Demonstration of Possibilities to Introduce Semi-actuated Traffic Control System at Dhanmondi Satmasjid Road by Using CORSIM Simulation Software

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1 Paper ID: TE International Conference on Recent Innovation in Civil Engineering for Sustainable Development () Department of Civil Engineering DUET - Gazipur, Bangladesh Demonstration of Possibilities to Introduce Semi-actuated Traffic Control System at Dhanmondi Satmasjid Road by Using CORSIM Simulation Software M. S. Mamun 1, A. M. Shafiq 2, M. R. A. Khan 3 and M. R. Habib 4 Abstract Traffic on most of the roads in Dhaka city are controlled by traffic polices or poorly designed pre-timed signals. Pre-timed signal is definitely better than the manual control. However, pre-timed control tends to be inefficient at isolated intersections where traffic arrivals are random or varies over the time. In Dhaka, many major roads are crossed by minor roads. Traffic volumes on minor roads are relatively low during off-peak period. Therefore, if traffic signals are designed based on peak-period traffic count data and operate as pre-timed system, the drivers on major roads have to wait at signal watching wasted green on the minor roads. Semi-actuated control is the most suitable for this type of places where minor roads cross major roads and traffic volumes vary over the time. Semi-actuated control uses detection only for the minor movements at an intersection. The phases associated with the major-road through movements are operated as "non-actuated". Also, relative to pre-timed control, it reduces the delay incurred by the major-road through movements (i.e., the movements associated with the non-actuated phases) during periods of light traffic. In this research, attempt has been taken to see how the performances of Satmasjid Road can be improved by introducing semi-actuated traffic control system. The road network is modeled in CORSIM simulation software and the performance measures are obtained from the simulation runs. Keywords: CORSIM; pre-timed; semi-actuated; signal timing; traffic control; traffic simulation. 1. Introduction Traffic congestion is a common scenario on most of the roads in Dhaka city. This is due to the fact that there is not sufficient area devoted to road use, no rapid transit system, total absence of efficient signal control system, etc. The congested situation prevails almost all the day. A recent study reveals that the average speed at Mirpur road (a major arterial road) is 15 to 17 kilometer per hour during peak period (Monayem, 2001 [1]). We cannot increase the roadway or implement rapid transit system in short-term, however, we can improve traffic operating condition by introducing appropriate signal controlling systems at the intersections. In this research Dhanmondi Satmasjid road has been selected as a test road to see how traffic operating condition of this road can be improved with the help of better signal controlling system. Dhanmondi Satmasjid road is an important road in Dhaka city, which is poorly operated and managed. The traffic is controlled manually by traffic polices, although traffic signals are present at some places as most of the time these signals remain deactivated. Therefore, traffic is moving without discipline and causing extra congestion. It is predictable that with the appropriate signal timing setting at the intersections along this road, traffic operating condition of this road will be improved. However, if the signals are designed as pre-timed signal controller based on peak-period demand, the operating condition might not be the optimum during off-peak period as many minor roads cross this road at different points. Semi-actuated control is the most suitable for this type of places where traffic volumes vary over the time; specially, traffic volumes at minor roads are relatively low during off- 1 Associate Professor, Ahsanullah University of Science and Technology, smamun93@hotmail.com 2 Graduate, Ahsanullah University of Science and Technology, amshafiq9111@gmail.com 3 Graduate, Ahsanullah University of Science and Technology, rkhan.tomal@gmail.com 4 Graduate, Ahsanullah University of Science and Technology, souravislam08@gmail.com

