A safe speed guidance model for highways

ABSTRACT

This paper presents a fuzzy logic model to support decisions for the suggested speed limit for sections of highways as they become affected by adverse road conditions, environmental factors and differing traffic levels. The definition of the main factors, and their weight, that reduce safety on highways was conducted by the Delphi method, consulting traffic engineering experts. The survey served as a basis for structuring indicators and indexes in a soft decision tree, structured by a fuzzy logic system. The system can be used to support the decisions of those that manage the roads, indicating to drivers’ speeds, by visual, audible or combined systems.     

The impact of traffic sign deficit on road traffic accidents in Nigeria

This study assesses the impact of traffic sign deficit on road traffic accidents in Nigeria. The participants were 720 commercial vehicle drivers. While simple random sampling was used to select 6 out of 137 federal highways, stratified random sampling was used to select six categories of commercial vehicle drivers. The study used qual-dominant mixed methods approach comprising key informant interviews; group interviews; field observation; policy appraisal and secondary literature on traffic signs. Result shows that the failure of government to provide and maintain traffic signs in order to guide road users through the numerous accident black spots on the highways is the major cause of road accidents in Nigeria. The study argues that provision and maintenance of traffic signs present opportunity to promoting safety on the highways and achieving the sustainable development goals.     

Study on mobile phone use while driving in a sample of Iranian drivers

The use of cell phone is a significant source of driver distraction. Phone use while driving can impair a number of factors critical for safe driving which can cause serious traffic safety problems. The objective of this paper was to investigate the frequency of using cell phones while driving in Iran's roads through an observational survey with a random sample of drivers, to recognize contributing factors to cell phone usage and to understand the magnitude of the problem. A total of 1794 observations were collected from 12 sites at controlled intersections, entrance and exit points of highways. The cell phone use rate among drivers (talking or texting) was estimated at 10% which is significantly higher than that in other countries such as Australia, USA and Canada. Rate of cell phone use among younger drivers (14.15%) was higher in comparison with other groups. In order to identify factors affecting cell phone use while driving, a binary logit model is estimated. Variables which significantly contribute to the rate of using cell phone were found to be the age of driver, number of passengers, presence of kids under the age of 8, time of observation, vehicle price and type of car.     

Investigation of pedestrian crashes using multiple correspondence analysis in India

Abstract

Pedestrian safety is of growing concern with an increasing number of traffic accidents, especially in developing economies like India. In 2017, there were 20,457 pedestrian fatalities in India. Pedestrian crashes have also become a key concern in the state of Tamilnadu, India, due to the high percentage of deaths. If the available datasets are large and complex, identifying key factors is a challenging task. In this study, Multiple Correspondence Analysis (MCA), an exploratory data analysis technique was used to explore the roadway, traffic, crash, and pedestrian-related variables influencing pedestrian crashes. This study used the data from Government of Tamilnadu Road Accident Traffic Management System (RADMS) database, to analyse accident data of nine years (2009–2017) related to pedestrian crashes. The results of the study show that crashes occurring on the express highways on a multilane road are often associated with hit-and-run behaviour among drivers. Factors such as lighting conditions, location, pedestrian behaviour, crossings, and physical separation are also significantly contributing to pedestrian crashes. The key advantage of MCA is that it identifies a possible association between various contributing factors. The findings from this study will be useful for state transport authorities to improve countermeasures for mitigating pedestrian crashes and fatalities.     

Victims of road accidents with serious injuries and dependence on some individual,climatic and infrastructure factors on federal highways in Brazil

Abstract

Road or urban traffic accidents in Brazil have a large presence in external causes of mortality. The main goal of this study is to discover significant factors in the incidence of accidents on Brazilian highways based on a database with information on each person injured on federal highways in Brazil reported by the Federal Highway Police. Some factors are considered in the study as cause of the accident, type of accident, stage of the day, weather condition, highway type, highway facility, age of the victim, gender of the victim and type of vehicle. From the obtained results of chi-square tests and logistic regression models, it was observed statistical dependence (p?<?0.05) of the occurrence of injured people with serious injuries and the factors cause of the accident, type of accident, day, highway type and vehicle type. Considering the dead victims, the covariates age, time of day, highway type, highway facility, gender and type of vehicle showed significance (p?<?0.05). These results are of great interest for authorities to increase road enforcement, improve highway facilities and target the production of vehicles with better safety standards.     

