Safety effects of paved shoulders on intercity highways in India

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SAFETY EFFECTS OF PAVED SHOULDERS ON INTERCITY HIGHWAYS IN INDIA

LAXMAN SINGH BISHT

DEPARTMENT OF CIVIL ENGINEERING INDIAN INSTITUTE OF TECHNOLOGY DELHI

NEW DELHI, INDIA

OCTOBER 2022

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SAFETY EFFECTS OF PAVED SHOULDERS ON INTERCITY HIGHWAYS IN INDIA

by

LAXMAN SINGH BISHT

Department of Civil Engineering

A thesis submitted in fulfilment of the requirement for the degree of Doctor of Philosophy

to the

INDIAN INSTITUTE OF TECHNOLOGY DELHI, INDIA OCTOBER 2022

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Dedications

To my late grandmother To my parents

To Professor Geetam Tiwari

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Certificate

This is to certify that the thesis entitled “Safety Effects of Paved Shoulders on Intercity Highways in India” is being submitted by Mr Laxman Singh Bisht to the Indian Institute of Technology Delhi, India, for the award of the degree of Doctor of Philosophy, is a record of original bona fide research work carried out by him. Laxman has worked under my guidance and supervision.

To the best of my knowledge, the thesis has reached the requisite standard. The material contained in this thesis has not been submitted, in part or in full, to any other university or institute for the award of any degree or diploma.

Dated: October 2022

(Dr. Geetam Tiwari) Professor and Head Transportation Research and Injury Prevention Centre (TRIP-C)

Indian Institute of Technology Delhi New Delhi -110016, India

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Acknowledgements

गुरुर्ब्रह्माग्रुरुर्वरष्ुुःगुरुर्देवोमहेश्वरुः।गुरुुः साक्षात ्परंर्ब्ह्मतस्मैश्री गुरवेनमुः॥ (Our creation is that guru; the duration of our lives is that guru; our trials, tribulations, illnesses, calamities, and the death of the body is that guru. There is a guru nearby and a guru that is beyond the beyond. I make my offering to the beautiful remover of my darkness, my ignorance; it is to you I bow and lay down my life.)

I take this opportunity to express my sincere gratitude to my mentor and supervisor, Prof. Geetam Tiwari, for her invaluable guidance, support, motivation, and constant encouragement. Her continuous guidance and support have helped me understand the research work's concepts and methodology. There are no words to express my gratitude for allowing me to work on various projects during my PhD tenure. I also like to thank all my SRC members, Dr Suresh Bhalla (Chairman), Prof. K. R. Rao (internal expert), and Prof.

Niladri Chatterjee (external expert), for their invaluable suggestions and support during various stages of my research study.

I want to thank Late Prof. Dinesh Mohan for offering valuable discussions during projects at TRIP-Centre and always encouraging me to look for scientific evidence in road safety. His way of thinking will always motivate me to go deep into any research problem that I would possibly take in the future. Initial discussions with Prof. Kavi Bhalla have helped me understand the epidemiology application in road safety. I was fortunate to work with Prof.

K.N. Jha on various projects in TRIP-C. I want to thank him for his friendly behaviour whenever we met. Prof. K.R. Rao's comments and questions helped to understand the statistical issues in depth.

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I gratefully acknowledge the funding received for my PhD from the Ministry of Urban Development (MoUD) awards for 2018 to 2019 and 2019 to 2020. I gratefully acknowledge the VREF TRIPP fellowship for the year 2020 to 2021. These awards helped me to carry out data collection for my PhD work. I would also like to acknowledge the VREF fellowship awarded for 2017-2018. I am thankful to the Department of Civil engineering for providing me with a contingency fund to attend a conference.

I am grateful to Dr Navdeep Asija for providing FIR data on Punjab highways. Dr Sumeet Gupta for initial telephonic discussions on data-related issues. I also thank Mr Meku (M.Tech. scholar), Mr Praveen Ghanghas (PhD scholar) and my brother Mr Deepak Bisht for providing immense support during data collection. I am thankful to Mr. Akhilesh Srivastav for helping to get traffic volume data. I also convey special thanks to Mr Mahesh Guar and Ms Hema Narang for their tremendous administrative support. Mr Hari Chand for his friendly and positive talks during his visit to my lab. I would also like to thank the staff of the civil engineering department for being supportive and friendly during my short visits. Also, thank the staff of the HoD civil engineering department for always being cooperative.

I am thankful to my friends and colleagues of the transportation family Chetan Doddamani, Mohit Singh, Richa Ahuja, Deotima, Shayesta, Punyabit, Pranav and Saurav. Our evening teas and dining out had always been interesting in various non-technical developments in our lab, on campus and globally. Discussion with Pankaj Rawat on various issues of modelling and software were very fruitful and helpful. I am thankful to him for helping me. I also like to thank all the juniors of the TRIPP lab of MS 804 and Ms 811. I am incredibly grateful to all under-graduates’ students who supported me in the tedious and laborious data entry work.

