Sharif Digital Repository

Nowadays, with population growth and vehicle traffic increase, only providing transportation supply couldn’t answer the transportation demand. One of the most important solutions to reduce traffic is transportation demand management (TDM). In this research, the effects of parking pricing and improving public transportation services on private car demand reduction in city center are examined. The data are collected from private cars users in the city center of Isfahan through interviews. By stated preference method, the impacts of parking price and public transit travel time and other related factors were investigated. For this purpose, binary logit, multinomial logit and nested logit models... 

This study examines four models of the individual’s preference for home- and center-based telecommuting. Issues concerning the estimation of discrete models when the alternatives are non-exclusive are discussed. Two binary logit models are presented, one on the preference to telecommute from a center versus not telecommuting from a center, and the other on the preference to telecommute from a center over telecommuting from home. A model is also estimated on the following four alternatives: preferring not to telecommute, preferring either form of telecommuting, preferring to telecommute from home, and preferring to telecommute from a center. A comprehensive model of two distinct dimensions of... 

Integration of transportation demand management (TDM) policies, as a realistic and effective approach, is a challenging issue in urban policy studies. This study examines the role of transportation demand management (TDM) policy packages on commuters' mode choice in the city of Tehran. The analysis is based on the results of stated preferences survey developed by efficient choice design as a specialized type of fractional factorial design approach. Five policies, namely increasing parking cost, increasing fuel cost, cordon pricing, transit time reduction and transit access improvement, are assessed in considering six modes of travel to work place. A multinomial logit model has been developed... 

Evaluation of the effects of vehicle characteristics on accident severity is the main objective of this research. In addition to some static and dynamic features of passenger cars, some characteristics of driver and roadway are studied, too. In this research, driver injury severity is modeled as accident severity index. First, the severity of head-on, rear-end, angle and sideswipe accidents are modeled using Binary Logit models. Then, Multinomial Logit models are applied to develop driver injury severity models for head-on and rollover accidents. Finally, Nested Logit model is developed to model severity of head-on accidents to study the performance of different types of Logit models.... 

Improvement of public transportation systems through attention to service quality of these systems, is important in order to increase the use of these systems. Various quantitative and qualitative attributes of travel are known effective on service quality of public transportation. The investigated factors in this research, with refrence to regular bus system of the city of Tehran, are: in-vehicle time, fare, crowding and headway. For this purpose, the stated preference data of the respondents who travel to work by regular bus, collected. The survey was conducted during the last month of spring and 360 questionnaires were completed. Stated preference scenarios relating to aforementioned... 

Trip demand analysis is among the most important parts in comprehensive transportation studies. Developing four stage models including trip generation, trip distribution, mode choice, and assignment are so common in demand analyzing. In this study, trip generation models have been studied and to analyze data, two different methods including OLR and GWR are utilized. This study aims to examine relationship between aggregate zones in order to forecast future trips. Moreover, results of modeling trip generation with two different methods, OLR and GWR, are compared. Comparing different levels of aggregation reveals that as the number of zones decreases, the results get better. Decreasing number... 

One of the most important criteria in travel analysis is the vehicle kilometer traveled (VKT). The distance which personal cars, vans or other automobiles travel is measured through this criterion. In addition, the VKT is used in transportation planning, accident analysis, transportation budgets assignment, and estimation of automobile pollutions. In this work we process origin-destination data gathered in Shiraz, Iran to estimate the VKT. To this end, we incorporate the linear regression and geographically weighted regression (GWR) methods. Through this research, data from origin-destination statistics of Shiraz, gathered by the transportation institute of Sharif University of Technology in... 

Since expansion of communication technology, telecommuting has gained attention from transportation planners as an approach in field of demand management. In this research, joint effects of feasibility of telecommuting for the employees of each organization and the relevant frequency of employees have been evaluated by using the copula model as the most recent conventional way of developing a joint model since the last few years. The result of telecommuting acceptance is that after presenting the project to each organization, the head employer measures the appropriateness of the project for employees and if he reaches a consensus on the success of the project, the employees get involved and... 

The relationship between travel behavior and Built Environment has been context of variety of research during past decades. Many modern urban development theories such as new-urbanism and smart growth are commonly based on interactions between these two concepts. This research is aiming to analyze the effects of built environment on household trip generation, mode and destination choice as specific indices of travel behavior, based on travel diary data of Shiraz city. Multiple Linear Regression and Multinomial Logit Model concepts are used to analyze aforementioned travel behaviors in two levels. Base models predict socio-economic variables importance and expanded models are used to test... 

Nearly 1.2 million people die in road crashes each year, and as many as 50 million are injured in the world. In Iran, approximately 800 thousand crashes occur annually killing up to 43 people per day. Given that over 90% of accidents are related to human factors, using models that incorporate driver’s attitudes and behavior can be highly predictive of crashes. The main objective of the current research is to examine the impact of drivers’ attitudes on road crashes along with other factors such as socio-demographic characteristics and vehicle type. This study uses data from a self-completed questionnaire among a representative sample of Iranian drivers living in Tehran. The Questionnaire... 

