On the estimation of trip matrices in the case of missing and uncertain data

The problem of missing data in the base (calibration) year is of major importance when applying the gravity model in transportation planning, because base year data are used for calibration of the model. In this article, this problem is tackled by solving an optimization problem for the prediction year for values of the entropy level and the proportions of trips in a given stratification of the cells of the trip matrix estimated in the base year. The problem of uncertain data in the prediction year is handled by replacing equality constraints for the marginal totals in the prediction year by interval constraints. Computational results are given for trip data from the Linköping area.     

Media image of seafarers in the Spanish printed press

This paper presents an analysis of the image of seafarers in Spanish newspapers. This is done by a qualitative and quantitative analysis of the news published in six representative newspapers in the days following the shipwrecks of 24 oil tankers between 1976 and 2007. A total of 359 news items have been studied analysing the type of language used, its place in the pages of the newspapers, the comments of the journalists who wrote them, etc., arriving at the conclusion that seafarers have a bad image in the Spanish printed press.     

Real-time vision-based blind spot warning system: Experiments with motorcycles in daytime/nighttime conditions

This paper describes a real-time vision-based blind spot warning system that has been specially designed for motorcycles detection in both daytime and nighttime conditions. Motorcycles are fast moving and small vehicles that frequently remain unseen to other drivers, mainly in the blind-spot area. In fact, although in recent years the number of fatal accidents has decreased overall, motorcycle accidents have increased by 20%. The risks are primarily linked to the inner characteristics of this mode of travel: motorcycles are fast moving vehicles, light, unstable and fragile. These features make the motorcycle detection problem a difficult but challenging task to be solved from the computer vision point of view. In this paper we present a daytime and nighttime vision-based motorcycle and car detection system in the blind spot area using a single camera installed on the side mirror. On the one hand, daytime vehicle detection is carried out using optical flow features and Support Vector Machine-based (SVM) classification. On the other hand, nighttime vehicle detection is based on head lights detection. The proposed system warns the driver about the presence of vehicles in the blind area, including information about the position and the type of vehicle. Extensive experiments have been carried out in 172 minutes of sequences recorded in real traffic scenarios in both daytime and nighttime conditions, in the context of the Valencia MotoGP Grand Prix 2009.     

Comparison of pedestrian trip generation models

Using Poisson regression and negative binomial regression, this paper presents an empirical comparison of four different regression models for the estimation of pedestrian demand at the regional level and finds the most appropriate model with reference to the National Household Travel Survey (NHTS) 2001 data for the Baltimore (USA) region. The results show that Poisson regression seems to be more appropriate for pedestrian trip generation modeling in terms of χ² ratio test, Pseudo R², and Akaike's information criterion (AIC). However, R² based on deviance residuals and estimated log‐likelihood value at convergence confirmed the empirical studies that negative binomial regression is more appropriate for the over‐dispersed dependent variable than Poisson regression. Copyright © 2011 John Wiley & Sons, Ltd.     

Educating parents to support children’s road safety: a review of the literature

ABSTRACT

This narrative review synthesised the limited work that has been carried out into road safety education targeting parents. Parent education appeared to have a positive impact on child safety seat use and children’s bike helmet use, but results regarding the impact of parent education on pedestrian safety were mixed. The review highlighted important gaps in the literature. A key gap being identifying effective ways to engage parents of low socioeconomic and ethnic minority backgrounds. Further, another gap is understanding effective ways to engage and support parents of children with additional needs to build their children’s road safety skills. There is some evidence that parent education has a positive impact on these “at-risk” groups, but little work on how to engage with these groups and the type of parent education required.     

An exploration of shoppers travel mode choice in visiting convenience stores in the UK

Using data from over 2000 convenience store customers within and outside London, this paper explores how individuals access their convenience stores and how significant the influence of their socio-demographics, shopping types and trip chaining is to their mode choice in visiting the stores. Trip chaining is found to be crucial in influencing customers' mode choice and their visit frequency. The application of logit models also shows that frequent shoppers are the ones most likely to visit the stores on foot. Interestingly, the estimation results also show that the location's density, shopping types and the day of the week are not significant in influencing travel modes. Customers who live in the most deprived areas are less likely to use a private car in visiting the stores.     

Segmentation of paratransit users based on service quality and travel behaviour in Bandung,Indonesia

Using a data-set collected among paratransit users in Bandung, Indonesia, this paper explores the impacts of paratransit users' negative experiences and dissatisfactions with their paratransit usage pattern. Segmentation and ordered probit analyses are used to examine the impacts of users' opinions on service quality on their trip-making behaviour. The results indicate that users are divided into six segments – namely, the unlucky, the young user, the experienced, the adapter, the infrequent user and the captive. The results further indicate that paratransit users, especially women, perceive negative experiences related to on-time performance (departure and arrival time) and security issues related to vehicles. Despite these dissatisfactions and negative experiences, they are still likely to use paratransit as part of their daily life. Two paratransit market segments (the adapter and the captive) are also likely to result in more trips using paratransit. The study offers several strategies and recommendations that can improve the current paratransit system so that it can better serve local needs.     

Influence of nozzle hole diameter and orifice diameter on dme spray to get the similar heat value with diesel spray using the constant volume chamber

Low heating value (LHV) of di-methyl ether (DME) is lower than that of diesel. To get the similar heat value with diesel from the diesel engine operation, single injection quantity of DME should be increased. This investigation was tried to increase the injection quantity of DME by the modified diesel injector and investigated the penetration length and spray angle of DME spray. DME was injected by using three-type modified diesel injectors those nozzle-hole diameters (Injector 1: 1.66 mm, Injector 2 and 3: 0.25 mm) and orifice diameters were different (Injector 1 and 2: 0.6 mm, Injector 3: 1 mm). Spray characteristics of DME was investigated with a various ambient pressures (2.5, 5.0 MPa) in the constant volume chamber and a fuel was injected by varied injection pressure from 35 to 70 MPa by interval of 5 MPa using a DME common rail fuel injection system. The result shows that DME injection quantity by Injector 3 was 1.69 ~ 2.02 times larger than that of diesel injection quantity by Injector 1. In this case, DME spray got the similar heat value compared with diesel spray. The penetration speed of DME spray by Injector 3 was the fastest, thus when the spray development was end, the penetration length of DME spray by Injector 3 was the longest compared with the other cases. In case of the spray angle, Injector 2 and 3 had the similar spray angle and these were larger than that of diesel and DME sprays by Injector 1. As the result, Injector 3 was the solution for how to solve the low heating value of DME.     

Classification of Beach Erosion Vulnerability on the Yucatan Coast

Beach erosion can have important socioeconomic and environmental consequences, particularly in tropical regions where tourism is a significant source of income. Although caused by natural processes, erosion is often aggravated by disorderly anthropogenic modification of the coast and extreme events. In Yucatan, Mexico, increasing urban development and deficient coastal management strategies as well as hurricanes have affected beach stability. This has highlighted the need for adequate coastal planning and policies that ensure the protection of key coastal ecosystems, such as beaches and sand dunes. To address this, a methodology to classify the coast according to its vulnerability is presented in this work. This methodology assumes that morphological features are indicators of beach evolution and the processes driving it and that these can be associated with different levels of vulnerability. The features considered are beach width, dune vegetation, anthropogenic pressure, and shoreline orientation, which were analyzed through aerial images and a multicriteria evaluation. It was observed that the most vulnerable areas are found near the most developed parts of the coast, where narrow beaches with little dune vegetation dominate. It is expected that this index will be of use to coastal planners and decision makers, particularly in the identification of critical zones.