2 747 peak period. Semi-actuated control uses detection only for the minor movements at an intersection. The phases associated with the major-road through movements are operated as "non-actuated". Also, relative to pre-timed control, it reduces the delay incurred by the major-road through movements (i.e., the movements associated with the non-actuated phases) during periods of light traffic. In this research attempt has been taken to evaluate the performances of Dhanmondi Satmasjid road under semi-actuated controlling system. The whole analyses are performed in CORSIM simulation software. At first the detailed analyses of the Dhanmondi Satmasjid road during peak hour based on the existing condition are carried out. After that the analyses of the whole network are carried out by setting optimum signal timing to the intersections to observe whether the performance can be improved by using pre-timed control. After the completion of the peak hour analysis, further analyses are done using the data of the off-peak hour considering the same signal timing used in the peak-hour to see how efficiently the intersections perform. This includes both the pre-timed and semi-actuated control. 2. Literature Review The first study on road network planning for Dhaka was prepared in 1959 by the Dhaka Improvement Trust (DIT), covering roughly 830 square kilometers are with a population slightly exceeding 0.5 million. It provided a detailed plan for future construction of roads in the metropolis. Dhaka s first comprehensive urban transport study, the Dhaka Integrated Transport Study (1993) was commissioned by the Government of Bangladesh in (and conducted under the Planning Commission and UNDP) and reported in In order to alleviate traffic congestion and improve transportation system, several studies have been conducted for Dhaka city. The Strategic Transport Plan (2004) is the most important among them. The STP was commissioned by the Dhaka Transport Coordination Board (DTCB) from the Louis Berger Group and completed in It serves as the current basis for urban transport planning for Dhaka. The STP aimed to survey existing conditions, develop transport strategies for the future and assist in encouraging preferred land use development. The STP study was focused predominantly on developing strategies for building new infrastructures, including rail transit, bus rapid transit and highway development. Most of the transport studies in metropolitan Dhaka were related to the transport inventory and traffic management. Some of them dealt with mass transit system in the metropolitan area. There had been no major study dedicated to solution of traffic congestion using simulation software. However, using simulation software is not new in Western world. Many research works have been performed on traffic simulations. Prevedouros and Wang (1998) [2] simulated a large integrated network to compare INTEGRATION, CORSIM and WATSim. Mystkowski and Khan (2000) [3] examined queue length as measure of effectiveness at signalized intersection by using CORSIM, TRANSYT-7F, and SIGNAL94, PASSER II-90 and SYNCHRO3. Kim and Benekohal (2005) [4] compared control delays obtained from CORSIM simulation to the Highway Capacity Manual (2000). Rilett et al. (2000) [5] compared low-fidelity TRANSIMS and high-fidelity CORSIM highway models with ITS data. Simulation software is also used with signal controlling system (Perrin et al. (2001) [6]; Park et al. (2000) [7]). Many researchers used simulation software in access management, operation of roundabouts, operation of public transport, etc. (Yang and Zhou (2004) [8]; Chien et al. (2000) [9]; and others) As semi-actuated signal design has never been implemented in our country, it is appropriate to perform a full study on semi-actuated signal control using CORSIM software in Dhaka City. 3. Data Collection Dhanmondi Satmasjid road is almost North-South directional connected to Asad Avenue at north side

3 748 and Dhanmondi Road# 2 at south side. There are many offices, schools, colleges, universities, restaurants, shops, etc. along this road. A long queue of traffic is a common scene almost all the time during the peak period. But the worst situation are seen (except any special occasion) in the noon when the schools break (12.00 pm to 2.00 pm) and in the afternoon when the offices end (4.00 pm to 7.00 pm). The flow of the vehicles and pedestrians reach to its maximum of the day at those times. It is also found that the minimum flow of traffic at off-peak hour occurs in the morning (9.00 am to am). Traffic flow at that time period is moderate and traffic congestion can hardly be seen. Among the three intersections within the study area, Star Kabab intersection and Ibn Sina intersection get more congested in the peak period than Dhanmondi 4/A intersection. Also the traffic flow through the minor roads are almost nil during the off-peak period. Peak and off-peak period traffic volumes at three intersections are provided in Tables 1. Table 1. Traffic volume at three intersections (PCU/hr) Intersection Time South West North East Star Kabab Ibn Sina Dhanmondi 4/A Peak Off- Peak Peak Off- Peak Peak Off- Peak Model Building The network is developed in CORSIM simulation software using basically nodes and links. The length of the network and other measurement i.e length, width, side-friction, number of lanes etc used here are obtained from field surveys. The developed model is shown in Fig. 1. Fig. 1. CORSIM simulation model After building the network, properties of intersections (nodes, turn movement relative turn volume percentages data, lane alignment, stop line, etc.) and signal timing are provided. In pre-timed control system (Fig. 2(a)), green time and yellow time for each phase at every intersection are provided; and in semi-actuated control system (Fig. 2(b)), min-green, max-green, yellow and split % are provided.

4 749 Fig. 2(a). Pre-timed controller Fig. 2(b). Semi-timed controller 5. Network Analyses and Results 5.1. Existing condition analysis (Peak period) During reconnaissance survey it was observed that there was no effective and working traffic control system present at Star Kabab, Ibn Sina and Dhanmondi 4/A intersections, only traffic polices manually operate and control the traffic stream. It was found that traffic police used to allocate 60 sec for each phase at every intersection during peak hour. Using the exiting existing traffic movement pattern and time allocation, the signal timings were set in CORSIM and model was run for 3600 sec. Network wide average statistics of the whole network during peak period is provided in Table 2. Table 2. Performance measures of the whole network (Existing condition) Network-wide Average Statistics Total Vehicle- Mile 1850 Total time (vehicle-hours) 170 Total time (Minutes/Mile) 5.5 Delay time (Vehicle-Hours) Delay time (Minutes/Mile) 3.6 Average Speed (Mph) Improved condition analysis (Peak period) From the existing condition analysis we have found that there are heavy traffic congestions at all the three major intersections within the study area. Therefore, optimum signal timings were set at every intersection in CORSIM model keeping the traffic volume, lane number, lane width and length data same as used in existing network analysis. In this improved model we assigned pre-timed control system having same cycle length of 180 sec. with three phase movements at each intersection. Maximum 110 sec green time is allocated for the major approach along with 12 sec green time for the critical turning (right turning) and 46 sec green time is allocated for the side roads. With these adjustments to the signal timing we further analyzed the model in CORSIM to identify the improvement of traffic operation in the network. Network wide average statistics of the whole network after the improvement is provided in Table 3.

