Drivers overtaking cyclists on rural roads create a hazardous scenario due to the potentially high impact speeds and, therefore, severe consequences in case of a crash [1]. Díaz Fernández et al. analyzed crashes between cyclists and motorized vehicles from various data sources, including insurance reports and crash databases, and concluded that this scenario is particularly dangerous and new safety countermeasures are needed [2]. Other studies have shown that particularly the side-swipe risk through. aerodynamic forces due to low lateral clearance and high overtaking speed affects both the objective and subjective safety of the cyclist [3], [4]. Furthermore, recent work by Gildea et al. showed through a self-reported survey among cyclists that a significant amount of side-swipe crashes and near-crashes with lower severity of injuries remains unreported [ 5]. This underlines the importance of investigating further in what situations the side-swipe risk for cyclists increases and how it can be decreased effectively. Previous research investigated how driver behavior in overtaking is influenced by infrastructural elements such as lane widths [6], road markings [6], [7], parked cars [7], and the presence of road crossings. However, the effect of sight distance on driver behavior has not gained much attention yet. Therefore, this work analyzed the influence of sight distance on driver behavior and the resulting safety implications for the overtaken cyclist.

Cyclists as vulnerable road users are oftentimes unprotected with exposed human body, can fall easily and sustain serious injuries when encountered collisions, especially with motorists. At roundabouts, accident reduction rate for cyclists is rather uncertain or sometimes less favorable compared to other road users (e.g. motorists, pedestrians). This thesis focuses on advancing the understanding of traffic safety issues for cyclists at roundabouts by identifying concerns faced by cyclists and evaluating their designs to find out which configuration has high or higher safety level towards cyclists. The research approach adopted in this work includes a wide review of relevant literature on cyclist safety and roundabouts and the implementation of empirical research, the latter was carried out through a Case Study in Norrköping city by obtaining cyclist related accident data from Swedish Traffic Accident Data Acquisition database to identify roundabouts with high cyclist-related accidents in the city assisted with PTV Visum Safety tool and fetching traffic volume from city network model operated by Norrköping Municipality for each identified roundabout. The main findings from this research conclude that single-lane roundabouts with separated cycle paths in high traffic volume setting provide better or higher safety performance for cyclists compared to other roundabout configurations.

The road transport in Kenya is the most common means oftransport for people living in both urban and rural areas. The use of bicycles for transport dates back in the pre-colonial time and has been used as a mode of transport until 2008 when the use of motorcycles became a popular mode of travel in the rural and urban areas. However, the use of bicycle as a means of travel has declined consistently over the years until now and many have shifted to the use of car, public transport and most commonly motorcycles which are popularly known as 'boda boda' in Kenya. This modal shift can be attributed to a number of factors identified as challenges in the use of bicycles as a common mode of transport in comparison to other emerging modes of transport both in rural and urban areas. However, despite this modal shift, there are a substantial number of road users who would still prefer to use the bicycle mode amid prevalence in road traffic fatalities and injuries in Kenya. The government of Kenya has established initiatives to provide safe and inclusive transport system by investing in transport infrastructure that includes cycle tracks especially for roads located in the urban cities. This has been enabled by innovation in design, mixed traffic composition, change of legislation and road design standards especially in regards to non-motorized transport in Kenya. Cycling is still low in cities in Kenya despite this effort to improve geometric design of roads. This paper explores these challenges and opportunities in cycling in Kenya focusing on Nairobi city as a case study. [From: Introduction]

This thesis comprises two studies that investigated bike infrastructure safety in North America. The first study conducted a corridor-level analysis to quantify the safety of different bike infrastructure types and assess the influence of corridor-specific characteristics on their performance. Using a Poisson-lognormal Full Bayesian model, the study analyzed fatal and injury bike-vehicle collisions on over 7800 corridors in Toronto, Canada. The findings revealed that bike infrastructure effectively reduces bike collisions, with cycle tracks demonstrating superior safety benefits due to the physical separation of cyclists from vehicular traffic. Cycle tracks were found to be particularly effective on long corridors with fewer intersections as bike-vehicle interactions along the corridor are minimized. Signed routes were safe on low-volume and low-speed roads, while bike lanes are more suited for a short section of high-volume corridors with a high intersection density. The second study assessed the safety of parking-protected bike lanes (PPBL), a new concept that is rapidly growing in North America. Utilizing data from nineteen street sections in Vancouver and Ottawa, the study developed a Full Bayesian Before-and-after model to evaluate the safety impacts of converting traditional painted bike lanes to PPBLs. The results indicated a significant reduction of 31.2% in total collisions after PPBL implementation. However, the effects of PPBLs on cyclist safety were found to be sensitive to factors such as bike path opening density, intersection density, and intersection treatments. In roads where proper intersection treatments and minimal protection of PPBL openings can be provided, painted bike lanes can be converted into PPBLs, and significant safety benefits can be expected. The findings of this thesis offer practical guidance for city planners and policymakers regarding the safety implications of different bike infrastructure types and the most appropriate conditions to implement them, which supports bike safety enhancement initiatives and attracts more people to bike. / Thesis / Master of Applied Science (MASc) / This thesis presents two studies that offer valuable insights to improve bike safety. The first study examined the safety of various bike infrastructure types along with the impact of corridor characteristics on their performance. The findings emphasized the effectiveness of cycle tracks in reducing collisions on long corridors with fewer intersections. Signed routes were found to be effective on low-volume and low-speed roads, while bike lanes were ideal on short sections of high-volume roads with a high intersection density. The second study assessed the impacts of new designed concept, known as the parking-protected bike lanes (PPBLs). The study showed that converting painted bike lanes to PPBLs significantly reduced total collisions. However, proper treatment of intersection and bikeway openings is crucial for enhancing cyclist safety and reducing multi-vehicle rear-end collisions. Where proper intersection treatment and minimal protection of bikeway openings can be provided, bike lanes can be safely converted into PPBLs.