I luckily met Mr. (Dr.) GSK, whose company I always enjoyed, and his ideas were unique and wondrous. We really enjoyed our various trips, and especially Wednesday evening tea at Amul and Nescafe. I thank you for all our planned and unplanned trips during our stay

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at IIT Delhi. Thanks for gifting me your antique bicycle. I want to thank my friends Dr.

Madhumita and Dr. Abhinav for all the technical discussions and other support. I also thank Tulja Bhawani and Ashutosh Pandey for late-night adda, cycling and walk trips in Delhi.

I am indebted to IIT Delhi SPIC MACAY friends who were family away from family on campus. SPIC MACAY IIT Delhi experience has groomed my personality significantly. I thank IIT Delhi NSS friends for providing me a platform for that I love to do in my life. I want to acknowledge the sports facility of IIT Delhi for providing me with a space for health and fitness.

Unconditional and unmatched love from a few dogs of IIT Delhi has helped me relieve stress and maintain my mental health during the PhD journey. I convey my eternal love to

"Mottu" for all hugs and licks when I used to return to the hostel from late-night from the lab.

His hugs were always therapeutic to me. I cherished my time with the dogs of IIT Delhi and elsewhere in my recreational trips.

I want to express my gratitude to my parents for everything. I have reached here today because of your relentless effort, sacrifices and faith in me. I wholeheartedly thank my parents today for their blessings and the constant support they have always been for me. There are not enough words to express my gratitude to them for everything they have done for me. I would also like to thank my younger brother for always supporting me, especially in the data collection. I wish you a bright and prosperous future.

Today I am using this opportunity to remember my late grandmother for being with me spiritually all time. Daadi Ji, you may have passed on, but your memories will always live on within me.

At the end of my PhD life, I started a new life and all thanks to Ms Gauri Arora for believing in me. During the early day of our relationship, you motivated me in research writing and consistent work when I needed it most. Especial thanks to tea of Amul for helping us to break the ice.

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On this journey, there were many gloomy days and unquiet nights. However, you must remember that "your life is your life; know it while you have it." Charles Bukowski rightly said that don’t let your life be clubbed into dank submission. Be on the watch, there are ways out. There is a light somewhere. It may not be much light, but it beats the darkness. Be on the watch, and the gods will offer you chances. You can’t beat death, but you can beat death in life sometimes. And the more often you learn to do it, the more light there will be. You are marvellous, and the gods wait to delight in you. With this, I want to thank almighty for helping me through hard times and for giving me the strength to keep going.

Laxman Singh Bisht October 2022

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Abstract

This thesis aimed to estimate the effect of paved shoulder width on the number of fatal crashes on intercity highways and to determine the risk factors of fatal crashes on an expressway in India. The objectives of this thesis are as follows (i) to identify road traffic crash (RTC) patterns on the selected intercity highways and expressway stretches of India; (ii) to assess the effect of paved shoulder width on fatal RTCs on the selected intercity highway; (iii) to assess the impact of the paved shoulder width on the selected intercity highway segments having multiple fatal crashes; and (iv) to estimate the role of crash contributory factors in the presence of constant paved shoulder width on segments of an intercity expressway.

Therefore, first, this study analyzed the fatal crash characteristics on the selected intercity highways and an expressway. Subsequently, the effect of paved shoulder width and other crash contributory risk factors were identified on the selected intercity highway segments using the case-control (C-C) method. The C-C method is an observational epidemiological approach used to examine the possible relation of a risk factor to a specific outcome. Whereas, in the case of an expressway with constant paved shoulder width, the crash contributory risk factors were determined with the help of negative binomial random parameter (RPNB) approaches.

The selected intercity highways are part of the national highway (NH), i.e., NH 7 and NH 44, and are open access highways with varying paved shoulder widths. And the Yamuna Expressway (YE) is access-controlled in Uttar Pradesh. In this study, primary data were

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collected with the help of surveys, as no central database exists in India. We carried out field surveys on NH 7, and NH 44 as traffic volume, speed, and cross-sectional geometrics data were unavailable during this study's initial data collection stage. Whereas in the case of YE, crash, speed, traffic volume, and geometric data were collected as secondary data. This study employed fatal crashes, traffic volume, operational speed, and geometric and roadside data to develop statistical models.

