Gil Tal - Academia.edu (original) (raw)

Papers by Gil Tal

Transportation Research Record: Journal of the Transportation Research Board, 2008

ABSTRACT Overestimated forecasts or the impacts or new policies, that is, over-prediction of the ... more ABSTRACT Overestimated forecasts or the impacts or new policies, that is, over-prediction of the successes of the policies, are a well-known problem. Study of the effects of forecasting methods on potential bias may help modelers, planners, and policy makers better use forecasting tools. This paper addresses the overestimation of the success of telecommuting as a travel demand management policy. The research hypothesis underlying this study posits that overestimates of performance are virtually inevitable when the effects of new policies that aim to change travel behavior are forecast but that these biases eventually decline over time. The sources of overestimated forecasts are the prediction tools used and the ways in which modelers use these tools. The sources of the reduction in overestimation are the changes made to these tools and the knowledge and the data gained over time.

Carsharing in the United States has been a focus of study and research for more then a decade. It... more Carsharing in the United States has been a focus of study and research for more then a decade. Its proponents argue that carshare adoption will reduce VMT in cities and can serve as a travel demand management policy. However, no comprehensive forecasting of carsharing impact has been done and most of the evidence is based on evaluation studies of new carshare projects. This paper focuses on the gap between the available data and knowledge and the required data and knowledge. The study demonstrates how the data and knowledge gap contributes to optimism bias about the expected impact of carsharing as a TDM policy. 3

Overestimated forecasts of the impact of new policy, which over-predict policy success, are a wel... more Overestimated forecasts of the impact of new policy, which over-predict policy success, are a well-known problem. Studying the effects of forecasting methods on potential biases may help modelers, planners and policy makers better use the forecasting tools. This paper addresses overestimation of telecommuting as a travel demand management (TDM) policy. The research hypothesis underlying this study posits that overestimates are virtually inevitable in forecasting the effect of new policies that aim to change travel behavior, but these biases eventually decline over time. The sources of overestimated forecast are the prediction tools used, and the ways in which modelers use these tools. The sources of the reduction in overestimation are the changes made to the modeling tools results from knowledge and data gained over time.

2013 World Electric Vehicle Symposium and Exhibition (EVS27), 2013

In recent years, transportation planners have devoted more attention to the goal of increasing th... more In recent years, transportation planners have devoted more attention to the goal of increasing the non-motorized trips of children and adults. Non-motorized trips are considered important as a mean of reducing motorized trips as well increasing physical activity. Indeed, lack of physical activity has been identified as a major public health problem for both adults and younger people (Center of Disease control (CDC), 2005; Sallis, et al., 2004). A CDC report from 2002, for example, reports that about a third of the teenagers are not physically active enough (CDC, 2002). The lack of physical activity among children is, in part, associated with travel behavior and urban form (Ewing et al, 2003, Handy et al, 2002; Martin-Diener et al, 2005): children living in auto-oriented areas in the U.S. use walking and biking as modes of transportation to nearby destinations to a limited extent and less than in the past (Sallis et al, 1993; Sallis et al 2000). Their high level of auto use is, of co...

Transportation Research Record: Journal of the Transportation Research Board, 2014

The growing plug-in electric vehicle (PEVs) market features new models of battery electric vehicl... more The growing plug-in electric vehicle (PEVs) market features new models of battery electric vehicles (BEVs) and Plug-in hybrid vehicles (PHEVs) with varying battery sizes and electric driving range. How are these different models being used in the real world? A common assumption in PEV impact analysis is that PEV owners will maximize their vehicle utility by appropriately sizing their battery to their driving needs and by charging their vehicles as much as possible to recover the cost of the vehicle purchase. Based on these assumptions we expect a high correlation between PHEV owners usage of the vehicle and the number of plug-in events, and we expect drivers of PHEVs with small battery to plug in more than owners of vehicles with a larger battery and similar driving patterns. This paper examines the assumptions presented using a survey of more than 3,500 PEV owners conducted in California from May and June 2013. The online survey includes extensive data on driving and charging behavior using web-map questions and includes owners of all PEV models in the market including more than 600 Volts and 800 Plug-in Priuses. The results show that small battery PHEV electric vehicle miles traveled (eVMT) are lower than larger range PHEV or BEVs not only because of the battery size but also as a result of the public charging availability and charging behavior. Higher electric range PHEV and BEV drivers charge more often and report more charging opportunities in the same areas that smaller battery PHEVs could not find chargers.