Road traffic crashes at night-time: characteristics and risk factors

Abstract

The study was to examine the nature and risk factors associated with road traffic crashes at night in Ghana and identify potential measures to control them. Crash and injury data for the period 2013-2017 were analyzed. The fatality index and fatal crash ratio measures were employed to assess the severity of injuries among traffic participants. Statistical analysis was carried out for the variables using contingency tables and the chi-square (χ²) tests to assess statistical significance. Generally, night-time traffic crashes resulted in severer injury outcomes than crashes in the hours of daylight (χ²(2)=292.7, p?<?0.001). The relative risk of death in a night traffic crash was 1.3 times that during the daytime. The risk of death was highest among pedestrians (44%) and motorcyclist (18%) compared to bus/mini-bus occupants (16%) and car occupants (11%) and the observed percentage differences were significant (χ²(14)=2303.2, p?<?0.001). Most of the collisions (67%) occurred at the early hours of the night, between 18:00 and 22:00?hours. Poor night visibility coupled with poor visual guidance on roads are the key contributory risk factors associated with night travels. Policies must be geared towards provision of functioning street lights in built-up areas, road line markings, delineators and signage for the highways and arterial roads.     

半速率的建模研究

提出了一种基于二维马氏链的半速率话务模型,从理论上分析并计算了不同话务量时的阻塞概率、半速率承载话务比例及半速率的最佳开启门限.分析表明,随着半速率开启门限和话务量的增大,半速率信道承载话务量比例也将相应增加,从而会影响系统服务质量.文中提出的业务模型和分析方法为实际系统动态调整半速率开启门限提供了理论指导,所得到的不同载波数下、对应不同开启门限的最优话务量范围计算结果也可直接用于实际系统配置.     

Joint pricing and design of urban highways with spatial and user group heterogeneity

This paper addresses the joint optimization of capacity investments and toll charges imposed on multi-group users in monopolistic private highways within general road networks. A game-theoretic formulation is provided that leads to a nonconvex bilevel program. The proposed modeling framework handles several complex issues raised in realistic applications, such as regulations on the levels of tolls and service, and the discrete nature of highway capacity, using a genetic optimization technique. Real-application results show the importance of considering the spatial heterogeneity of prices, and the tradeoff between investments and pricing strategies in regulated private highways.     

A study of factors affecting intersection crash frequencies using random-parameter multivariate zero-inflated models

Recent research demonstrates the appropriateness of multivariate regression models in crash count modelling when one specific type of crash counts needs to be analysed, since they can better handle the correlated issues in multiple crash counts. In this paper, a random-parameter multivariate zero-inflated Poisson (RMZIP) regression model is proposed as an alternative multivariate methodology for jointly modelling crash counts simultaneously. Using this RMZIP model, we are able to account for the heterogeneity due to the unobserved roadway geometric design features and traffic characteristics. Our formulation also has the merit of handling excess zeros in correlated crash counts, a phenomenon that is commonly found in practice. The Bayesian method is employed to estimate the model parameters. We use the proposed modelling framework to predict crash frequencies at urban signalized intersections in Tennessee. To investigate the model performances, three models – a fixed-parameter MZIP model, a random-parameter multivariate negative binomial (RMNB) model, and a random-parameter multivariate zero-inflated negative binomial (RMZINB) model – have been employed as the comparison methods. The comparison results show that the proposed RMZIP models provide a satisfied statistical fit with more variables producing statistically significant parameters. In other word, the RMZIP models have the potential to provide a fuller understanding of how the factors affect crash frequencies on specific roadway intersections. A variety of variables are found to significantly influence the crash frequencies by varying magnitudes. These variables result in random parameters and thereby their effects on crash frequencies are found to vary significantly across the sampled intersections.     