The crash characteristics revealed that rear-end crashes have a substantial share in total fatal crashes. Vulnerable road users have a high relative risk on the studied highway and expressway stretch. In NH 44, pedestrian fatalities are high. Cars, trucks, and buses are primarily involved as impacting vehicles in fatal crashes. Nighttime crashes have a slightly higher proportion compared to daytime crashes. Next, for NH 7, the estimated odds ratio (OR) shows that paved shoulder widths up to 2.0 m are safe for all users. This finding is consistent for both highway stretches, i.e., NH 7 and NH 44.

In contrast, paved shoulder width of more than 2.0 m has varying effects based on the fatal crash type. The varying impact could be attributed to the roadside context of the highway and prevailing operational speeds. Subsequently, this study explored the C-C method for the applicability of considering multiple crash segments on the selected intercity 6L highways (NH 44). The safety effectiveness of paved shoulder width assessment shows that paved shoulder width of more than 2.0 m is a risk factor for multiple fatal crash segments compared to a paved shoulder width of 1.0 to 1.5 m. In addition, results show that shoulder width between 1.5 to 2.0 m reduces the risk of multiple fatal crashes. Ordinal logistic regression results show that the segments with wider shoulders have less risk of multiple crashes than the narrow shoulder.

However, additional studies need to be conducted based on the collision types and locations where multiple fatal crashes have occurred.

In the case of the YE stretch, parsimonious model results revealed that AADT and vertical curve length are significant risk factors for rear-end crashes. AADT and vertical curve

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length are the significant random parameters to capture the segment-specific unobserved heterogeneity. The findings indicate that the expressway design should be calibrated as per the local traffic mix and prevailing operational speed characteristics. Further, the results indicate providing bus lay-by and truck drivers' rest areas at regular intervals on the expressway. In addition, the location of the pedestrian underpasses should be determined based on the presence of villages in the vicinity of the expressway.

To sum up, this study was a unique attempt to assess the safety effectiveness of the paved shoulders in case of heterogeneous traffic on divided 4L and 6L highways in India. The study demonstrated that the matched case-control methodology could be an alternative method in the limited data availability scenario to assess the safety effects of the interventions.

The outcomes of this study would help the road-owning agencies in India to consider paved shoulders as one of the road safety interventions to improve safety. Especially the provision of the paved shoulder can enhance the safety of vulnerable road users (VRUs), especially motorized-two wheelers (MTW) users. It can also reduce the risk of multiple fatal crashes on multilane highways. However, the results presented in this study are data specific.

In the future, additional studies on various intercity highways using detailed databases would help provide conclusive evidence of the safety effectiveness of paved shoulder width.

Besides, this study makes a strong case for developing a rich and centralized database for road safety risk factors in India. Such databases would help researchers to conduct advanced research, eventually promoting research-based findings and safety interventions to reduce crashes and their societal burden. Along similar lines, it is also recommended that a dedicated crash data recording system should be developed within each state's police department.

Moreover, the hospital and police databases should be linked and updated on time to deal with the underreporting of crashes.

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सार

इस थीससस का उद्देश्य इंटरससटी राजमार्गों पर घातक दुघघटनाओं की संख्या पर पक्की शोल्डर की चौडाई के प्रभाव का अनुमान लर्गानाऔरभारतमेंएकएक्सप्रेसवेपरघातक दुघघटनाओंकेजोसिमकारकोंकासनर्ाघरणकरनाथा।इसथीससस

के उद्देश्य इस प्रकार हैं (i) भारत के चयसनत इंटरससटी राजमार्गों और एक्सप्रेसवे सहस्सों पर सडक यातायात दुघघटना (आरटीसी)

पैटनघ की पहचान करना; (ii) चयसनत इंटरससटी राजमार्गघ पर घातक आरटीसी पर पक्की शोल्डर की चौडाई के प्रभाव का

आकलन करना; (iii) कई घातक दुघघटनाओं वाले चयसनत इंटरससटी राजमार्गघ िंडों पर पक्की शोल्डर की चौडाई के प्रभाव का

आकलन करना; और (iv) इंटरससटी एक्सप्रेसवे के िंडों पर सनरंतर पक्की शोल्डर की चौडाई की उपसस्थसत में दुघघटना योर्गदान कारकों की भूसमका का अनुमान लर्गाने के सलए।

इससलए, सबसे पहले, इस अध्ययन ने चयसनत इंटरससटी राजमार्गों और एक एक्सप्रेसवे पर घातक दुघघटना सवशेषताओं

कासवश्लेषणसकया।इसकेबाद, केस-कंट्रोल (C-C) पद्धसतकाउपयोर्गकरकेचयसनत इंटरससटी हाईवेसेर्गमेंटपरपक्कीशोल्डर की चौडाई और अन्य दुघघटना योर्गदान जोसिम कारकों के प्रभाव की पहचान की र्गई। C-C पद्धसत एक अवलोकन संबंर्ी