La littérature sur la sécurité cycliste présente des résultats parfois contradictoires, car l’utilisation des mesures d’exposition est peu fréquente. Ce mémoire de maîtrise cherche à décrire les mesures d’exposition et la méthodologie associée dans le calcul du risque de blessures chez les cyclistes dans le contexte québécois, ainsi que montrer l’impact de leur utilisation. D’abord une revue narrative quasi-systématique sur les mesures d’exposition aidant à préciser leur utilisation dans le calcul du taux d’incidence de blessures chez les cyclistes est effectuée en incluant les concepts de sécurité, du vélo et des mesures d’exposition. Puis, des mesures d’exposition sont utilisées pour comparer les taux d’incidence de blessures à vélo obtenus dans deux régions du Québec, soit l’Outaouais et Laval, qui se distinguent considérablement au regard de la proportion de port du casque chez les cyclistes et au regard de la quantité d’infrastructures cyclables totales disponibles. Des taux d’incidence des blessures à la tête et blessures totales chez les cyclistes sont calculés pour ces deux régions en utilisant au dénominateur une mesure de fréquence populationnelle et des mesures d’exposition (distance, déplacements, nombre de cyclistes). Les régions sont comparées entre elles en calculant les ratios de taux d’incidence. Les ratios de taux d’incidence utilisant les mesures de fréquence populationnelle montrent peu de différence pour les blessures chez les cyclistes entre les deux régions, alors que les ratios calculés avec les trois mesures d’exposition montrent la région de Laval comme étant plus à risque. Ceci montre l’impact de l’utilisation des mesures d’exposition dans les études de sécurité cycliste. / Cyclists’ safety literature often presents contradictory findings. Infrequent use of exposure in those studies is one reason why. This work aims to describe how to use exposure variables to calculate cyclists’ injury incidence rate in the province of Quebec. A quasi-systematic narrative review on exposure variable in the context of safety of bicyclists was conducted to guide their use. Then, exposure variables were used to compare the incidence rates of head and total injuries between the regions of Outaouais and Laval. These two regions were chosen because they differ in helmet usage and quantity of cycling infrastructures. Incidence rates for head and total injuries were calculated for both regions by controlling population frequency and three exposure variables (distance, trips and number of cyclists). Both regions were compared with incidence rate ratios. The incidence rate ratios using population frequency showed little to no difference in safety between both regions, while those using exposure variables showed that Laval presented greater risks for cyclists. These results show the importance of using exposure in safety studies for cyclists.

Cycling has always been considered a sustainable and healthy mode of transport. Moreover, during Covid-19 period, cycling was further appreciated. by citizens as an individual opportunity of mobility. As a counterpart of the growth in the num.ber ofbicyclists and of riding k:ilometres, bicyclist safety has become a challenge as the unique road transport mode with an increasing trend of crash fatalities in EU (Figure 1). When compared to the traditional road safety network screening. availability of suitable data for crashes involving bicyclists is more difficult because of underreporting and traffic flow issues. In such framework, new technologies and digital transformation in smart cities and communities is offering new opportunities of data availability which requires also different approaches for collection and analysis. An experimental test was carried out to collect data ftom different users with an instrumented bicycle equipped with Global Navigation Satellite Systems (GNSS) and cameras. A panel of experts was asked to review the collected data to identify and score the severity of the safety critical events (CSE) reaching a good consensus. Anyway, manual observation and classi.fication of CSE is a time consu.ming and unpractical approach when large amount of data must be analysed. Moreover, due to the complex correlation between precrash driving behaviour and due to high dimensionality of the data, traditional statistical methods might not be appropriate in t.bis context. Deep learning-based model have recently gained significant attention in the lit.erature for time series data analysis and for anomaly detection, but generally applied to vehicles' mobility and not to micro-mobility. We present and discuss data requirements and treatment to get suitable infonnation from the GNSS devices, the development of an experimental :framework: where convolutional neural networks (CNN) is applied to integrate multiple GPS data streams of bicycle kinematics to detect the occurrence of a CSE.

While cycling is promoted as a sustainable and healthy mode of transport in many eitles in the Global North [1, 2], there are increasing concerns about the safety of cyclists. The increasing bicycle use in urban areas leads to a more intensely used cycling network, resulting in safety risks for cyclists [3]. Since 2010, the number of bicycle fatalities stagnated and the number of severely injured cyclists increased by 28% until 2018 in the European Union [4]. lt is therefore necessary to examine how bicycle use and motorized vehicle use in cities affects the nunber of bicycle crashes. To investigate this, the effect of the network-wide hourly exposure to cyclists and motorized vehicles on bicycle crash frequency is examined. That is, the total number of cyclists and motorized vehicles in the whole road network for each hour of the week were estimated and used as the network-wide hourly exposure. This approach allowed us to capture safety impacts of temporal variation in the numbers of cyclists and motorized vehicles in the same network more accurately. lt is a different approach compared to most bicycle safety studies, which often only use the daily average of bicycle and motorized vehicle volumes. The work presented here is based on our publication in Safety Science [5].

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