Go small or go home: Operational exposure to violent conflicts and foreign subsidiary exit

This study aims to open the black box of heterogeneous responses to violent conflicts by focusing on subsidiaries’ operational exposure to violent conflict and their decisions to exit host countries. Drawing on real options theory, we propose a viable approach multinational enterprises can take when they encounter violent conflicts in their operating locations. Our analysis of 3,479 foreign subsidiaries operating in 11 countries over 26 years suggests that the exit decision of any given subsidiary located in a conflict-affected country depends on its operational scope. However, this effect depends on the characteristics of the operations the subsidiary undertakes, specifically, whether the subsidiary conducts natural resource-seeking operations and the degree of operational overlap with the same-parent affiliates.     

The Use of Cones to Determine the Market Shares of Service Establishments in a Single Market

This article makes use of the shape of cones to describe the characteristics of market demand at a single location. It then uses the physical properties of cones and their intersections, supported by spacial economic theory, to determine the market shares of service establishments located within a single market. The results not only attach quantitative values to the importance of central place, but also emphasise the flexibility of the model's structure and point to a number of additional uses to which it may be applied. Finally, the model establishes a distance decay function which is based on economic reasoning.     

车联网中交通安全消息动态优先调度机制

车联网中两类交通安全消息共享有限控制信道带宽，在消息突发状态下无法保证事件触发消息的传播性能，导致预警失效。基于差异化的消息传播性能需求提出了一种动态优先级区分的调度机制，按事件优先级分别进行队列管理，赋予事件触发消息优先权，通过设置优先级调度阈值实现对事件触发消息的动态调度。当优先队列长度高于阈值时，其抢占调度时隙。当队列长度低于阈值一半，退出抢占过程，恢复非抢占优先调度方法。仿真显示，所提调度机制能够减小事件触发消息的端到端时延约1.3 ms，提高周期性消息的公平性约0.22。     

Modeling heterogeneous effective advertising stock using single-source data

This paper presents a nonlinear modeling of market response between advertising stock and direct utility with heterogeneous parameters using single-source data. We examine advertising threshold effects and measure the effective advertising stock at the individual consumer level. Two kinds of information, i.e., TV advertising exposure data and consumer’s purchase history data, are combined for the modeling. The former is used for constructing advertising stock over calendar time via heterogeneous carryover parameters and the latter is applied to the choice model. The Markov chain Monte Carlo (MCMC) method is applied to estimate these heterogeneous parameters. Compared to other possible nonlinear specifications, it is shown that the proposed threshold utility function model with discontinuity at the threshold performs better than other smooth market response models. The empirical results support the existence of an advertising threshold and suggest the pulsing or “on/off” policy for our datasets. In terms of the effective reach, implying the reach after suspending the ad exposure to investigate how it is damping out for a possible “on/off” advertising policy, the optimal “off” interval was measured to be quite short to support a high-frequency pulsing policy, because the carryover parameter as well as the difference of ad stock and threshold are not large enough for our datasets.      

Interact with me on my terms: a four segment Facebook engagement framework for marketers

Abstract

Facebook is used by over 1 billion highly heterogeneous users each month. However, there exists little guidance for marketers when it comes to actionable consumer engagement strategies for this social media platform. The purpose of this article is to profile key segments of Facebook users and build an implementable marketing strategy framework that can help marketers better target their Facebook consumers, and better craft their marketing mix and Facebook campaigns. Based on focus group interviews and a qualitative survey, four distinct types of Facebook users are identified and profiled: attention seekers, devotees, connection seekers and entertainment chasers. Correspondingly, a four-segment marketing strategy framework is proposed to guide content creation and engage consumers in thriving Facebook brand communities.     

Social inequalities in injury risk in Wales,U.K.