महामारी सवज्ञान दृसिकोण है सजसका उपयोर्ग सकसी सवसशि पररणाम के सलए जोसिम कारक के संभासवत संबंर् की जांच करने

के सलए सकया जाता है। जबसक, लर्गातार पक्की शोल्डर की चौडाई वाले एक्सप्रेसवे के मामले में, नकारात्मक सिपद यादृसछिक पैरामीटर (RPNB) दृसिकोणों की मदद से दुघघटना अंशदायी जोसिम कारकों का सनर्ाघरण सकया र्गया था।

चयसनत इंटरससटी राजमार्गघ राष्ट्ट्रीय राजमार्गघ (NH), यानी NH 7 और NH 44 का सहस्सा हैं, और अलर्ग-अलर्ग पक्की शोल्डर की चौडाई वाले िुले पह ंच वाले राजमार्गघ हैं। और यमुना एक्सप्रेसवे (YE) उत्तर प्रदेश में एक्सेस-सनयंसित है।

इस अध्ययन में, सवेक्षणों की सहायता से प्राथसमक डेटा एकि सकया र्गया था, क्योंसक भारत में कोई केंद्रीय डेटाबेस मौजूद नहीं

है।हमने NH 7, और NH 44 परक्षेिसवेक्षणसकयाक्योंसकइसअध्ययनके प्रारंसभक डेटा संग्रह चरणकेदौरानट्रैस़िककी

मािा, र्गसतऔरक्रॉस-सेक्शनलज्यासमतीयडेटा अनुपलब्र् थे।जबसक YE केमामलेमें, दुघघटना, र्गसत, यातायातकीमािाऔर

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ज्यासमतीय डेटा को सितीयक डेटा के रूप में एकि सकया र्गया था। इस अध्ययन ने सांसख्यकीय मॉडल सवकससत करने के सलए

घातक दुघघटनाओं, यातायात की मािा, पररचालन र्गसत और ज्यासमतीय और सडक के सकनारे के डेटा को सनयोसजत सकया।

दुघघटना की सवशेषताओं से पता चला सक कुल घातक दुघघटनाओं में ररयर-एंड क्रैश का एक बडा सहस्सा है। कमजोर सडक उपयोर्गकताघ (VRUs) का अध्ययन सकए र्गए राजमार्गघ और एक्सप्रेसवे िंड पर एक उछच सापेक्ष जोसिम है। NH 44 में, पैदल चलने वालों की मौत असर्क होती है। घातक दुघघटनाओं में वाहनों को प्रभासवत करने वाले मुख्य रूप से कार, ट्रक और

बसें शासमल हैं। रात के समय दुघघटनाओं का अनुपात सदन के समय दुघघटनाओं की तुलना में थोडा असर्क होता है। इसके बाद, NH 7 के सलए, अनुमासनत ऑड्स रेसशयो (OR) दशाघता है सक 2.0 मीटर तक पक्की शोल्डर की चौडाई सभी उपयोर्गकताघओं

के सलए सुरसक्षत है। यह िोज दोनों राजमार्गघ िंडों, यानी NH 7 और NH 44 के सलए सुसंर्गत है।

इसके सवपरीत, 2.0 मीटर से असर्क की पक्की शोल्डर की चौडाई घातक दुघघटना प्रकार के आर्ार पर अलर्ग-अलर्ग प्रभावडालतीहै।अलर्ग-अलर्गप्रभावकोराजमार्गघकेसडककेसकनारेके संदभघ औरप्रचसलतपररचालनर्गसतकेसलएसजम्मेदार

ठहरायाजासकताहै।इसकेबाद, इसअध्ययनने चयसनत इंटरससटी 6L राजमार्गों (NH 44) परकईक्रैशसेर्गमेंटपरसवचार करनेकी प्रयोज्यताके सलए CC पद्धसतका पता लर्गाया।पक्कीशोल्डरकी चौडाईकेआकलन की सुरक्षा प्रभावशीलतासे

पता चलता है सक 2.0 मीटर से असर्क की पक्की शोल्डर की चौडाई 1.0 से 1.5 मीटर की पक्की शोल्डर की चौडाई की

तुलना में कई घातक दुघघटना िंडों के सलए एक जोसिम कारक है। इसके अलावा, पररणाम बताते हैं सक 1.5 से 2.0 मीटर के

बीचशोल्डर की चौडाईकईघातक दुघघटनाओं केजोसिमकोकमकरतीहै।ऑसडघनललॉसजसस्टक ररग्रेशनपररणामबतातेहैं

