DESIGN OF VEHICLE ACTUATED SIGNAL FOR A MAJOR CORRIDOR IN CHENNAI USING SIMULATION

Transcription

1 DESIGN OF VEHICLE ACTUATED SIGNAL FOR A MAJOR CORRIDOR IN CHENNAI USING SIMULATION Presented by, R.NITHYANANTHAN S. KALAANIDHI Authors S.NITHYA R.NITHYANANTHAN D.SENTHURKUMAR K.GUNASEKARAN

2 Introduction Most of the cities in India have fixed time signal settings and it is operated manually during morning and evening peak hours. Manual operation is adopted assuming that the traffic police personnel would judge the length of queue in each arm and would apportion green time for vehicles to clear the intersection based on queue length. Manual control does not offer considerable benefits in reducing the delays of all vehicles. Vehicle actuated (VA) equipped with Virtual Loop detectors and the necessary control logic to respond to the demand placed on traffic movements to be serviced.

3 Benefits of Vehicle Actuated Signals Handle the random fluctuations in the traffic condition Works on the real time information Vehicle presence is conveyed to the controller through the detectors placed for the various movements Reduce the overall delays and optimizes the signal timings at the intersection Especially effective at multiple phase intersections.

4 Need for Vehicle Actuated Signals Wasted green Queue forming When demand varies significantly from time to time, either green time is wasted or queue forms. To avoids these variation in arrival vehicle actuated signal are necessary Vehicle actuated signals with varying phase time which automatically varies the phase time helps in improving the intersection function

5 Real Time Detection of Traffic Video cameras with virtual loop detectors are able to detect the presence of vehicles. This virtual loop is used to place at nearby intersection and also for advance detection. Multiple detection zones per lane possible to cover a larger area Wide Angle Narrow Angle

6 ADVANCE DETECTION STOP BAR DETECTION Length of Detection Zone depends on Permitted speed

7 Vehicle Actuated Signals Actuated Control may be programmed to accommodate Variable Phase Sequence Variable Green time for each phases Variable cycle length, caused by variable green time

8 Actuated control and controllers The cycle length, phase splits, even the phase sequence may vary from cycle to cycle. Semi-actuated control Detection only on minor side-street approaches; green remain on the main until a call for service on the side street is registered. Full-actuated control All approaches have detectors; equal importance of the direction of traffic; for relatively isolated intersections; Volume-density control Basically functions like full-actuated control; good for high-speed approaches (>= 45 mph); Has extra features to adjust initial timing and reduce the gap extension during green extension time

9 Detection type Point detection ( passage type) A single detector is placed for each approach lane to be actuated. The detector relays information as to whether a vehicle has passed over the detector. Area detection ( presence type) Generally used in conjunction with volume-density controllers. The importance is placed on the existence of a vehicle (s) in the detection area. They count the number of vehicles stored in the detection area.

10 Actuated control features and operation Minimum green time (Initial green + unit extension) Passage time interval Maximum green time Recall switch (unless the subsequent phase has the recall on green remains to the previous phase unless demand exists) Yellow and all red

11 Simulation Model Building Model Building The processes and steps involved Step 1 : Sections on the road network, Step 2 : Vehicle types and classes were used to define the vehicle parameters. Step 3 : Speed distributions defined from observed data. Step 4 : Traffic compositions created for entry points to the network. Step 5 : Placement of routing decision points in the network. Step 6 : Placement of signal positions and signal timing in the road network.

12 STUDY AREA Anna Salai, major arterial road in Chennai city, a stretch of 3.1 km was selected as study stretch. With the development of educational institutions, commercial activities the corridor have encountered problems such as traffic congestion, road accidents, and also air pollution.

13 Intersection volume in vehicle/hour S.No Intersection Volume in vehicles/hour 1 Thiruveka Junction Smith Road Junction Spencer Junction Wellington Plaza Junction Walajah Road Junction 11624

14 Video graphic survey at Spencer intersection Two video Cameras were installed on a tall building at Spencer intersection to measure the volume and queue length in the morning from 7.00A.M to 12.00P.M

15 Travel Time along Study Corridor The survey was conducted during morning peak hour and evening peak hour. The GPS instrument was used to measure the travel time and delay for the entire stretch. The travel time on Mount Road from (Thiruveka junction to Walajah junction) was around 110 seconds in peak hours and around 87 seconds when travelling in opposite direction Study Stretch Morning Peak Hour (km/hr) Thiruveka to LIC LIC to Thiruveka

16 Travel Pattern in the Study Stretch The travel pattern has been arrived from the turning movements data. Totally 12 movements were considered. The in out traffic is given in the form of O-D Matrix OD projection for the study stretch Total Total

17 SCENARIO FORMULATION The scenarios were formulated to study the performance of the study stretch and to identify the best option. Scenario1: Existing Condition with fixed time signal Scenario 2: Vehicle actuated Programming Scenario 3: Co ordinate fixed time signal

18 Spencer Junction Junction Model Validation To validate the model correctly comparisons were made exiting volume with the observed volume Number of Vehicles / hour Street Vehicle Movement Simulated Condition Existing Condition Left Gemini Road Through Total Left EA Road Right Total Left Benny Road Right Total Left LIC Road Through Right Total Total The validated model was within the tolerance of the validation criteria (10%).

19 Behavior of Scenario 1 Existing Condition Scenario 1 gives the existing condition of study area.. Fixed time signal settings preferred for morning peak hour was used.

20 Behavior of Scenario 2 Vehicle Actuated Signal Scenario 2 gives the corridor performance with vehicle actuated signals Variable cycle time / variable phase timing model was attempted for the intersections.

21 Cond., Defining vehicle detection zone by placing the two detectors for each lane in each approach. The detectors sensed the presence/absence of vehicles in between them. Towards Gemini Detector Exit Detector Entry Towards LIC Thiruveka Junction

22 Function of VAP

23 Behavior of Scenario 3 co ordinate signal The cycle time of critical intersection was adopted for all intersections and co ordination for movement of vehicles towards Parrys was attempted. The offset timing for the signals assuming vehicle speed of 30km/hr was considered for co ordination.

24 RESULTS AND DISCUSSIONS Comparison of VA with fixed timings The individual intersection performance shows significant reduction in delay to about 28% if vehicle actuated signals are adopted. The reduction in intersection delay for scenario 2 was from 20% to 39% when compared with scenario 1. At the critical intersection i.e., Spencer intersection the delay reduction was 39%.

25 RESULTS AND DISCUSSIONS Comparison of Fixed time signals with coordinated fixed timing signals The cycle time of the signals was assumed to be 140seconds, i.e., the cycle time required for critical intersection. The speed of the traffic flow was assumed as 30kmph. On Co-ordination of signals an average 8% reduction in delay is possible when compared to scenario 1. Similarly if Co-ordination of Vehicle actuated signals is attempted, reduction in delay could be realised.

26 CONCLUSIONS Vehicle actuated signals is proposed to replace the existing fixed time signals. With implementation of Vehicle actuated signals 28% delay reduction is possible. Further reduction is possible if a Co-ordination of Vehicle actuated signal is attempted. With the development in technology like Virtual loop Camera it is possible to erect Vehicle actuated signals.

27 THANK YOU