5 Table 3. Performance measures of the whole network (Improved condition) Network-wide Average Statistics Total Vehicle- Mile 1862 Total time (vehicle-hours) 144 Total time (Minutes/Mile) 4.66 Delay time (Vehicle-Hours) Delay time (Minutes/Mile) 2.6 Average Speed (Mph) Network analysis (Off-peak period) If the signals along the road operate as pre-timed (designed with peak period traffic volumes), it is expected that there will not be any problem in the network during off-peak period; however, the performance will not be optimum during off-peak period as the traffic volume on minor roads will be low. In this situation the system might perform better under semi-actuated system instead of pre-timed system. Therefore we performed the analyses with the off-peak period traffic volume for both the pretimed signal timing and semi-actuated signal timing. Network wide average statistics of the whole network under different systems are provided in Table 4 and Fig. 3. Table 4. Performance measures of the whole network during off-peak period Network-wide Average Statistics Pre-timed Semi-actuated Total Vehicle- Mile Total time (vehicle-hours) Total time (Minutes/Mile) Delay time (Vehicle-Hours) Delay time (Minutes/Mile) Average Speed (Mph) Comparison between Pre-timed and Semi-Actuated Control for Dhanmondi Satmasjid Road Total Time(Min/mile) Delay time(min/mile) Avg. speed(mph) 5 0 Pre-timed Actuated Fig. 3. Performance measures under pre-timed and semi-actuated systems

6 Conclusion and Recommendation Dhanmondi Satmasjid road is an important busy road in Dhaka city. But its operating performance has been degraded and still being degraded due to various reasons. Traffic controlling system is one of them. In this paper we showed that operating condition of this road can be improved by setting appropriate signal timing at the intersections. We found that the average delay time had reduced to 2.6 Min/mile from 3.6 Min/mile and average speed had increased to Mph from 10.9 Mph after implementing better pre-timed signals. However, the performance of pre-timed signals based on peak hour traffic volume might not be the optimum during off-peak hour as Dhanmondi Satmasjid road is crossed by many minor roads and the traffic volumes at those minor roads are relatively low and vary over time. Therefore, we analyzed the network for off-peak hour traffic volumes with both pre-timed and semi-actuated signals. We found that during off-peak hour the average delay time was 2.9 Min/mile using pre-timed control system, which was reduced to 2.0 Min/mile after implementing semi-actuated traffic control. The speed also increased from 13.6 Mph to 14 Mph after the implementation of semi-actuated traffic control. The improvement due to semi-actuation obtained in this research is not very significant due to the fact traffic volume on most of the roads are over their capacities and off-peak hour traffic volumes are not significantly low compare to peak hour traffic. Even though, as improvement found, we can say that there is a scope to achieve better outcome of the semi-actuated traffic control system. Semi-actuated traffic control system should be tested for other roads in Dhaka, so that this system can be implement in near future. 7. References [1] Monayem, M.A. Evaluation of Traffic Operation Conditions on Two Urban Arterials in Metropolitan Dhaka, M.Eng. Thesis, Department of Civil Engineering, BUET, [2] Prevedouros, P. D., and Wang, Y. Simulation of freeway/arterial network with CORSIM, INTEGRATION, and WATSim, Proc., 78th Annual Meeting, Transportation Research Board, Washington, D. C., [3] Mystkowski, C., and Khan, S. Estimating Queue Lengths by Using SIGNAL94, SYNCHRO3, TRANSYT-7F, PASSER II-90, and CORSIM, In Transportation Research Record 1683, [4] Kim, S., and Benehohal, R. F. Comparison of Control Delays from CORSIM and the Highway Capacity Manual for Oversaturated Signalized Intersections, Journal of Transportation Engineering, ASCE, [5] Rilett, L. R., Kim, K., and Raney, B. A Comparison of the Low Fidelity TRANSIMS and High Fidelity CORSIM Highway Simulation Models Using ITS Data, In Transportation Research Record1739, TRB, National Research Council, Washington, D. C., [6] Perin, J., Martin, P. T., and Hansen, B. G. Connecting SCOOT to CORSIM: Real-Time Signal Optimization Simulation, The 27th Annual Conference of the IEEE Industrial Electronics Society, [7] Park, B., Pourhail, N. M., and Sacks, J. Assessment of Stochastic Signal Optimization Method Using Microsimulation, In Transportation Research Record 1748, [8] Yang, X. K., and Zhou, H. G. CORSIM-based simulation approaches to evaluation of direct Left turn versus Right turn plus U-turn from driveways, Journal of Transportation Engineering, ASCE, [9] Chien, S. I., Chowdhury, S.M., Mouskos, K. C., and Ding, Y. Enhancement of CORSIM Model in Simulating Transit Operations, Journal of transportation Engineering, 2000.