सक चौडे कंर्ों वाले सेर्गमेंट में नैरो शोल्डर की तुलना में मल्टीपल क्रैश का जोसिम कम होता है। हालांसक, टकराव के प्रकारों

और उन स्थानों के आर्ार पर असतररक्त अध्ययन सकए जाने की आवश्यकता है जहां कई घातक दुघघटनाएं ह ई हैं।

YE के मामले में, पारसीमोसनयस मॉडल पररणामों से पता चला सक AADT और ऊध्वाघर्र वक्र लंबाई ररयर-एंड क्रैश के सलए महत्वपूणघ जोसिम कारक हैं। AADT और ऊध्वाघर्र वक्र लंबाई िंड-सवसशि अप्रमासणत सवषमता को पकडने के

सलए महत्वपूणघ यादृसछिक पैरामीटर हैं। सनष्ट्कषों से संकेत समलता है सक एक्सप्रेसवे के सडजाइन को स्थानीय यातायात समश्रण और

प्रचसलत पररचालन र्गसत सवशेषताओं के अनुसार अंशांसकत सकया जाना चासहए। इसके अलावा, पररणाम एक्सप्रेसवे पर सनयसमत अंतराल पर बस ले-बाय और ट्रक ड्राइवरों के सवश्राम क्षेि प्रदान करने का संकेत देते हैं। इसके अलावा, पैदल यािी अंडरपास का

स्थान एक्सप्रेसवे के आसपास के र्गांवों की उपसस्थसत के आर्ार पर सनर्ाघररत सकया जाना चासहए।

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संक्षेप में, यह अध्ययन भारत में सवभासजत 4L और 6L राजमार्गों पर सवषम यातायात के मामले में पक्के कंर्ों की

सुरक्षा प्रभावशीलता का आकलन करने का एक पहला प्रयास था। अध्ययन ने प्रदसशघत सकया सक हस्तक्षेपों के सुरक्षा प्रभावों का

आकलन करने के सलए सीसमत डेटा उपलब्र्ता पररदृश्य में समलान की र्गई C-C पद्धसत एक वैकसल्पक सवसर् हो सकती है। इस अध्ययन के पररणाम भारत में सडक के स्वासमत्व वाली एजेंससयों को सुरक्षा में सुर्ार के सलए सडक सुरक्षा उपायों में से एक के

रूप में पक्के कंर्ों पर सवचार करने में मदद करेंर्गे। सवशेष रूप से पेव्ड शोल्डर का प्रावर्ान VRUs की सुरक्षा को बढा सकता

है, सवशेष रूप से मोटर चासलत दुपसहया वाहन (MTW) उपयोर्गकताघओं की। यह मल्टीलेन हाईवे पर कई घातक दुघघटनाओं के

जोसिमको भी कमकर सकता है।हालााँसक, इस अध्ययन में प्रस्तुत पररणाम डेटासवसशि हैं।भसवष्ट्य में, सवस्तृत डेटाबेस का

उपयोर्ग करते ह ए सवसभन्न इंटरससटी राजमार्गों पर असतररक्त अध्ययन से पक्की शोल्डर की चौडाई की सुरक्षा प्रभावशीलता का

सनणाघयक सबूत प्रदान करने में मदद समलेर्गी। इसके अलावा, यह अध्ययन भारत में सडक सुरक्षा जोसिम कारकों के सलए एक समृद्ध और केंद्रीकृत डेटाबेस सवकससत करने के सलए एक मजबूत मामला बनाता है। इस तरह के डेटाबेस शोर्कताघओं को उन्नत

शोर्करनेमेंमददकरेंर्गे, अंततः दुघघटनाओं औरउनकेसामासजकबोझकोकमकरनेकेसलए अनुसंर्ान-आर्ाररतसनष्ट्कषोंऔर सुरक्षा हस्तक्षेपों को बढावा देंर्गे। इसी तरह की तजघ पर, यह भी ससफाररश की जाती है सक प्रत्येक राज्य के पुसलस सवभार्ग के भीतर एक समसपघत क्रैश डेटा ररकॉसडिंर्ग ससस्टम सवकससत सकया जाना चासहए। इसके अलावा, दुघघटनाओं की कम ररपोसटिंर्ग से सनपटने के

सलए अस्पताल और पुसलस डेटाबेस को समय पर जोडा और अद्यतन सकया जाना चासहए।

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List of Tables

Table 2-1 Summary of the effect of highway geometrics on crashes ... 24

Table 2-2 Summary of the effect of the number of lanes and lane width on crashes ... 28

Table 2-3 Summary of the effect of horizontal and vertical alignment on crashes ... 32

