Vol 18 No 2 (2018)
2018-04-01
Vol 18 No 2 (2018)
2018-04-01
Articles
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In urban areas and especially in inner cities, pedestrians crossing the road considerably influence the road traffic flow. For political reasons, priority could be given to pedestrians. A larger number of crossings reduces the pedestrian load per crossing and facilitates both the pedestrian flow and the car flow; the ultimate case is a “cross anywhere” scenario. Earlier work shows that the road capacity decreases with the square of the pedestrian crossing time, hence a short crossing time is desired. Crosswalks can ensure pedestrians cross orthogonally, and thus quickly, and can thereby improve traffic flow. Moreover, a limited number of crosswalks is less stressful than a “cross anywhere” scenario for a car driver since (s)he only needs to expect crossing pedestrians at dedicated crosswalks. This paper studies the effect of the distances between crosswalk and road traffic capacity. The paper’s goal is finding a single formula or universal set of charts that can describe the effect of pedestrian crosswalks on traffic flow under virtually all scenarios (with long blocks). This type of result would obviate the need for simulations of specific situations when only a rough assessment of the effect of crosswalks is desired. Traffic flow for several distances between pedestrian crossings is simulated, and moreover, a non-constant inter-crosswalk spacing is considered. The simulation results can be used for other situations, using transformations and an interpolation recipe. Overall, the closer the crosswalks, the better the flow. However, spacings closer than approximately 25-50 meters do not add much. Speed of traffic under a broad array of pedestrian crossing scenarios is given.
In urban areas and especially in inner cities, pedestrians crossing the road considerably influence the road traffic flow. For political reasons, priority could be given to pedestrians. A larger number of crossings reduces the pedestrian load per crossing and facilitates both the pedestrian flow and the car flow; the ultimate case is a “cross anywhere” scenario. Earlier work shows that the road capacity decreases with the square of the pedestrian crossing time, hence a short crossing time is desired. Crosswalks can ensure pedestrians cross orthogonally, and thus quickly, and can thereby improve traffic flow. Moreover, a limited number of crosswalks is less stressful than a “cross anywhere” scenario for a car driver since (s)he only needs to expect crossing pedestrians at dedicated crosswalks. This paper studies the effect of the distances between crosswalk and road traffic capacity. The paper’s goal is finding a single formula or universal set of charts that can...
In urban areas and especially in inner cities, pedestrians crossing the road considerably influence the road traffic flow. For political reasons, priority could be given to pedestrians. A larger number of crossings reduces the pedestrian load per crossing and facilitates both the pedestrian...
Victor L. Knoop, Carlos F. Daganzo -
This paper considers bicycle route choice for commuter trips. Bicycle route preferences are analysed using a dataset from a GPS-assisted household travel survey conducted in the Tel Aviv metropolitan area. Different choice set generation methods were applied to generate alternative routes for each observation, and the matching with the actual route is discussed. Model estimation is performed for different route choice sets to test the sensitivity of the parameter estimates. The results obtained are quite consistent, and indicate an expected tendency to ride in longer routes, but with separated bike lanes. In the absence of such lanes, riders prefer to use local streets and avoid riding on busy arterial streets and highways.
This paper considers bicycle route choice for commuter trips. Bicycle route preferences are analysed using a dataset from a GPS-assisted household travel survey conducted in the Tel Aviv metropolitan area. Different choice set generation methods were applied to generate alternative routes for each observation, and the matching with the actual route is discussed. Model estimation is performed for different route choice sets to test the sensitivity of the parameter estimates. The results obtained are quite consistent, and indicate an expected tendency to ride in longer routes, but with separated bike lanes. In the absence of such lanes, riders prefer to use local streets and avoid riding on busy arterial streets and highways.
This paper considers bicycle route choice for commuter trips. Bicycle route preferences are analysed using a dataset from a GPS-assisted household travel survey conducted in the Tel Aviv metropolitan area. Different choice set generation methods were applied to generate alternative routes for...
Muhammad Ghanayim, Shlomo Bekhor -
This paper studies clusters in the logistics sector. Like traditional cluster research, indicators of concentration to detect co-location of employment are calculated. However, this approach is enhanced by including a quantitative analysis of the inter-firm relations between logistics companies through the use of a community detection algorithm on a microeconomic dataset of buyer-supplier relations. Combining both results in a typology of logistics clusters. Next to the big clusters characterized by employment concentration and many internal and external relations, spill-over and polycentric clusters are identified. This approach seems promising to detect in future research clusters in other sectors and places
This paper studies clusters in the logistics sector. Like traditional cluster research, indicators of concentration to detect co-location of employment are calculated. However, this approach is enhanced by including a quantitative analysis of the inter-firm relations between logistics companies through the use of a community detection algorithm on a microeconomic dataset of buyer-supplier relations. Combining both results in a typology of logistics clusters. Next to the big clusters characterized by employment concentration and many internal and external relations, spill-over and polycentric clusters are identified. This approach seems promising to detect in future research clusters in other sectors and places
This paper studies clusters in the logistics sector. Like traditional cluster research, indicators of concentration to detect co-location of employment are calculated. However, this approach is enhanced by including a quantitative analysis of the inter-firm relations between logistics...