Transportation Research Record: Journal of the Transportation Research Board, 2012

ABSTRACT This paper explores measures of pedestrian accessibility and network connectivity with a... more ABSTRACT This paper explores measures of pedestrian accessibility and network connectivity with a network that includes pedestrian facilities in addition to the street network. Studies that focus on walkability usually use available street networks that do not include pedestrian-only facilities. The effect of missing pedestrian connections where the street network is richer than the pedestrian network has been examined in some studies, but the case of suburban environments with robust pedestrian networks has mostly been ignored. In the current study, various measures of connectivity and accessibility were compared between the pedestrian network and the street network in different suburban settings and for accessibility to different land use activities, such as schools and retail centers. Documenting the degree to which the pedestrian network enhanced pedestrian accessibility over the street network alone was motivated by the desire to inform research and to inform policy. Nine neighborhoods in the city of Davis, California, with typical suburban densities, a variety of street network types, and an extensive system of off-street bicycle and pedestrian facilities were used in the study. A network that included all minor and primary roads in the city plus pedestrian ways was also used. This network included 60 mi of off-street facilities and excluded freeways not open to pedestrians. Households were used as origins and schools and retail centers as destinations to demonstrate the effect of the pedestrian network on connectivity and accessibility in different parts of the city. The results of this study can be used to improve the measurement of built environment in studies of active travel and to increase understanding of the effect of the pedestrian network in the suburban environment.

2013 World Electric Vehicle Symposium and Exhibition (EVS27), 2013

Who is buying electric vehicles? Who is buying new cars in general? Is the first group a subset o... more Who is buying electric vehicles? Who is buying new cars in general? Is the first group a subset of the second? What are the similarities and differences of the two groups? Can we use hybrid buyers to predict the future plug-in electric vehicle (PEV) market? This study explores the characteristics of new car buyer households who purchased a new vehicle in California during 2011-2012 comparing three main populations: internal combustion engine (ICE) buyers, hybrid buyers and PEV buyers. We show that PEV households have different socio-demographic characteristics than ICE buyers with, for example, higher income, higher education, and more new cars while hybrid owners are a middle group with characteristics that fall between those of ICE and PEV owners. We also found differences among PEV buyers. Pure battery electric vehicle (BEV) and plug-in hybrid electric (PHEV) households have similar sociodemographic characteristics but they are differentiated by driving characteristics and home location. The PEV market today is based on small number of buyers and small number of potential new car buyers.

Allowing single-occupant advanced clean vehicles to use carpool or high occupancy vehicle (HOV) l... more Allowing single-occupant advanced clean vehicles to use carpool or high occupancy vehicle (HOV) lanes is an important non-monetary sales incentive. This incentive needs to be balanced against the potential cost of increased congestion on those lanes and reduced revenue of high occupancy toll (HOT) lanes, especially during peak travel periods. In a 2013 survey, when Plug-In in vehicle buyers were asked about their primary motivation to buy a plug in car, 57% of Plug-in Priuses, 34% of Volts and 38% of LEAFs identified the HOV sticker. Current legislation in California allows a limited number of stickers for plugin hybrid vehicles and an unlimited number for full battery electric vehicles. This paper offers an analysis on the impact of these stickers on the vehicle purchase decision and the resulting electric miles traveled. We also offer an analysis of the potential cost in terms of miles driven on HOV lanes. The results can help policy makers optimize the benefit for each additional permit while understanding the impact of different vehicle types.

The SAGE Handbook of Transport Studies, 2013

This chapter explores the impacts of information and communications technology (ICT) on trip/acti... more This chapter explores the impacts of information and communications technology (ICT) on trip/activity generation, destination, mode, and route choice, execution time and duration, and automobile ownership. The complexity of the relationships involved derives from the multiple roles of ICT. In the pre-trip phase it serves as inspiration, information provider, decision variable, and one of the alternatives itself. Post-departure, it can change the chosen alternative, and alter the trip experience. Accordingly, a net outcome of travel substitution or (more often) complementarity generally represents the combined effects of multiple impacts operating in multiple directions. Gaps in knowledge and overarching trends and issues are highlighted.