Table 2-4 Summary of the effect of roadside elements on crashes ... 34

Table 2-5 Summary of the effect of the shoulder width on crashes ... 39

Table 3-1 Code used for the variables during the preliminary study ... 59

Table 3-2 Typical examples of a coded sheet for intercity highway (NH 9) from Rudrapur to Banbassa, Uttarakhand ... 60

Table 3-3 Summary of the surveyed intercity highway stretches ... 61

Table 3-4 Summary of the preliminary study highway stretches in Punjab ... 65

Table 3-5 Summary of the final selected highway and expressway stretches ... 67

Table 3-6 The summary of the primary data collection methods ... 71

Table 3-7 Summary of the secondary data sources ... 78

Table 3-8 Summary of the crash data variables of YE ... 80

Table 3-9 Summary of data type and sources used in this study ... 81

Table 4-1 Summary of the YE segments based on the characteristic of geometric variables 90 Table 5-1 Typical unmatched C-C study design setup... 119

Table 5-2 Matched case-control setup with concordant and discordant pairs ... 120

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Table 5-3 Summary of the variables for the unmatched and high-speed matched segments

... 121

Table 5-4 Distribution of the matched case-control segments for all fatal crashes ... 124

Table 5-5 Distribution of segments for MTW fatal crashes as impacted vehicles for a matched C-C study ... 124

Table 5-6 Descriptive statistics of the study variables of NH 7 ... 126

Table 5-7 Full model results of fatal crashes ... 127

Table 5-8 Estimation of the rear-end only fatal crashes full model ... 129

Table 5-9 Comparison of the estimated ORs of all models. ... 130

Table 5-10 Summary of the parsimonious models for all four crash types ... 132

Table 5-11 Parsimonious models fit summary ... 133

Table 6-1 Summary of the variables for the unmatched and matched segments of all scenarios ... 143

Table 6-2 The number of case and control segments for all three scenarios ... 146

Table 6-3 Comparison of the estimates for all the developed scenario 1 and 2 ... 150

Table 6-4 Estimated ORs for the scenario 3 ... 151

Table 6-5 Results of a matched case-control study to account for multiple crashes (Scenario 2) ... 154

Table 6-6 Summary of the parsimonious models for all the scenarios ... 158

Table 6-7 Summary of the model fit statistics for the parsimonious models ... 160

Table 7-1 Specification of the considered NB models framework in the study ... 173

Table 7-2 Descriptive summary of the study variables of YE ... 175

Table 7-3 Model estimates for fatal rear-end crashes ... 176

Table 7-4 Estimated marginal effects of FPNB, RPNB and CRPNB models ... 178

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Table 7-5 The pairwise correlation values between heterogeneities of the random parameters

... 181

Table 7-6 Summary of the parameter estimates of the re-estimated models ... 182

Table 7-7 Marginal effects and elasticity estimates ... 183

Table 7-8 Covariance and correlation estimates of the random parameter of CRPNB parsimonious model ... 183

Table A-1 Summary of the shoulder width related initiatives for Indian intercity highways 219 Table A-2 Changes in the paved and unpaved shoulder width in India ... 220

Table A-3 Total shoulder width for Indian intercity highways and expressways as per IRC specifications in 2022 ... 221

Table A-4 Highway geometrics and roadside data collection form used in this study ... 222

Table A-5 Highway traffic speed measurement form used in this study ... 224

Table A-6 Highway traffic volume collection form used in this study ... 225

Table A-7 Summary of the traffic volume data for NH 44 ... 226

Table A-8 Summary of the traffic volume collected through the survey on LHS of NH 7 . 229 Table A-9 Summary of the traffic volume collected through the survey on RHS of NH 7 230 Table A-10 Summary of the traffic volume collected through the survey on LHS of NH 44 ... 231

Table A-11 Summary of the traffic volume collected through the survey on RHS of NH 44 ... 232

Table A-12 Summary of the speed collected through the survey on LHS of NH 7 ... 233

Table A-13 Summary of the speed collected through the survey on RHS of NH 7 ... 234

Table A-14 Summary of the speed collected through the survey on LHS of NH 44 ... 235

Table A-15 Summary of the speed collected through the survey on RHS of NH 44 ... 237

Table A-16 Summary of all fatal crashes model estimates of NH 7... 239

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Table A-17 Summary of the variable removed at every step for all fatal crashes models of

NH 7... 240

Table A-18 Summary of model fit statistics for all fatal crashes of NH 7 ... 240

Table A-19 Summary of rear-end only fatal crashes model estimates of NH 7 ... 241

Table A-20 Summary of the variable removed at every step for rear-end only crash models of NH 7... 242

Table A-21 Model fit statistics for rear-end only crash models of NH 7 ... 242

Table A-22 Summary of the slow-moving vehicles and VRUs crash model estimates of NH 7 ... 243

