a path for horizing your innovative work … - civil 128.pdf · unsignalized intersection safety...

Research Article Impact Factor: 0.621 ISSN: 2319-507X Yogesh Kherde, IJPRET, 2014; Volume 2 (9): 118-126 IJPRET

Available Online at www.ijpret.com

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INTERNATIONAL JOURNAL OF PURE AND APPLIED RESEARCH IN ENGINEERING AND

TECHNOLOGY A PATH FOR HORIZING YOUR INNOVATIVE WORK

STRATEGIES FOR ACCIDENT CONTROL AT UNSIGNALIZED INTERSECTIONS

YOGESH P. KHERDE1, VAIBHAV S. UMAP2

1. ME (Transportation Engineering and Management), IBSS COE, Amravati. 2. Faculty of Civil Engineering of Department ,IBSS COE, Amravati

Accepted Date: 27/02/2014 ; Published Date: 01/05/2014

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Abstract: Highway traffic safety is an important area in transportation engineering. Majority of intersections in the India are unsignalized. The total number of crashes at unsignalized intersections is higher than the number of crashes at signalized intersections. Due to the conflicts from all users, more traffic crashes could happen at unsignalized intersection as compared with roadway segments. This paper introduces an approach to improve unsignalized intersection safety performance, using few strategies for accident reduction at unsignalized intersections, which are based upon application of traffic calming, road markings, warning systems, enhanced signing & road beacons by considering existing geometric design, sight distance, pavement surface conditions, traffic control devices, lighting, which has been already proved to be effective in certain circumstances. Keywords: Strategies, Accident Control, Unsignalized Intersections

Corresponding Author: MR. YOGESH P. KHERDE.

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Yogesh Kherde, IJPRET, 2014; Volume 2 (9): 118-126

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INTRODUCTION

Unsignalized intersections are the most common intersection type. Although their capacities may be lower than intersection types, they do play an important part in the control of traffic in a network. A poorly operating unsignalized intersection may affect a signalized network or the operation of an Intelligent Transportation System.

This paper addresses objectives for reducing collisions in unsignalized intersections, either by improving the intersections and their approaches, or addressing driver compliance.[1]

Causes of Accident at Unsignalized Intersection

This may be attributed to the layout of an intersection, a location where at least two roadways cross each other and multiple vehicles are turning left, right, crossing-over, ect... ongoing activities that may lend themselves to an increased risk of motor vehicle accidents. However, a recent study by the U.S. Department of Transportation, National Highway Traffic Safety Administration (NHTSA) has revealed additional factors that contribute to a greater chance of intersection-related collisions.[8]

The common factors examined were the gender and age of the drivers, weather-related conditions, stoplights or stop signs and pre-crash events that made the collision unavoidable, such as a car crossing into another lane or hazardous road conditions.

Intersection Collisions Often Caused by Drivers

Based on study findings, 46 percent of the traffic accidents in the U.S. were attributed to intersection collisions. Of those accidents, 96 percent were deemed to be caused by the drivers. Some reasons for intersection-related accidents, caused by drivers include, [4]:

Over Speeding

Traffic violations

Poor visibility

Sight distance

Distractions

Incorrectly anticipating the other driver's actions or speed



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1.0 Strategies For Accident Control At Unsignalized Intersections

Traffic calming- Slowing down or reducing traffic.

ITS warning systems- Detect violators & Warn the drivers.

Road markings-Psychological & perceptual clues to lowering speed.

Enhanced Signing & road Beacons -To alert driver & give instructions to users

1.1 Traffic calming

The goals of traffic calming are typically to reduce vehicle speeds, traffic volume, or both. Volume control measures limit traffic by restricting vehicle access. They include full street closures, half closures, diagonal diverters, median barriers, and forced-turn islands. Speed control measures can be divided into three types: vertical, horizontal, and narrowing. Vertical speed controls include speed humps, which are parabolic, circular, or sinusoidal mounds placed across a roadway. Speed tables are basically flat-topped speed humps. Horizontal speed controls slow traffic by requiring vehicles to shift direction in order to maneuver around them. Narrowing roadways controls speed by reducing the amount of lateral space in which vehicles can maneuver,[5].

1.1.1 Chicanes

These involve building out the kerb, usually on alternate sides of the road, to effectively introduce bends into an otherwise straight section of carriageway. This technique can allow two vehicles to pass or permit single vehicle flow only. With the latter, signing can give priority to one direction of flow or alternatively no signed priority relies on inducing driver caution to achieve speed reduction. An important design element is ensuring that the severity of the bend(s) through the chicane allows the safe passage of all non-prohibited vehicles. The speed



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reduction effect of a chicane that allows passage for the largest vehicles is likely to be greatly reduced for cars. At some locations chicanes prevents cyclists from coming into conflict with motor vehicles in the chicanes, [5].

1.1.2 Entry Treatments

This technique generally involves narrowing the entrance to a minor road at a priority junction and incorporating a ramp that raises the highway to the level of the footway. The speeds of turning vehicles are reduced, drivers are made aware of a change in the character of the road and the safety of pedestrians crossing the mouth of the junction is improved,[5].

1.1.3 Roundabouts

A roundabout is a type of circular intersection or junction in which road traffic is slowed and flows almost continuously in one direction around a central island to several exits onto the various intersecting roads.