Like any other Information Communication Technology (ICT) solution, E-shopping alters shopping trip patterns in a city. Product internet searching is another ICT solution which affects shopping trip patterns in a city. At the first stage, by producing ordinal regression models, this study explores all factors which are effective in adoption and frequency of product internet searching and e-shopping. In the next step, rather than pre-imposing restrictive assumptions regarding dependence, this study determines the structure of dependency between product internet searching and e-shopping with two (adoption and frequency) joint models by implementing the copula-based approach. This study relies... 

There is a specific focus in sustainable transportation to three domains of safety, air pollution, and energy consumption. All these three domains are affected by the vehicle type choice. An important factor to estimate the impact of vehicle type choice on safety, air pollution, and the energy consumption is self-selection, defined as the tendency of people to make their travel-related choices based on their abilities, needs, and preferences. Ignoring the self-selection effect may cause a bias in the estimation of the coefficients of affecting variables on the travel-related choice. The main objective of this thesis is to study the self-selection effect in vehicle type choice considering the... 

Different definitions of the term ‘subjective well-being’ have been defined by different researchers. While there is no definite definition for this concept, it can be related to one's life evaluation. The issue of citizens’ subjective well-being has not usually been considered in transportation policies, such as reducing single occupancy vehicle. However, subjective well-being reflects the individuals’ quality of life and can be one of the main priorities of any society. This study tries to find the effect of using various modes of travel including passenger car, motorcycle, public transportation and walking on citizens' subjective well-being. Subjective well-being is measured by... 

Crash severity is among the fundamental safety indicators in transportation. In recent years, distracted driving has been one of the biggest concerns in road crashes. Many scholars have evaluated the effects of distraction in crash severities and injuries. This study uses the latest general estimates system (GES) crash dataset, which is a subset of the US National Automotive Sampling System (NASS) and the structural equation model (SEM) approach to explore the relationships between distraction factors and crash severity in male and female drivers. Using SEM for modeling about 22 thousand observations offers the opportunity to simultaneously examine complex relationships between variables by... 

In recent years, a number of studies have focused on investigating the relationship between vehicle type choice and usage. A comprehensive understanding of the factors influencing this topic can be extremely beneficial in transportation and urban studies, as well as future policymaking. In this study, the relationship between vehicle type choice and usage is investigated in the context of the city of Tehran. To provide a better understanding of the corresponding socio-economic variables, each of the decisions regarding vehicle type choice and usage in this relationship is viewed as an interrelated dimension of a single choice package rather than two independent choices. The primary data set... 

Today, accidents are considered as one of the main causes of human mortality in the world. According to the World Health Organization, about 1.35 million people die in accidents each year, and 20 to 50 million people are injured because of accidents. In our country, about 17000 people are killed in traffic accidents annually. The mentioned statistics clarify the significance of paying attention to traffic accidents and identifying the factors that lead to them, as well as considering the strategies and policies for reducing accident rates. Due to the fundamental role of human factors in the occurrence of car accidents, the use of models that include the personality and attitude of drivers... 

The object of this investigation is to explore women employees' preferences toward telecommuting. As the increasing role of women in social and economical activities expands their contributions to urban traffic and the importance of Transportation Demand Management (TDM) including telecommuting, which is a new strategy in management and modification of commuting pattern, needs to be addressed. The sample used in this research has obtained from the questionnaire distributed at seven governmental and semi-governmental organizations. The data is used to generate models which are applied to examine women telecommuting preferences, and their preferences from home or local offices. The amount of... 

Although car ownership models are not one of the four steps of the classical travel demand modeling, an external car ownership model or an internal car ownership sub-model is used in many transport model systems, as an input to mode choice and sometimes also to trip generation and distribution. Utilizing data of Tehran's transportation master plan conducted in 2004, this study develops models for estimating private car ownership with aggregate data (at zonal level) and disaggregate data (at household level) and inspects factors influencing car ownership at both levels. In aggregate modeling, methods of linear regression, geographically weighted regression (GWR) and Quarmby and Bates are used... 

Motorcycles are very dangerous as safety point of view and their drivers are more than other vehicles' drivers subject to danger. In recent years, death rate of motorcycles accidents in Iran is increased as much as it has become the government's concern. The purpose of this research is the analysis of the effects of various factors in the intensity of the motorcycles accidents in the national rural roads. In order to do this, the information of the rural motorcycles accidents that are happened in 2010 and the spring of 2011 is used. Explanatory variables are categorized to various factors like perimeter characteristics, driver's characteristics, crash characteristics and the roads... 

Inadequate accuracy of four-step demand models, conducted researchers to use the activity-based models. Decisions such as activity type choice and its duration, play a key role in these models as ingredients. On mentioned cases, deciding process is not in order, but is simultaneous. Existence of biases such as Selectivity, is a motivation to use joint models which include a wide spectrum. Due to lacking closed form for most of these models, researchers often confront to some difficulties. Looking for solution for the difficulties, lighten the idea of using Copula transforms to propose joint models. Enjoying Copulas, a closed form for joint models is achievable. Also, a wide range of...