An Investigation into the Appropriateness of Car-Following Models in Assessing Autonomous Vehicles

The dramatic progress of Intelligent Transportation Systems (ITS) has made autodriving technology extensively emphasised. Various models have been developed for the aim of modelling the behaviour of autonomous vehicles and their impacts on traffic, although there is still a lot to be researched about the technology. There are three main features that need to be represented in any car-following model to enable it to model autonomous vehicles: desired time gap, collision avoidance system and sensor detection range. Most available car-following models satisfy the first feature, most of the available car-following models do not satisfy the second feature and only few models satisfy the third feature. Therefore, conclusions from such models must be taken cautiously. Any of these models could be considered for updating to include a collision avoidance-system module, in order to be able to model autonomous vehicles. The Helly model is car-following model that has a simple structure and is sometimes used as the controller for Autonomous Vehicles (AV), but it does not have a collision avoidance concept. In this paper, the Helly model, which is a very commonly used classic car-following model is assessed and examined for possible update for the purpose of using it to model autonomous vehicles more efficiently. This involves assessing the parameters of the model and investigating the possible update of the model to include a collision avoidance-system module. There are two procedures that have been investigated in this paper to assess the Helly model to allow for a more realistic modelling of autonomous vehicles. The first technique is to investigate and assess the values of the parameters of the model. The second procedure is to modify the formula of that model to include a collision avoidance system. The results show that the performance of the modified full-range Auto Cruising Control (FACC) Helly model is superior to the other models in almost all situations and for almost all time-gap settings. Only the Alexandros E. Papacharalampous’s Model (A.E.P.) controller seems to perform slightly better than the (FACC) Helly model. Therefore, it is reasonable to suggest that the (FACC) Helly model be recommended as the most accurate model to use to represent autonomous vehicles in microsimulations, and that it should be further investigated

Saudi Women and Vision 2030: Bridging the Gap?

(1) Background, Travel characteristics of Saudi women contrast significantly from those in the west. This is not only because they have different culture, attitudes and preferences but also until recently, Saudi women were not allowed to drive. In 2018, they were granted the right to drive. It has been anticipated that enabling women to drive will improve their mobility and employability. (2) Methods: This study presents a qualitative study into factors affecting Saudi women’s travel decisions “before” and “after” enabling women to drive in the Kingdom. Two six “before” and “after” focus groups have been carried out to investigate the decision-making process associated with Saudi women’s travel, available options of travel and perception of Saudi women towards private car driving. (3) Results: The results reveal that main travelling options for professional and high-income women is a private driver in the “before” scenario and a ride-share option with a family member. In the “after” scenario, high income professional women prefer “drive own car” option. Moreover, many of the participants indicated that it is likely that they might keep private drivers as well. (4) Conclusion. The results from this research indicate that there has been significant change in travel characteristics, attitudes and behaviour of Saudi women since they were granted the right to drive. This is likely to have significant implications for decision and policy makers. Further research into potential impacts of the current situation on car ownership and use, impacts on public transport system, environmental impacts and sustainability is needed

Gender and Equality in Transport. Proceedings of the 2021 Travel Demand Management Symposium

Proceedings of the 10TH INTERNATIONAL TRAVEL DEMAND MANAGEMENT (TDM) SYMPOSIUM IN CONJUNCTION WITH TINNGO AND DIAMOND FINAL CONFERENCE titled: Gender and Equality in Transpor

Pedestrian Road Crossing at Uncontrolled Mid-Block Locations: Does the Refuge Island Increase Risk?

The study investigates the behaviour of pedestrians crossing a road with a refuge island in an urban area to assess whether refuge islands deliver their expected benefit. This type of pedestrian crossings aims at providing a half-way shelter and protection while pedestrians are crossing a road with two-traffic streams. Data has been collected using two video cameras from an urban location in Edinburgh on gaps in traffic flow, rejected and accepted gaps, and critical gaps of pedestrians while crossing from the curb or the median. Data have also been examined to estimate and assess vehicle and pedestrians’ speeds, vehicle type, waiting time, group size and other demographic characteristics of pedestrians. The statistical modelling techniques used include Multiple Linear Regression and Generalised Estimating Equations (GEE). The results show that the critical gap for crossing from the median to the curb is much shorter than that from the curb to the median. Pedestrians appear to be less cautious when crossing from the median to the curb as they are more likely to accept a shorter gap in traffic. This could indicate a shortfall in the design and/or operation of this type of crossing. Further considerations and investigation of what measures could be implemented to enhance safety and reduce risky behaviour at this type of crossing are recommended and certainly encouraged

Evaluation of Turkish oregano (Origanum onites L.) under organic farming system

Spice production is crucial for the world economy. Today, the farming of spices faces significant challenges under climate change, such as heat stress, rising salinity, water stress, low soil nutrients, and increased pests, which lead to reduced yield and quality. The present study was conducted in Egypt on Turkish oregano (Origanum onites L.) plants. The trial was achieved under organic farming conditions. The purpose was to investigate the responses of the plant towards two natural stimulators, chitosan and biofertilizer. The design of the work was a split plot. Main plots were assigned to the foliar spray of chitosan at three concentrations (0, 5, and 10 liters/hectare) and sub-plots to biofertilizer EM (with and without). The collected data comprised plant height, fresh and dry herb weights per plant, fresh and dry herb yields per hectare, essential oil percentage, oil yield per plant and hectare, and GC-MS analysis of oils. The significant maximum growth and yield characteristics were obtained by spraying with chitosan at the highest concentration of 10 liters/hectare combined with soil drenching by biofertilizer EM. The major essential oil component was carvacrol, which is responsible for its pungent flavour. This previous treatment also recorded the maximum carvacrol percent in oil of all cuts. So, this treatment could be used to increase the quantity and quality of the organic product