Roundabouts are safer than both traffic circles and junctions—having 40% fewer vehicle collisions, 80% fewer injuries and 90% fewer serious injuries and fatalities (according to a study



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of a sampling of roundabouts in the United States, when compared with the junctions they replaced). Roundabouts also reduce points of conflict between pedestrians and motor vehicles and are therefore considered to be safer for them, additionally, most feature a safety island refuge where pedestrians may pause mid-crossing. Large roundabouts, especially ones with faster traffic, are unpopular with some cyclists,[2].

1.2 ITS warning systems & Real-Time System

Transportation agencies have used a variety of safety countermeasures, including intersection lighting, enhanced signing and geometric improvements to address these crashes. Recently, though, agencies have turned to Intelligent Transportation Systems as another tool for improving safety particularly those where poor sight distance and gap acceptance are a problem. Intersection conflict warning systems address crashes at stop-controlled intersections by providing drivers – on both the major and minor roads – with a dynamic warning of other vehicles approaching the intersection.

The Intersection Warning System project is used the Traffic Conflict Technique to discover that traffic conflicts (sudden braking, sudden acceleration or swerving) at intersections could be reduced by 54 percent.

ITS deployments and research is also extensively going in following areas :

1 )Intersection Warning System

2)Stop Sign Warning System

3)Curve Warning System

4)Arterial Travel Time Monitoring System Using Bluetooth Technology



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5)Cooperative Intersection Collision Avoidance System (CICAS)

6)Smartphone Based Novice Teenage Driver Support System, [3].

1.3 Road markings

The essential purpose of road markings is to guide and control traffic on a highway. They supplement the function of traffic signs. The markings serve as a psychological barrier and signify the delineation of traffic path and its lateral clearance from traffic hazards for the safe movement of traffic. Hence they are very important to ensure the safe, smooth and harmonious flow of traffic. Various types of road markings like longitudinal markings, transverse markings, object markings and special markings to warn the driver about the hazardous locations in the road are very important for increasing safety.

Road markings are aids to control traffic by exercising psychological control over the road users. They are made use of in delineating the carriage way as well as marking obstructions, to ensure safe driving. They also assist safe pedestrian crossing. Transverse markings are provided along the width of the road. Road markings also contain word messages, but since it is time consuming to understand compared to other markings there are only very few of them.



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Markings are also used to warn the driver about the hazardous locations ahead. Thus road markings ensure smooth flow of traffic providing safety also to the road users, [7].

1.4 Enhanced Signing & Beacons



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One-third of all intersection crashes in the India, and more than 40 percent of fatal crashes, occur at stop sign-controlled intersections. A major problem is failure to see the stop sign and/or to know where to stop. Past research has shown that simple, low-cost treatment enhancements such as increasing the visibility of stop signs, and/or adding pavement markings, can improve driver compliance with the stop sign and reduce the number and severity of crashes.

Overhead signs are preferred to post-mounted signs because the overhead signs can be placed directly over the lanes & give clear visibility. This driving task is done at intersections where you must come to a stop. It begins at the point where you can see the intersection and ends just before you enter the intersection.

Flashing beacons may be particularly beneficial for unsignalized intersections where angle collisions due to lack of driver awareness of intersections are more common.(2) Flashing beacons can be designed in such a way that they flash all the time or only when a sensor detects a vehicle approaching the intersection (an actuated beacon). Beacons can be installed either overhead, as shown in figure , or mounted directly onto a STOP sign, [7].

2.0 Conclusion

Unsignalized intersections pose a special problem for potential collisions because of the priority of traffic flow on the main road, particularly in rural and suburban areas. This guide addresses objectives for reducing collisions in unsignalized intersections, either by improving the intersections and their approaches, or addressing driver compliance.

Although this project has not 100% safety aspects for unsignalized intersection, it demonstrates a comprehensive approach to identifying the root issue associated with a crash problem and then developing an appropriate countermeasure.

The intent research is to identify innovative methods of improving safety intersection locations, particularly on high-speed, multi-lane roadways.

3.0 References

1. A Policy on Geometric Design of Highways and Streets, 4th Edition. AASHTO, Washington, D.C., 2001.

2. http://www.fhwa.dot.gov/publications/research/safety/08048/



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3. http://www.itsmn.org/index.php/news/75-its-minnesota-at-the-national-association-for-county- engineers-nace-conference

4. http://www.egletwall.com/Resources/Articles/Intersection-Related-Accidents-Caused-by- Driver-Actions-Study-Says.shtml

5. http://safety.fhwa.dot.gov/intersection/unsignalized/presentations/nchrp500_v5/

6. Hameed Aswad Mohammed, Study Of Traffic Safety Evaluation And Improvements At Unsignalized Intersections, Al-Qadisiya Journal For Engineering Sciences, Vol. 5, No. 2, 150-165, Year 2012.

7. Christian, T. R., Barnak, J. J., and Karoly, A. E. 1981. Evaluation of Limited Sight Distance Warning Signs, New York State Department of Transportation, Albany.

8. Federal Highway Administration, Motor Vehicle Accident Costs. 1994. Technical Advisory T-7570.2, U.S. Deptt. of Transportation, Washington,DC.

9. Glennon, J. C., Glauz, W. D., Sharp, M. C., and Thorson, B. A. 1977. "Critique of the Traffic Conflict Technique" Transportation Research Record 576. Transportation Research Board, National Research Council, Washington, DC. pp. 3

a path for horizing your innovative work … - civil 128.pdf · unsignalized intersection safety...

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