Design of Traffic Intersection

Abstract

Transportation contributes to the economic, industrial, social and cultural development of any country. Traffic congestion is a major problem due to the unexpected growth of private vehicles in a country. The intersection is the most important part in any highway, Because the traffic congestion is due to this. An intersection is defined as the general area where two or more highways join or cross, within which are included the roadway and roadside facilities for traffic movements in that area. In this project, an intersection at Tirupur was taken for analysis. All the necessary traffic parameters of the intersection was collected and analyzed. The intersection is designed as per IRC standards ensuring safe and efficient movement of vehicles at intersection

Introduction

I. INTRODUCTION

An intersection is a location where two or more roads meet. The cars can turn in this location in many directions to go to their intended destinations. Its major job is to direct moving cars in the right direction. Any highway's traffic crossroads are difficult to navigate. This is due to the desire of vehicles travelling in opposite directions to share a place simultaneously. The same place is also sought after by pedestrians for crossing. At a junction, drivers must make a split-second decision while taking into account their path, the intersection's design, the speed and direction of other cars, etc. A slight lapse in judgement can result in catastrophic accidents. Also, depending on the type, geometry, and type of control, it creates latency. Traffic flow in general is dependent on the intersections performance. The road's capacity is also impacted. Hence, the analysis of crossings is crucial for traffic engineers, especially in metropolitan scenarios, from both an accident and a capacity standpoint.

II. OBJECTIVE OF THE STUDY

The objectives of this study are,

1. To select a congested intersection in an urban area.
2. To collect appropriate data for the intersection by using volume count survey.
3. To analyze the collected data.
4. To describe several fundamental aspects of intersection design including managing multimodal conflicts, sight distance, layout etc.
5. To provide general principles, considerations and design guidelines for key intersection components.
6. To suggest suitable measures for intersection to control the flow of vehicles.

III. CODE BOOK REFERENCE

INTRODUCTION

The literature review presented below is aimed to gather knowledge about design of traffic intersection and details of necessary design elements.

IV. IRC GUIDELINES

IRC 64: 1990 “Guidelines for Capacity of   Road in Rural Areas”. It gives the guidelines for selecting a PCU value for different vehicles. The result of the presence of slow-moving vehicles in the traffic stream is that it affects the free flow of traffic.

IRC 65: 1976 “Recommended Practice for Traffic Rotaries”. It gives the guidelines for selecting a rotary type of intersection. Because of the limitation, rotaries are not suitable for every location.

IRC SP-41(1994): “Guidelines for the design of At-grade intersections in Rural and Urban areas” and also used for PCU values. These guidelines are intended to assist those who are required to design or improve at-grade intersections in rural and urban areas. It takes into account the mixed and heterogeneous traffic conditions prevailing in India.

V. METHODOLOGY

A. Study Area

An intersection in Pushpa theatre, Tirupur City was chosen as a study area for this study .It is a four-way skewed intersection type junction since the roads intersect at an angle less than 75 degree. The traffic flow is heavy in this area & mainly composed of buses & two wheelers because of presence of railway station and also schools, Colleges that are located nearby. In order to minimize traffic congestion, traffic delay & reduce risk of accident in that area it was planned to design the intersection and regulate the traffic flow in an orderly way. The satellite image of the intersection was shown in Fig 3.2.

B. Data Collection

Types of data collection

Video graphic surveying

Traffic volumes can be counted by viewing videotapes recorded in a camera collection at the site. A digital clock in the video image can prove useful in noting time intervals. Video recording was done on 03/08/2016 Wednesday from Morning 8.00 AM to Evening 6.00 PM. The traffic count was done manually by looking at the videos for every 15 minutes from start to end of the video graphic data collected. This counted data was used for PCU value findings and peak hour calculation based on which the capacity of the intersection was calculated. Fig 4.1 and Fig 4.2 shows the image of the Pushpa theatre junction taken from video graphic surveying.

C. Counting Procedure

The movement of vehicles in the intersection was counted for every 15 minutes interval from the recorded video. The flow of vehicles in each directions are noted separately. The counted vehicles are classified as per IRC SP41:1994. The flow of vehicles in different directions counted from the video graphic survey was given in the Annexure I.

D. Data Analysis

Volume Count Analysis

The volume count analysis was carried out as below.

VI. PASSENGER CAR UNIT

Table 5.1 PCU Values for Different Vehicles

VII. PROCEDURE FOR CALCULATING PCU VALUES

A. Peak Hour

Maximum PCU values obtained in the one hour is called peak hour. The PCU values for each one hour from morning 8.00 a.m. to evening 6.00 p.m. were calculated. The maximum PCU value was obtained as 7794 PCU/hour at morning for 10.15 A.M to 11.15 A.M. Therefore this hour was considered as the peak hour of the study. The peak hour graph is shown in Fig 5.1.

B. Peak Hour Procedure

Peak hour was calculated by splitting the time 8.00 a.m. to 6.00 p.m. into one hour duration in every 15 minutes (For e.g., 8.00 to 9.00, 8.15 to 9.15). The PCU values for every splitted hour was calculated by summing up all the 15 minutes PCU values in that hour (i.e., PCU values of 8.15 to 8.30 + 8.30 to 8.45 + 8.45 to 9.00 + 9.00 to 9.15).

