İstanbul'da ışıklı yaya geçitlerinde sürücülerin yatay işaretlemeye uymama oranlarının trafik ışığı konumuyla ilişkisinin incelenmesi
Investigation of the relationship between the violation  rates of road marking and the positions of the traffic light on the signalized pedestrian crossings in Istanbul
Yazar: ZELİHA ÇAĞLA ÇAĞLAR
Danışman: DOÇ. DR. KEMAL SELÇUK ÖĞÜT
İstanbul Teknik Üniversitesi / Fen Bilimleri Enstitüsü / İnşaat Mühendisliği Ana Bilim Dalı / Ulaştırma Mühendisliği Bilim Dalı
Derece: Yüksek Lisans, 2017
Konu: Mühendislik Bilimleri = Engineering Sciences ; Trafik = Traffic ; Ulaşım = Transportation
Dizin: Şehiriçi trafiği = Urban traffic

Özet:
Karayollarında yolculuk, birçok unsuru içinde barındıran bir olgudur. Güvenli bir yolculuk için hem yol kullanıcılarına, hem yolu inşa eden kurumlara büyük sorumluluklar düşmektedir. Dünyada yapılan birçok çalışmada trafik kazalarının azaltılmasında kullanıcı hatalarının önüne geçmenin tek başına yeterli olmadığı, yol tasarımının da en az insan unsuru kadar önemli olduğu ortaya çıktığından, kazaların önüne geçmek, kazalardan doğacak kötü sonuçları azaltmak için yol tasarımına ve işaretlemelere özen gösterilmelidir. Trafik kurallarına uyulmamasını azaltmak için ülkemizde, dünyanın birçok ülkesinde olduğu gibi çeşitli uygulamalar yapılmaktadır. 
Bu tez çalışmasında, ışıklı yaya geçitlerinde dur çizgisine ve yaya geçidine uyulmasını arttırmak için yapılacaklar üzerinde durulmuş, yatay ve düşey işaretlemelerin nerede olması gerektiğine dair öngörülerde bulunmak amaçlanmıştır. Çalışmada kullanılan veriler, İstanbul Büyükşehir Belediyesi (İBB) trafik kameraları yardımıyla İstanbul'un çeşitli semtlerinde 26 yaya geçidinden toplanmış ayrıca her bir yaya geçidine gidilerek yatay işaretlemelerin konumları ve trafik ışığının yüksekliği ölçülmüştür.
Saha çalışması sırasında, dur çizgisine uymama her yaya geçidinde gözlemlenmiş olup, bu kurala uymama oranı yaya geçidi özelliklerine göre değişmektedir. Tüm ışıklardaki sağ, sol ve orta şeritlere birlikte bakıldığında kurala uymama konusunda farklılık olduğu, öte yandan aynı kavşaktaki sağ, sol ve orta şeritlere bakıldığında kendi içlerinde büyük farklılıklar olmadığı belirlenmiştir. 
En fazla dur çizgisine uymama (%60), 1295 numaralı yaya geçidinde, en az kurala uymama (%7) ise, 3637 numaralı yaya geçidinde yapılmıştır. 
Yaya geçidi çizgisine uymama, incelenen kavşakların %85'inde gözlenmiştir. En fazla yaya geçidi çizgisine uymama (%23), 1295 numaralı kavşakta yapılmıştır. 
Yapılan çalışma sonucunda, ışıklarda yatay ve düşey işaretlemelerin yer ve özelliklerinin dur ve yaya çizgisine uyulmama oranını etkilediği anlaşılmıştır. Trafik ışığı ile dur çizgisi arasındaki uzaklığın artması ve kırmızı bant bulunması dur çizgisine ve yaya geçidine uyulmamasını arttırmaktadır. Buna karşılık, trafik ışığının konsol tipi olması ve ışık levha boyunun fazla olması dur çizgisi ve yaya geçidi çizgisine uyulmamasını azaltmaktadır. Trafik güvenliği açısından dur ve yaya geçidi çizgisine uymamanın azaltılması için ışıklardaki yatay ve düşey işaretlemelerin ölçülerine özen gösterilmelidir.

Abstract:
Transportation is a complex concept, and transportation safety includes several factors, from which both road users and road designers are responsible. As shown in many studies, to reduce the traffic accidents, traffic signs and markings are as important as the driver behaviour. To avoid accidents and their consequences, roads must be designed and proper marking should be applied. There are various techniques to increase the obedience to the traffic rules.
The aim of this study is the investigation of the relationship between the violation rates of marking and the positions of the traffic light at signalized pedestrian crossings in Istanbul. The dataset is obtained from the traffic cameras of Metropolitan Municipality of Istanbul. In the scope of this study, 30-cycle sampled datasets from 26 different intersection approaches in Istanbul are used. 15 among these approaches have three lanes and 11 have two lanes. During the observations, the points at which the vehicles stopped at the red light were identified. 
Pedestrian crossings occur wherever the pedestrian network intersects the roadway network. Pedestrians are extremely vulnerable at these locations because of their relatively slow speeds compared to vehicles. For these reason, pedestrian safety should have the highest priority when designing crossings. Since the pedestrians are actually in the roadway at intersections and crossings, many of the recommendations below involve roadway design specifically, including markings, signs, signalization, and geometry. 