Table A-23 Summary of the variable removed at every step for slow-moving vehicles and VRUs crashes of NH 7 ... 244

Table A-24 Model fit statistics for slow-moving vehicles and VRUs crashes of NH 7 ... 244

Table A-25 Summary of the M2W crashes model estimates of NH 7 ... 245

Table A-26 Summary of the variable removed at every step for M2W crashes models of NH 7 ... 246

Table A-27 Model fit statistics for M2W crashes models of NH 7 ... 246

Table A-28 Summary of all model estimates for scenario 1 ... 247

Table A-29 Summary of the variable removed at every step for scenario 1 ... 250

Table A-30 Summary of the model fit statistics for scenario 1 ... 251

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Table A-37 Summary of fixed parameter NB model estimates (step 2A) ... 259 Table A-38 Summary of random parameters NB model estimates (step 3C) ... 260 Table A-39 Summary of correlated random parameters NB model estimates (step 4) ... 260

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List of Figures

Figure 1-1 RTC risk factors categories. ... 3

Figure 1-2 Decadal CAGR of road accidents, registered vehicles, and road length in India from 1970-2019. ... 7

Figure 1-3 Yearly trend of the number of crashes, fatalities, and injuries in RTC on NHs in India from 1970 to 2019. ... 8

Figure 1-4 Proportion of road category length and road fatalities for each highway category in India. ... 9

Figure 1-5 Fatalities trend for NHs, SHs and Other Roads in India from 2008 to 2019. ... 10

Figure 1-6 Distribution of fatalities of road user type in India. ... 11

Figure 1-7 Illustration of the study methodology. ... 16

Figure 2-1 Summary of the application of the case-control method in highway safety. ... 53

Figure 3-1 Spatial distribution of the surveyed intercity highway stretches based on Google My Maps. ... 56

Figure 3-2 Summary of the total intercity highways (a) distribution of the highways as divided or undivided (b) distribution of the highways based on the number of lanes. ... 62

Figure 3-3 Summary of the cross-sectional element of highways (a) paved shoulder width variation (b) median width variation. ... 63

Figure 3-4 Distribution of the surveyed highway stretches in Punjab (Google My Maps). ... 65

Figure 3-5 Spatial distribution of the selected highway stretches on Google My Maps. ... 67

Figure 3-6 Study highway stretch of NH 7 from Zirakpur to Patiala in Punjab state of India. ... 68

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Figure 3-7 Illustration of the selected six-lane highway stretch of NH 44 in Punjab, India.

NTS means not to scale ... 69

Figure 3-8 Map depicting the selected study stretch of the YE. ... 70

Figure 3-9 The framework of the dataset developed in this study. ... 72

Figure 3-10 (a) Data collection locations on NH 7 (source: Google My Maps) (b) typical cross-section of the studied highway (c) typical cross-section of the studied highway section passing through the village or settlement. (Photo by L S Bisht) ... 73

Figure 3-11 Laser-based speed measuring device used in this study. ... 74

Figure 3-12 (a) Speed data collection on the median side of NH7. (b) Traffic volume data collection on the median of NH 7. ... 75

Figure 3-13 (a) Position of the video camera to collect traffic volume data on NH 44. (b) Speed and volume collection on the median side on NH 44. ... 76

Figure 3-14 Framework for developing dataset in this study. ... 83

Figure 4-1 85^th percentile speed variation of cars and large-size vehicles on the YE. ... 88

Figure 4-2 Yearly distribution of traffic volume on the YE. ... 88

Figure 4-3 Segment-wise distribution of 85^th percentile speed and traffic volume on the YE. ... 89

Figure 4-4 Segment-wise distribution of the cars, large-size vehicles and the total percentage of vehicles violating the speed limit on the YE. ... 90

Figure 4-5 Distribution of all fatal crashes based on collision types on NH 7. ... 93

Figure 4-6 Distribution of slow-moving impacted vehicles and VRUs in fatal crashes. ... 94

Figure 4-7 (a) Comparison of the distribution of the impacting vehicle types (b) Comparison of the distribution of the road users as the occupant of the impacted vehicle and VRUs involved in the fatal crashes. ... 95

