Abstract

The problem of minor vehicles crossing or merging into the major stream at unsignalized priority-controlled intersections is well-known. Numerous solutions involve various assumptions concerning the major headway distributions, number of major lanes, critical gap distributions, etc. Such cases can be divided into two main groups: intersections with two streams (one major and one minor stream) and intersections with more than two streams (more than one major stream and one minor stream). At roundabouts, also at single-lane roundabouts, there are similar problems like the ones at other unsignalized priority-controlled intersections. A vehicle at the roundabout approach can only cross the pedestrian crossing when a sufficient time-gap between two pedestrians (or cyclists) is provided. A vehicle at the roundabout entries can only merge into the major stream when a sufficient gap between the two vehicles in the major stream is provided. Because of that, single-lane round-abouts can also be treated as unsignalized intersections with two major lanes: the first one in its circulatory roadway and the second one on the pedestrian crossing. Problematika križanja ali vključevanja stranskega prometnega toka v nivojskih križiščih, kjer je prometni režim urejen z glavno in stransko prometno smerjo, je znan. Številni pristopi vsebujejo različne predpostavke, ki zadevajo porazdelitev glavnega prometnega toka, število prometnih pasov na glavni prometni smeri, kritično časovno praznino ... Take sisteme lahko razdelimo v dve glavni skupini: križišča z dvema tokoma (enim glavnim in enim stranskim) in križišča z več kot dvema tokoma (več kot dva glavna prometna toka in en stranski prometni tok). V krožnih križiščih, tudi v enopasovnih, obstajajo enaki problemi, kot pri drugih nivojskih križiščih, urejenih s prometnim režimom glavne in stranske prometne smeri. Vozilo na uvozu v krožno križišče se lahko priključi v glavni prometni tok le v primeru, ko je časovni presledek med dvema pešcema (ali kolesarjema) zadosti velika. Vsled tega lahko tudi enopasovna krožna križišča obravnavamo kot nesemaforizirana križišča z dvema glavnima prometnima tokoma: prvim v krožnem vozišču in drugem na prehodu za pešce.

Abstract

The core city in Pune is highly congested, and the number of motorised vehicles on the street is increasing rapidly in the whole city. This creates problems like air pollution, high noise levels, long travelling times and an unpleasant urban environment etc. The thesis presents some solutions for these problems, based on sustainable transport principles, methods for creating a pleasant walking environment and best practice examples. The planning proposal is divided into a concept plan for the whole core city, as well as a detailed planning proposal for a pedestrian street on a part of Laxmi Road - one of Pune’s most well-known streets. Different aspects of the core city area and Laxmi Road have been mapped thoroughly and a traffic count, function analysis, a target point analysis and a Lynch analysis have been performed. Focus is to improve conditions for pedestrians. To achieve this it is important to limit the motorised traffic. An origin- destination survey performed on Laxmi Road displayed that over 40% of the traffic on the street in peak-hour is through traffic. The proposal is therefore to limit through traffic and improve the pedestrian environment. This thesis evaluates and discusses this proposal; including an analysis of the improvements to the air quality, the effect on different groups of people, and the necessary elements for the project to succeed.

Abstract

Contrary to traditional thinking and driver intuition, here we show that there is no benefit to ground vehicles increasing their packing density at stoppages. By systematically controlling the packing density of vehicles queued at a traffic light on a Smart Road, drone footage revealed that the benefit of an initial increase in displacement for close-packed vehicles is completely offset by the lag time inherent to changing back into a ‘liquid phase’ when flowresumes. This lag is analogous to the thermodynamic concept of the latent heat of fusion, as the ‘temperature’ (kinetic energy) of the vehicles cannot increase until the traffic ‘melts’ into the liquid phase.These findings suggest that in situations where gridlock is not an issue, drivers should not decrease their spacing during stoppages in order to lessen the likelihood of collisions with no loss in flowefficiency. In contrast, motion capture experiments of a line of people walking from rest showed higher flow efficiency with increased packing densities, indicating that the importance of latent heat becomes trivial for slower moving systems. Department of Biomedical Engineering and Mechanics at Virginia Tech Institute for Creativity, Arts, and Technology Document type: Article

Abstract

To provide protection to pedestrians in collision with passenger vehicles, the design and construction of a vehicle’s bumper, hood and fender panels must be addressed. TNO has undertaken a research project in conjunction with DSM to investigate how this may be done. Vehicle styling, packaging and an analysis led design process will be shown for the front of the vehicle and in particular the hood and bumper. The recommendations of EEVC working group 10 are used as a target to asses the design proposal’s suitability.