Transportation Research Record: Journal of the Transportation Research Board, 2008

ABSTRACT Overestimated forecasts or the impacts or new policies, that is, over-prediction of the ... more ABSTRACT Overestimated forecasts or the impacts or new policies, that is, over-prediction of the successes of the policies, are a well-known problem. Study of the effects of forecasting methods on potential bias may help modelers, planners, and policy makers better use forecasting tools. This paper addresses the overestimation of the success of telecommuting as a travel demand management policy. The research hypothesis underlying this study posits that overestimates of performance are virtually inevitable when the effects of new policies that aim to change travel behavior are forecast but that these biases eventually decline over time. The sources of overestimated forecasts are the prediction tools used and the ways in which modelers use these tools. The sources of the reduction in overestimation are the changes made to these tools and the knowledge and the data gained over time.

Carsharing in the United States has been a focus of study and research for more then a decade. It... more Carsharing in the United States has been a focus of study and research for more then a decade. Its proponents argue that carshare adoption will reduce VMT in cities and can serve as a travel demand management policy. However, no comprehensive forecasting of carsharing impact has been done and most of the evidence is based on evaluation studies of new carshare projects. This paper focuses on the gap between the available data and knowledge and the required data and knowledge. The study demonstrates how the data and knowledge gap contributes to optimism bias about the expected impact of carsharing as a TDM policy. 3

Overestimated forecasts of the impact of new policy, which over-predict policy success, are a wel... more Overestimated forecasts of the impact of new policy, which over-predict policy success, are a well-known problem. Studying the effects of forecasting methods on potential biases may help modelers, planners and policy makers better use the forecasting tools. This paper addresses overestimation of telecommuting as a travel demand management (TDM) policy. The research hypothesis underlying this study posits that overestimates are virtually inevitable in forecasting the effect of new policies that aim to change travel behavior, but these biases eventually decline over time. The sources of overestimated forecast are the prediction tools used, and the ways in which modelers use these tools. The sources of the reduction in overestimation are the changes made to the modeling tools results from knowledge and data gained over time.

2013 World Electric Vehicle Symposium and Exhibition (EVS27), 2013

In recent years, transportation planners have devoted more attention to the goal of increasing th... more In recent years, transportation planners have devoted more attention to the goal of increasing the non-motorized trips of children and adults. Non-motorized trips are considered important as a mean of reducing motorized trips as well increasing physical activity. Indeed, lack of physical activity has been identified as a major public health problem for both adults and younger people (Center of Disease control (CDC), 2005; Sallis, et al., 2004). A CDC report from 2002, for example, reports that about a third of the teenagers are not physically active enough (CDC, 2002). The lack of physical activity among children is, in part, associated with travel behavior and urban form (Ewing et al, 2003, Handy et al, 2002; Martin-Diener et al, 2005): children living in auto-oriented areas in the U.S. use walking and biking as modes of transportation to nearby destinations to a limited extent and less than in the past (Sallis et al, 1993; Sallis et al 2000). Their high level of auto use is, of co...

Transportation Research Record: Journal of the Transportation Research Board, 2014

The growing plug-in electric vehicle (PEVs) market features new models of battery electric vehicl... more The growing plug-in electric vehicle (PEVs) market features new models of battery electric vehicles (BEVs) and Plug-in hybrid vehicles (PHEVs) with varying battery sizes and electric driving range. How are these different models being used in the real world? A common assumption in PEV impact analysis is that PEV owners will maximize their vehicle utility by appropriately sizing their battery to their driving needs and by charging their vehicles as much as possible to recover the cost of the vehicle purchase. Based on these assumptions we expect a high correlation between PHEV owners usage of the vehicle and the number of plug-in events, and we expect drivers of PHEVs with small battery to plug in more than owners of vehicles with a larger battery and similar driving patterns. This paper examines the assumptions presented using a survey of more than 3,500 PEV owners conducted in California from May and June 2013. The online survey includes extensive data on driving and charging behavior using web-map questions and includes owners of all PEV models in the market including more than 600 Volts and 800 Plug-in Priuses. The results show that small battery PHEV electric vehicle miles traveled (eVMT) are lower than larger range PHEV or BEVs not only because of the battery size but also as a result of the public charging availability and charging behavior. Higher electric range PHEV and BEV drivers charge more often and report more charging opportunities in the same areas that smaller battery PHEVs could not find chargers.

