono, Made Gunawan
Center for Information and Electronics Technology Development, BPPT Jl. M.H. Thamrin No. 8 Jakarta, 10340
Email: dwihinn.bppt.go.id
ABSTRACT
Traffic jam is one of common problem of big cities in Indonesia. One way to reduce the traffic problem is
to obtain accurate traffic rules for each condition of traffic. Here, in order to obtain an optimal traffic rules
a traffic simulator tool is useful. A microscopic road traffic simulator core for simulating road structure and
rules design have been developed by our group. The model for vehicles movement is developed based on a
behavioral model. Simulation is performed based on lane. The core has also the ability to analyze the
vehicle flow rate of the lane. However, since almost traffic rule design requires a large area, a large
computing power for simulation is required; therefore consideration of the simulator should be ale to
perform in parallel in order to decrease the computing time. The program design and the strategy for parallel
porting of the program will be described in this paper. Keywords: Traffic simulator program, parallel
simulation
1. INTRODUCTION
One of common problem of big cities in Indonesia is traffic jam. This problem can be seen almost
everyday in big cities. However, this problem not just finished in the traffic jam problem. This problem may
also arose another problem such increasing energy consumption, since there are much energy loss in the
road because of traffic jam. This problem may also lower the national productivity, since there are many
time losses in the road and many of people get stress because of traffic jam.
An optimum traffic rules such as length of red traffic light time for specific road at specific time is
useful to decrease the traffic jam. However it is not easy to evaluate many variations of traffic rules by try
and error in the field. A traffic simulator is useful in order to get the optimum traffic rules, since many
variations of traffic rules can be applied in the simulation and the result can be obtained in a short
time. We have been developing traffic simulator tools for this purpose [1,2,3]. The developed simulator is a
microscopic road traffic simulator, where it simulates every body i.e. vehicle, traffic light in the
simulation. This approach will increase the accuracy of the simulation [4]. There are several microscopic
traffic simulator prior of this work [4,5,6]. However, the developed simulator is developed for the purpose
of enabling the Indonesian traffic situation. In order to obtain an accurate traffic rule, some
cases need to be verified in a large area. However, simulation of a large area requires a lot of computing
power. Therefore, in order to simulate this large traffic area, a parallel version of the simulator is required.
This paper describes the design of parallel traffic simulator core. This parallel core is an extension of
the previous work of serial traffic simulator core [2].
2. PROPOSED SIMULATION MODEL
We have developed a traffic simulator which the vehicle following simulation flow is as shown in the
Fig. 1. The vehicle moves forward according to the distance to the front vehicle. The vehicle increase,
maintain or decrease the speed according to the prediction time to stop. This model developed based
on actual driver’s behavior, which always predicts the distance to the front and time to stop in order to decide
whether to increase, maintain or decrease the vehicle speed.
Calculate distance with a
max
Get dist. To stop x_stp
with vt
Calculate new dist a
min
Set New Position Set New Speed
If dist. x_stp
Set New Position Set New Speed
time ++
Fig. 1. Vehicle Simulation Flow
The developed road traffic simulator is simulated based on lane of the road. In this way, first, one lane is
Information and Communication Technology Seminar, Vol. 1 No. 1, August 2005
ISSN 1858-1633 2005 ICTS 102
chosen and then behaviors of the lane members vehicle etc are simulated. This process is repeated
for all of the lane. A lane is defined as a one-direction graph. A road may consist of several lanes. Figure 2
shows a road that consists of two lanes.
In the developed simulator, the method of choosing a lane from the lane list is based on lane
distance number. Here, each lane is defined to have a distance number. A distance number means the
distance of the lane from the source of vehicle. Source of vehicle is a vehicle-generator that is placed
in the boundary area of simulation to generate vehicle to be simulated. Figure 3 shows an example of lanes
with its distance numbers.
Veh. Source
Distance = 1 Distance = 2
Distance = 2 Distance = 2
Distance = 4 Distance = 3
Distance = 5
Fig. 3 Distance number of lanes
. The entire simulation is performed in the following
steps: 1. Vehicle generation
2. Took a lane with distance number = DMAX maximum distance number
3. Simulate every body related to the lane 4. Choose another lane with the same distance
number, go to step 3. 5. If all lane with same distance number has
been simulated, decrease the distance number, choose one lane and go to step 3
6. If all lanes have been simulated, increase the simulation time, go to step 2.
These steps are shown in Fig. 4.
3. PARALLELIZATION STRATEGY