Stop bars are typically placed at intersections (where motorists are required to stop) to prevent overhang into crosswalk areas. The intersection design requires consideration of all potential users, especially pedestrians who are the most vulnerable while crossing. Design solutions need to protect the safety of pedestrians, while similarly improving their accessibility and mobility. At the same time, design solutions still need to meet the needs of motorists and bicyclists. 
Carefully implemented engineering studies can help to determine the best solutions for each location on a case-by-case basis. Sometimes what is the best design solution for pedestrians does not work well for bicycles and/or vehicles. In this context, visibility might be key safety issue on the pedestrian crossings. It is important that drivers approaching a crossing have good visibility of the area and any pedestrians about to cross. Similarly, the pedestrians must be able to see approaching vehicles, as well.
The controlled crossings manage the interaction between pedestrians and vehicles, and present operational benefits to pedestrians by providing priority over vehicles either at all times or for allocated periods of time. This priority can provide a sense of security for pedestrians, encourage pedestrians to cross at the controlled location and limit the number of locations where pedestrian crossings occur.
Pedestrian crosswalk markings define and delineate the path for pedestrians to cross the roadway and serve to reduce the potential for conflicts with motor vehicles. Furthermore, marked crosswalks alert motorists to the potential of pedestrians crossing and define the area where pedestrians have the right-of-way. The crosswalks at signalized crossings are generally marked with solid white parallel retro-reflective lines 10 cm to 20 cm wide, extending across the entire width of pavement. The width of the crosswalk between the lines is usually determined by the widths of the connected sidewalks and the expected two-way pedestrian flows utilizing the crossing at the peak time. The crosswalk must be at least 2.5 m wide while widths of 3 m to 4 m are typical of urban areas with significant pedestrian activity. In general, the design of pedestrian crosswalk is based on the following principles: crosswalks should line up with proposed sidewalks or dropped curbs, crosswalks should not cross over the centre median where the median is not equipped with wheelchair ramps or at-grade depressions, pedestrian signal heads should be positioned within the extension of the crosswalk if possible, there should be separate crossings for each direction at a corner, the kerb crossings should be in the direct line of the pedestrian through route. Where this is not possible, environmental or tactile cues should guide people to the crossing point, the kerb should be perpendicular to the pedestrian through route, drivers (particularly those turning left) should be able to predict the location of pedestrians who are about to leave the kerb, vehicle turning speeds should be slow.
All pedestrian facilities must be planned, designed, and built in accordance with existing standards as applicable. In some situations, the current standard may not be achievable due to the geometric, environmental, or other constraints. In these situations, variances from the standard may be acceptable. However, a facility should not typically be built to less than the minimum standards described.
According to the results of the study, the violations of stop line have been observed at each approach, however the type and amount of the violation changes with the features of crossings. Right, left and middle lanes have different violation rates; however, no major difference between lanes of an approach is identified in term of violation. The biggest violation of stop line rate is 60% observed on the light number 1295. The smallest violation of stop line rate is 7% observed on the light number 3637.
The violation of pedestrian crossing line is observed 85% of all approaches. The most violation of crossing line rate is 23% at the light number 1295. There is no violation of crossing line at eight of the crossings observed.
The pavement marking and traffic light design is critical for the violation rate. If the distance between traffic light and stop line increases and there is a red pavement marking, the number of the violations of the stop line and the crossing line increases. If the type of traffic light is console and the height of traffic light is fairly high, the violation of stop line and crossing line similarly increases. For these reasons, the sign and pavement markings should have high priority when designing or retrofitting the intersections and crossings.
In the study conducted, it was found that the location and characteristics of pavement markings and traffic light in signalized intersections affected the violations to the stop and to the pedestrian crossing lines, which is examined by regression analysis. In the model of stop line violation; the dependent variable is the violation of stop line rate, the independent variables which are investigated in multiple regression analysis are EF (average distance between traffic lights and stop line), K (the type of traffic light (whether console type)), B (whether the red pavement marking) and Y (the height of traffic light). On the other hand, in the model of crossing line violation; the dependent variable is the violation of crossing line rate, the independent variables which are investigated in multiple regression analysis are TY (average distance between traffic lights and crossing line), K (the type of traffic light (whether console type)), B (whether the red pavement marking) and Y (the height of traffic light).
According to the results of the study, the short distance between the stop line and the traffic light in the signalized pedestrian crossings provides the reduction of the violation of stop line. Likewise, the short distance between the traffic light and the pedestrian crossing line provides a reduction of the violation of pedestrian crossings. 
As a result of this study, although the distance of traffic light can not be precisely located, obviously it is appropriate to place it at the starting point of the starting point of the pedestrian crossing and indirectly pedestrian crossing since it is close to the stop line.
One of the weakness of this study is the number of observations. Only 26 pedestrian crossings (30 cycles at each crossing) were observed. Increasing the number of observations might be provide more realistic for this effect. Moreover, if the observations made in different weather conditions can be obtained, different results regarding the violation of stop line and the violation of pedestrian crossings can be examined.
For future studies pre-post studies at signalized intersections to investigate the effects of the electronic control system on the violations is recommended.