Abstract

With self-driving vehicles (SDVs), pedestrians can no longer rely on a human driver. Previous research suggests that pedestrians may benefit from an external Human–Machine Interface (eHMI) displaying information to surrounding traffic participants. This paper introduces a natural methodology to compare eHMI concepts from a pedestrian’s viewpoint. To measure eHMI effects on traffic flow, previous video-based studies instructed participants to indicate their crossing decision with interfering data collection devices, such as pressing a button or slider. We developed a quantifiable concept that allows participants to naturally step off a sidewalk to cross the street. Hidden force-sensitive resistor sensors recorded their crossing onset time (COT) in response to real-life videos of approaching vehicles in an immersive crosswalk simulation environment. We validated our method with an initial study of N = 34 pedestrians by showing (1) that it is able to detect significant eHMI effects on COT as well as subjective measures of perceived safety and user experience. The approach is further validated by (2) replicating the findings of a test track study and (3) participants’ reports that it felt natural to take a step forward to indicate their street crossing decision. We discuss the benefits and limitations of our method with regard to related approaches. Document type: Article

Abstract

Worldwide, it is estimated that every year 1.2 million road users lose their lives on road crashes. This situation has a huge impact in terms of health and economical development and costs to governments. Pedestrians and cyclists, often called vulnerable road users (VRUs), are more likely to be injured in road crashes as they are unprotected and more exposed to risk in the presence of motor vehicles. In 2015, 21% of the fatalities in European Union’s roads were pedestrians, while 8% were cyclists. The respective percentages in Portugal were 23% for pedestrians and 5% cyclists. The objective of the paper is to developed a comprehensive study between motor vehicle and pedestrians or cyclists collisions occurrences integrating spatio-temporal data analysis with crash prediction models. Spatial analysis is the first step to identify the patterns between blackspots in three cities from Portugal (Aveiro, Porto and Lisbon). Blackspots were identified using ArcGIS and the Kernel Density Estimation function taking into account the level of injury severity. The second step is a temporal analysis that involves a temporal distribution of the crashes or injured people. Lastly, a crash prediction model was developed for each city that calculates the likelihood of VRUs to be involved in a crash taking into account injury severity. The findings from the study highlighted target variables and specificities at a local level that may influence the number and severity of crashes between motor vehicle and VRUs. The identification of blackspots revealed that most injuries occurs surrounding high attraction places. Temporal analysis results showed a major percentage of crashes occurring during afternoon peak-hours (4-7p.m.). Comparison between the cities showed that Porto presents the worst scenario in terms of number of VRUs injuries per ten thousand inhabitants or kilometers squared. The developed Multinomial Logistic Regression models revealed that VRU gender and age, as well as weather conditions, are statistically significant for the prediction models. The spatio-temporal analysis of crashes taking into account the level of injury severity has the goal of establishing patterns between the different cities, which is important to understand risk factors. The outcomes of the study are valuable not only for VRUs awareness, but also for traffic planners and decision-makers.

Abstract

most half of all traffic fatalities worldwide are non-motorised road users (NMRUs). In Denmark, the number has increased with about 30%. NMRUs consist of about 63% of the injured in the Danish traffic. Much has been done to reduce the number of injured NMRUs with counterparts, while little effort is put into the reduction of the vast majority of the accidents, NMRU single accidents, which are about 90% of all injured NMRUs. There are no efficient tools available to reduce this number. A significantly better designed, maintained, and illuminated road network would most likely help. However, that is expensive and not possible for most road authorities. Despite this, the challenges with NMRUs in single accidents need more attention, if road safety is to be improved. The situation in Denmark is more than likely the case in many other countries as well; although the documentation is scarce. Almost half of all traffic fatalities worldwide are non-motorised road users (NMRUs). In Denmark, the number has increased with about 30%. NMRUs consist of about 63% of the injured in the Danish traffic. Much has been done to reduce the number of injured NMRUs with counterparts, while little effort is put into the reduction of the vast majority of the accidents, NMRU single accidents, which are about 90% of all injured NMRUs. There are no efficient tools available to reduce this number. A significantly better designed, maintained, and illuminated road network would most likely help. However, that is expensive and not possible for most road authorities. Despite this, the challenges with NMRUs in single accidents need more attention, if road safety is to be improved. The situation in Denmark is more than likely the case in many other countries as well; although the documentation is scarce.

Abstract

the desire for deploying automated (“driverless”) vehicles increases, there is a need to understand how they might communicate with other road users in a mixed traffic, urban, setting. In the absence of an active and responsible human controller in the driving seat, who might currently communicate with other road users in uncertain/conflicting situations, in the future, understanding a driverless car’s behaviour and intentions will need to be relayed via easily comprehensible, intuitive and universally intelligible means, perhaps presented externally via new vehicle interfaces. This paper reports on the results of a questionnaire-based study, delivered to 664 participants, recruited during live demonstrations of an Automated Road Transport Systems (ARTS; SAE Level 4), in three European cities. The questionnaire sought the views of pedestrians and cyclists, focussing on whether respondents felt safe interacting with ARTS in shared space, and also what externally presented travel behaviour information from the ARTS was important to them. Results showed that most pedestrians felt safer when the ARTS were travelling in designated lanes, rather than in shared space, and the majority believed they had priority over the ARTS, in the absence of such infrastructure. Regardless of lane demarcations, all respondents highlighted the importance of receiving some communication information about the behaviour of the ARTS, with acknowledgement of their detection by the vehicle being the most important message. There were no clear patterns across the respondents, regarding preference of modality for these external messages, with cultural and infrastructural differences thought to govern responses. Generally, however, conventional signals (lights and beeps) were preferred to text-based messages and spoken words. The results suggest that until these driverless vehicles are able to provide universally comprehensible externally presented information or messages during interaction with other road users, they are likely to contribute to confusing and conflicting interactions between these actors, especially in a shared space setting, which may, therefore, reduce efficient traffic flow.