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Figure 4-8 Distribution of impacting vehicle type and impacted vehicle type and VRUs in all fatal crashes on NH 7. ... 96 Figure 4-9 Distribution of impacting vehicle type and road users as occupants of the

impacted vehicles and VRUs in all fatal crashes on NH 7. ... 97 Figure 4-10 Distribution of all fatal crashes, rear-end fatal crashes and slow-moving impacted vehicles and VRUs as per the time of the day. ... 98 Figure 4-11 Temporal distribution of all fatal crashes on NH 7 (a) Daily distribution (b) Monthly distribution. ... 99 Figure 4-12 Distribution of all fatal crashes based on collision types on NH 44. ... 100 Figure 4-13 Distribution of the impacting vehicle type and road users involved in the fatal crashes on NH 44. ... 101 Figure 4-14 Distribution of impacting vehicle type and road users as occupants of the impacted vehicles and VRUs in all fatal crashes on NH 44. ... 101 Figure 4-15 Distribution of the impacting vehicle type and road users involved in the fatal crashes on NH 44. ... 102 Figure 4-16 Distribution of the impacting vehicle type and road users involved in the fatal crashes on NH 44. ... 103 Figure 4-17 Temporal distribution of all fatal crashes on NH 44 (a) Daily distribution (b) Monthly distribution. ... 103 Figure 4-18 Distribution of the number of fatal crashes (a) Number of total fatal crashes and rear-end fatal crashes (b) Number of fatalities in the total fatal crashes and in rear-end fatal crashes. ... 105 Figure 4-19 Distribution of the total fatal crashes based on collision types. ... 105 Figure 4-20 Yearly distribution of the total fatal crashes based on collision types. ... 106

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Figure 4-21 Distribution of the impacting vehicle type involved in total fatal and rear-end only fatal crashes. ... 106 Figure 4-22 Distribution of the impacting vehicles and types of road users as occupants of the impacted vehicles in rear-end crashes. ... 107 Figure 4-23 Distribution of the impacting vehicles and types of road users as occupants of the impacted vehicles in total fatal crashes. ... 108 Figure 4-24 Comparison of the road users involved in the YE. ... 109 Figure 4-25 Temporal distribution of all fatal crashes on NH 7 (a) Daily distribution (b) Monthly distribution. ... 110 Figure 5-1 (a) Typical design procedure of a C-C study (b) Case-control method application analogy between epidemiology and highway safety. (Adapted from Gordis, 2014) ... 118 Figure 5-2 Results showing the variation of OR for paved shoulder width. ... 131 Figure 6-1 (a) Illustration of data collection locations on NH 44 (source: Google My Maps);

(b) Typical cross-sections of the studied six-lane highway. (Photo by L.S. Bisht) ... 141 Figure 6-2 Methodology to assess RTC risk in segments with multiple fatal crashes. ... 145 Figure 6-3 Comparison and variation in OR for paved shoulder width categories between scenarios 1 and 2. ... 152

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List of Abbreviations

Abbreviation Definition

AADT annual average daily traffic

AASTHO The American Association of State Highway and Transportation Officials

ADT average daily traffic

ASA American Statistical Association ATCC automatic traffic counter and classifier

B-A Before-after

CAGR compound annual growth rate

C-C Case-control

CI confidence intervals

CMFs crash modification factors

CRPNB correlated random parameter negative binomial EASTS Eastern Asia Society for Transportation Studies

EB empirical Bayes

FHWA The Federal Highway Administration FIR first information report

FPNB fixed parameter negative binomial

GBD Global Burden of Disease

GDP gross domestic product

GIS geographic information system

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GQ Golden quadrilateral

GVA gross value addition

HIC high-income countries

HSM The Highway Safety Manual

IHMCL Indian Highways Management and Corporation Limited

IPC Indian Penal Code

IRC Indian Roads Congress

LASER light amplification by stimulation emission of radiation LCVs light commercial vehicles

LHS left-hand side

LMIC low-and middle-income countries

MATLAB MATrix LABoratory

MLE maximum likelihood estimation

MoRTH Ministry of Road Transport and Highways

MTW motorized two-wheelers

MVA Motor Vehicles Act

M3W motorized three-wheeler

NB negative binomial

NCHRP The National Cooperative Highway Research Program

NHs national highways

NHAI National Highways Authority of India NHDP National Highways Development Project

NHIDCL National Highways and Infrastructure Development Corporation Limited

NLOGIT nested logit

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NMV non-motorized vehicle

OR odds ratio

PDO property damaged only

Prob probability

PS propensity score

RCTs randomized control trials

RHS right-hand side

RTIs road traffic injuries

ROR run-off-road

RPNB random parameter negative binomial RTCs road traffic crashes

RTI road traffic injuries

SDGs sustainable development goal

SE standard error

SH state highway

SPFs safety performance functions SVCs single-vehicle crashes

SW Shoulder width

TRID Transport Research International Documentation

UN United Nations

UP Uttar Pradesh

US United States

VKT vehicle kilometres travelled VMT vehicle miles travelled VRUs vulnerable road users

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WHO World Health Organisation

YE Yamuna Expressway

YEIDA Yamuna Expressway Industrial Development Authority

2L Two-lanes

4L Four-lanes

6L Six-lanes