Road traffic accident data in Nigeria generally lack exact coordinate information. Accident analysis is, therefore, restricted to aggregate data on trends, magnitude and temporal dimensions. This article addresses the road accident problem in Jos between 1995 and 1999 through a road profiling approach. Results show that four gateway routes, seven multilane roadways (including two gateway routes) and seven road intersections accounted for 84% of all traffic accidents, 84% of injured casualties and 88% of fatalities. This approach allows for quantification of impacts of controlling for accidents by deliberate profiling of roads for close monitoring and policing. For example, reducing accident counts and fatalities by 50% each on gateway routes will amount to ～35 and 40% reduction in accident and fatality counts, respectively. Countermeasures must consider these roadways and intersections as important inputs in their accidents and casualty reduction targets.     

Assessment of vehicle speeds on different categories of roadways in Ghana

Empirical evidence from road safety literature suggests that vehicular speed is an important risk factor in the incidence and severity of road traffic crashes globally. Speed studies are at rudimentary stages in developing countries, thus making vehicular speed research imperative. The main aim of the study was to establish two major speed parameters, namely, the mean and dispersion, and their implications for more extensive and long-term speed monitoring in Ghana. Research workers stationed themselves in a parked car and used a radar gun to unobtrusively measure the travelling speeds of 28,489 vehicles at 15 different inter-urban locations on three highway categories. Excessive speeding is very pervasive on all highway categories in Ghana. Travelling speeds through settlements where a speed limit of 50 km/hour is mandatory were particularly excessive. Generally, 98%, 90% and 97% of vehicles exceeded the posted speed limit of 50 km/hour on national, inter-regional and regional roads respectively. Mean speeds and speed dispersions (as assessed by the standard deviations) through built-up areas were 81.3 +/- 17.3 km/hour on national roads, 64.7 +/- 12.3 km/hour on inter-regional roads and 72.6 +/- 13.4, km/hour on regional roads. On rural undivided highways with an 80 km/hour speed limit, mean and speed dispersions were 90 +/- 18.9 km/hour on national roads, 80.1 +/- 16 km/hour on inter-regional roads and 84.4 +/- 15.6 on regional roads; also translating into 66%, 47% and 60% of vehicles exceeding recommended speeds. In all cases, speed dispersions were notably higher than the value of 10 km/hour generally found in developed countries. Excessive speeding and wide speed dispersions are highly prevalent on Ghana's highways. These factors likely account for the high incidence of traffic crashes and fatalities in Ghana. An integrated speed monitoring and control programme and by-passing small and medium settlements would be required for the reduction of speed-related crashes, fatalities and injuries.     

无线交通信号控制系统及新技术的应用

介绍了一种无线交通信号控制系统,该系统是先进的短程无线通信(Zigbee)技术和光耦-固态开关控制技术的有机结合,其性价比高,特别适合应用于没有通信网络的路口、道路和桥梁的交通信号控制.该系统所采用的无线控制技术还可应用于其它方面,如车辆违章图像信息的抓拍和传输.     

Bad behavior and conflict in retailing spaces: Nine suggestions to ease tensions

This article builds on years of work studying territoriality and conflict issues between customers and employees in retail and service settings. The key contribution of this research is to illustrate the bad behaviors and conflicts that take place in retail spaces between customers, between customers and employees, and between employees. Using multi-methods of data collection—critical incident technique, interviews, mystery shoppers, and surveys—the authors outline these bad behaviors and conflicts for managers and offer nine solutions to help retailers handle these behaviors and conflict in retail spaces.     

Infrastrukturgesellschaft Verkehr — Gestaltungs- und Privatisierungsoptionen

The Scientific Advisory Board of the German Federal Ministry of Transport and Digital Infrastructure has commented on draft legislation dealing with the structure of an infrastructure company for federal highways. The Scientific Advisory Board explicitly appreciates institutional reforms of the administration of federal highways but points to several critical design options that have not yet been finalised. Criticism concerns particularly the participation of private investors. Material privatisation of subsidiaries of the infrastructure company should be ruled out in any case.