The role of personal norms in the choice of mode for commuting

Research in travel behavioural studies have shown that social forces play a significant role in travel decision making like socioeconomic factors. Several studies have tested models with different subjective variables to investigate their effects on travel behaviour. Understanding the influence of social norm and personal norm on travel mode choice preference is essential in promoting sustainable travel, considering the reported importance of these social forces in decision-making. This study draws upon the theories underpinning these sociological constructs and the integrated choice and latent variable (ICLV) framework to develop an ICLV model by incorporating social norm and personal norm as latent variables to investigate their impact on transport mode choice decisions. The results of the ICLV model is consistent with the findings in similar studies and extend the literature in transport mode choice modelling. The results indicate that internalised norms or personal norms have a significant influence on individual behaviour, and positively influence travel behaviour. This strengthens the claim that activated norms and pro-environmental behaviour (PEB) influence overt behaviour by inducing a sense of obligations to act. The results also suggest that individuals with pro-environmental attitude are likely to travel with sustainable travel modes. Thus, reinforcing the importance of sociological and psychological factors in decision-making. Unlike studies involving social norms and personal norms, this research is novel because it applies the ICLV framework to empirically investigate the impact of these sociological constructs on travel mode choice behaviour by incorporating them as latent variables in an ICLV model. The contribution of this study to the literature is that it shows that personal norm has a substantial positive impact on sustainable travel. The impact of this study could be situated in the framework of sustainable transport. The findings are relevant for policymaking, the development of policies meant to create awareness of the consequences of travel behaviour could promote the development of strong personal norms, and consequently influence travel decision making. This can be useful for promoting sustainable travel as the findings shed light on the characteristics of individuals most likely to travel by active modes or PT

Histological, immunohistochemical and ultrastructural study of secondary compressed spinal cord injury in a rat model

Introduction. Spinal cord injury (SCI) is a life-disrupting condition in which the first few days are the most critical. Secondary conditions remain the main causes of death for people with SCI. The response of different cell types to SCI and their role at different times in the progression of secondary degeneration are not well understood. The aim of this study was to study the histopathological changes of compressed spinal cord injury (CSCI) in a rat model. Material and methods. Forty adult male Sprague-Dawley rats were divided into four groups. In group I, the rats were left without any surgical intervention (control). In group II, the rats were subjected to laminectomy without spinal cord compression (sham-operated). In group III, the rats were sacrificed one day after CSCI. In group IV, the rats were sacrificed seven days after CSCI. The light microscopy was employed to study the morphology using H&E, osmic acid staining and immunohistochemistry to detect glial fibrillary acidic protein (GFAP). The electron microscopy was applied for ultrastructure study. Results. Histopathological examination of the posterior funiculus of the white matter revealed minute hemorrhages and localized necrotic areas on day 1, which transformed to areas of cavitation and fibrinoid necrosis surrounded by a demarcating rim of numerous astrocytes by day 7. The mean percentage of area of GFAP expression increased significantly by day 7. Osmic acid staining revealed swollen nerve fibers after one day, while numerous fibers had been lost by day 7. An ultrastructure study revealed swollen redundant thinned myelin and myelin splitting, as well as degeneration of axoplasm on day 1. On day 7, layers of the myelin sheath were folded and wrinkled with partial or complete demyelination areas. The myelin lamellae were disorganized and loose. The G-ratio was significantly greater on day 1 than day 7 after CSCI. Conclusions. In the rat model of CSCI details of the progressive spinal cord injury can be analyzed by morphological methods and may be helpful in the identification of the onset and type of clinical intervention

Understanding transport mode choice for commuting: the role of affect

This study examines the relationship between positive and negative user valence and transport mode choice behaviour. We integrate latent attitudes ‘affect’ and ‘salience’ into transport mode choice models using the framework of integrated choice and latent variable modelling and simultaneous maximum likelihood estimation methods. The results are consistent with findings in similar travel behaviour and behavioural economics literature. The study extends the findings of previous research and has demonstrated that user sentiments about public transport mode and salient public transport experiences have a significant impact on travel mode choice behaviour. It was found that private motorised users are more sensitive to overcrowding and anti-social behaviours on PT than active and PT travellers. Key attitudinal indicators influencing individual transport choice behaviour are established to guide public policy. The key indicators of Affect and Salience must be analysed and addressed through public policy to enhance PT user experience and develop services and facilities to increase the utility of PT in-vehicle travel time

Investigation of Critical Gap for Pedestrian Crossing Using Fuzzy Logic System

This paper assesses pedestrian crossing behavior and critical gaps at a two-way midblock crossing location. A critical gap is the shortest gap that a pedestrian accepts when crossing a road. A dataset was collected in 2017 in Edinburgh (UK). The analysis was performed using the fuzzy logic system. The adopted membership function of the fuzzy logic system is of a triangular form since it has a simple and convenient structure. The input variables that are used in the analysis are the number and length of rejected gaps and length of accepted gaps at the crossing location. The output variables are the critical gaps. The results show that assessing critical gap estimation of pedestrians crossing using fuzzy logic is achievable and produces reasonable values that are comparable to values that are reported in the literature. This outcome improves the understanding of pedestrian crossing behavior and could therefore have implications for transport infrastructure design. Further analysis using additional parameters including waiting time and demographic characteristics and alternative forms for membership functions are strongly encouraged