Transportation Research Record: Journal of the Transportation Research Board, 2012

ABSTRACT This paper explores measures of pedestrian accessibility and network connectivity with a... more ABSTRACT This paper explores measures of pedestrian accessibility and network connectivity with a network that includes pedestrian facilities in addition to the street network. Studies that focus on walkability usually use available street networks that do not include pedestrian-only facilities. The effect of missing pedestrian connections where the street network is richer than the pedestrian network has been examined in some studies, but the case of suburban environments with robust pedestrian networks has mostly been ignored. In the current study, various measures of connectivity and accessibility were compared between the pedestrian network and the street network in different suburban settings and for accessibility to different land use activities, such as schools and retail centers. Documenting the degree to which the pedestrian network enhanced pedestrian accessibility over the street network alone was motivated by the desire to inform research and to inform policy. Nine neighborhoods in the city of Davis, California, with typical suburban densities, a variety of street network types, and an extensive system of off-street bicycle and pedestrian facilities were used in the study. A network that included all minor and primary roads in the city plus pedestrian ways was also used. This network included 60 mi of off-street facilities and excluded freeways not open to pedestrians. Households were used as origins and schools and retail centers as destinations to demonstrate the effect of the pedestrian network on connectivity and accessibility in different parts of the city. The results of this study can be used to improve the measurement of built environment in studies of active travel and to increase understanding of the effect of the pedestrian network in the suburban environment.

2013 World Electric Vehicle Symposium and Exhibition (EVS27), 2013

Who is buying electric vehicles? Who is buying new cars in general? Is the first group a subset o... more Who is buying electric vehicles? Who is buying new cars in general? Is the first group a subset of the second? What are the similarities and differences of the two groups? Can we use hybrid buyers to predict the future plug-in electric vehicle (PEV) market? This study explores the characteristics of new car buyer households who purchased a new vehicle in California during 2011-2012 comparing three main populations: internal combustion engine (ICE) buyers, hybrid buyers and PEV buyers. We show that PEV households have different socio-demographic characteristics than ICE buyers with, for example, higher income, higher education, and more new cars while hybrid owners are a middle group with characteristics that fall between those of ICE and PEV owners. We also found differences among PEV buyers. Pure battery electric vehicle (BEV) and plug-in hybrid electric (PHEV) households have similar sociodemographic characteristics but they are differentiated by driving characteristics and home location. The PEV market today is based on small number of buyers and small number of potential new car buyers.

Allowing single-occupant advanced clean vehicles to use carpool or high occupancy vehicle (HOV) l... more Allowing single-occupant advanced clean vehicles to use carpool or high occupancy vehicle (HOV) lanes is an important non-monetary sales incentive. This incentive needs to be balanced against the potential cost of increased congestion on those lanes and reduced revenue of high occupancy toll (HOT) lanes, especially during peak travel periods. In a 2013 survey, when Plug-In in vehicle buyers were asked about their primary motivation to buy a plug in car, 57% of Plug-in Priuses, 34% of Volts and 38% of LEAFs identified the HOV sticker. Current legislation in California allows a limited number of stickers for plugin hybrid vehicles and an unlimited number for full battery electric vehicles. This paper offers an analysis on the impact of these stickers on the vehicle purchase decision and the resulting electric miles traveled. We also offer an analysis of the potential cost in terms of miles driven on HOV lanes. The results can help policy makers optimize the benefit for each additional permit while understanding the impact of different vehicle types.

The SAGE Handbook of Transport Studies, 2013

This chapter explores the impacts of information and communications technology (ICT) on trip/acti... more This chapter explores the impacts of information and communications technology (ICT) on trip/activity generation, destination, mode, and route choice, execution time and duration, and automobile ownership. The complexity of the relationships involved derives from the multiple roles of ICT. In the pre-trip phase it serves as inspiration, information provider, decision variable, and one of the alternatives itself. Post-departure, it can change the chosen alternative, and alter the trip experience. Accordingly, a net outcome of travel substitution or (more often) complementarity generally represents the combined effects of multiple impacts operating in multiple directions. Gaps in knowledge and overarching trends and issues are highlighted.