 Finally, the peak hour as 10.15 a.m. to 11.15 a.m. was arrived. The Total PCU values per hour for individual roads is shown in Fig 5.2 and their percentage of vehicle composition is shown in Fig 5.3.

Note

The Table 5.2 shows 15 Minutes PCU values for individual roads. FLYOVER road reaches the maximum PCU values among the four roads. This show that the amount of traffic conflicts mainly occurs at this critical point only.

Table 5.3 PCU/Hour Value for Individual Roads

C. Design Of Rotaries

Introduction

Rotary intersections or roundabouts are special form of at-grade intersections laid out for the movement of traffic in one direction around a central traffic island. Essentially all the major conflicts at an intersection namely the collision between through and right-turn movements are converted into milder conflicts namely merging and diverging. The vehicles entering the rotary are gently forced to move in a clockwise direction in orderly fashion. They then weave out of the rotary to the desired direction. Fig 6.1 shows the existing layout of the Pushpa theatre intersection at Tirupur.

E. Result Analysis Design Details Of An Intersection

The design elements include design speed, radius at entry, exit and Central Island, weaving length and width, entry and exit widths. In addition the capacity of the rotary can also be determined by using some empirical formula. Some important design elements in Perumanallur Road, College Road, Railway station road, Fly-over Road are shown in the following Tables(Table 7.1 to Table 7.4)

Table 7.1 Perumanallur Road

Conclusion

A. Recommendations The following recommendations are suggested from this study to improve traffic movements and safety at the intersections. The recommendations are, Providing traffic islands as given in the Fig 7.1, will help in orderly movement of vehicles at the intersection. The flow from Perumanallur to the Fly-over during peak hour was . The bus stop is located at the intersection leg of Perumanallur to Fly-over roads. As per IRC 70:1977, the bus stops must be located minimum 75m away from the intersection area. So this bus stop must be shifted to near by convenient place to ensure free flow of vehicles. The rotary intersection can efficiently function up to the capacity of 5000 PCU/hour during the peak hour. Since the peak hour flow for this intersection is 7794 PCU/hour, a traffic signal along with rotary was planned. But the signal cannot be designed since the flow is saturated in Fly-over and Perumanallur. Considering the rapid growth of traffic and to avoid right turn conflicts, a Fly-over is the best option to control the movement of vehicles to minimize delay and improve the level of service of the intersection. B. Conclusion The rapid growth of vehicles has become a major detrimental to road safety. This leads to more congestion at the intersections and increase the risk of accidents. Many intersection in urban areas has become accidents prone and the delay at such intersections was quite high. In order to reduce the risk of accidents and enhance the orderly movement of vehicles, it is very much essential to design the intersections. In this project, an intersection in Tirupur city, which is heavily crowded with vehicles was redesigned and suitable measures are suggested.

References

[1] Tariq Azizr, Er. Neeraj kumar TRAFFIC SIGNAL DESIGN International Research Journal of Engineering and Technology. Volume:08 Issue:03 Mar2021. [2] Wei-Hsun Lee and Chi-Yi Chiu Design and Implementation of a Smart Traffic Signal Control System for Smart City Applications. 16 January 2020. [3] Madhan kumar V, Renuka Prasad M SIGNAL RE-DESIGN Through IRC and WEBSTERS Technology International Research Journal of Science, [4] Engineering and Technology. ISSN: 2395-4752, 2020. [5] Raghavendra S. Sanganaikar et al., Design of Traffic Signal at Kundahallli Junction Bengaluru Karnataka. International Journal of Scientific & Engineering Research, volume 9, Issue 6, June-2018. [6] Vikram Kumar & Neeraj kumar Study of Design Traffic Signal International Research Journal of Engineering and Technology, Volume 5, Issue 12, Dec-2018. [7] Ishant Sharma & Dr. Pradeep K. Gupta Study of Automatic Traffic Signal System of Chandigarh ISSN: 2277-9655, July 2015. [8] P. Saranya & Malliga Senthil Density Based Adaptive Traffic Signal System January 2015. [9] Lutfun Nahar Nipa, Md. Mohibul Islam Intelligent Traffic control System Based on Round Robin Scheduling Algorithm International Journal of Scientific and Research Publication, Volume 5, Issue 8, ISSN 2250-3153, August 2015. [10] K. Vidhya, A. Bazila Banu Design Based Traffic Signal System International Journal of Innovative Research in Science, Engineering and Technology. Volume 3, Special Issue 3, March 2014. [11] Tang-Hsien Chang, Jen-Ting Lin Optimal Signal Timing for oversaturated Intersection Transportation Research Part- B Methodological 34 (6): 471- 491, August 2000. [12] Highway Engineering: S.K.Khanna and C.E.G.Justo. [13] Traffic Engineering and Transport planning: Dr. L.R.Kadiyali [14] IRC 64:1990: Guidelines for capacity of road in rural areas. [15] IRC 65:1976: Recommended practice for traffic rotaries, published by Indian Road Congress at New Delhi.

Copyright

Copyright © 2023 C. Sivasanthosh. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.