Joris Beckers, Isabelle Thomas, Thomas Vanoutrive, Ann Verhetsel -
Transportation network companies commonly enter the market for taxi ride intermediation and alter the market outcome. Compared to cooperatively organized radio-taxi dispatch service agencies, transportation network companies run larger fleets and serve more customers with lower fares, when the fixed costs of the dispatch office are relatively small. The same holds for private dispatch firms, when the fixed costs of a taxicab are not too small. These results are shown in a two-stage duopoly of fare and fleet size competition with fare- and waiting-timedependent demand.
Transportation network companies commonly enter the market for taxi ride intermediation and alter the market outcome. Compared to cooperatively organized radio-taxi dispatch service agencies, transportation network companies run larger fleets and serve more customers with lower fares, when the fixed costs of the dispatch office are relatively small. The same holds for private dispatch firms, when the fixed costs of a taxicab are not too small. These results are shown in a two-stage duopoly of fare and fleet size competition with fare- and waiting-timedependent demand.
Transportation network companies commonly enter the market for taxi ride intermediation and alter the market outcome. Compared to cooperatively organized radio-taxi dispatch service agencies, transportation network companies run larger fleets and serve more customers with lower fares, when the...
Thorsten Heilker, Gernot Sieg -
This paper examines the efficiency of international airlines for the period 1998-2012 using some competing stochastic frontier (SF) panel data models. It estimates a cost function for multi-output airline services, separating passenger and goods transportation at the national and international levels. Our preferred SF model distinguishes airlines heterogeneity from time-invariant persistent inefficiency, and transient (time-varying) inefficiency from random the noise component. This four component SF model is compared with two other competing SF models in which one of the four components is missing. All the models are estimated using the maximum likelihood method. The models give predicted values of persistent, transient and overall efficiency for each airline and time period. The mean and dispersion of cost efficiency amongst airlines differ by model specifications and according to their geographical area of operations. The performance difference may be a consequence of different market structures and deregulation processes and of specific competitive conditions such as resource availability and strategic alliances with competitors. The results confirm that, in general, none of the airlines is able to achieve full cost efficiency. We find that carriers based in the Asia region are more efficient than those operating in the European and North American regions. The bigger airlines are unable to take full advantage of economies of scale and are not more efficient than their smaller cousins.
This paper examines the efficiency of international airlines for the period 1998-2012 using some competing stochastic frontier (SF) panel data models. It estimates a cost function for multi-output airline services, separating passenger and goods transportation at the national and international levels. Our preferred SF model distinguishes airlines heterogeneity from time-invariant persistent inefficiency, and transient (time-varying) inefficiency from random the noise component. This four component SF model is compared with two other competing SF models in which one of the four components is missing. All the models are estimated using the maximum likelihood method. The models give predicted values of persistent, transient and overall efficiency for each airline and time period. The mean and dispersion of cost efficiency amongst airlines differ by model specifications and according to their geographical area of operations. The performance difference may be a consequence of...
This paper examines the efficiency of international airlines for the period 1998-2012 using some competing stochastic frontier (SF) panel data models. It estimates a cost function for multi-output airline services, separating passenger and goods transportation at the national and international...
Almas Heshmati, Subal C. Kumbhakar, Jungsuk Kim -
In recent years there has been an increase in the interest in contractual flexibility in infrastructure investments, especially in Public-Private Partnership agreements, characterized by the uncertainty derived from the long duration of contracts. This has led to the extension of the theory of real options to the field of infrastructures, as an appropriate methodology for analyzing flexibility in contracts. Within this line of research, this paper focuses on the analysis of the option of early reversion of road concessions, as a right held by the Public Administration and whose value depends on the evolution of a random variable, the volume of traffic. The real option approach is applied to the case study of a road concession in Spain, consequently obtaining significant values for the probability of exercising the option. More generally, this paper contributes to characterizing the early reversion option as a practical tool that can be used by the Administration for the implementation of the infrastructure policy.
In recent years there has been an increase in the interest in contractual flexibility in infrastructure investments, especially in Public-Private Partnership agreements, characterized by the uncertainty derived from the long duration of contracts. This has led to the extension of the theory of real options to the field of infrastructures, as an appropriate methodology for analyzing flexibility in contracts. Within this line of research, this paper focuses on the analysis of the option of early reversion of road concessions, as a right held by the Public Administration and whose value depends on the evolution of a random variable, the volume of traffic. The real option approach is applied to the case study of a road concession in Spain, consequently obtaining significant values for the probability of exercising the option. More generally, this paper contributes to characterizing the early reversion option as a practical tool that can be used by the Administration for the...
In recent years there has been an increase in the interest in contractual flexibility in infrastructure investments, especially in Public-Private Partnership agreements, characterized by the uncertainty derived from the long duration of contracts. This has led to the extension of the theory of...
Antonio Sánchez Soliño, Antonio L. Lara Galera, Fernando Cabero Colín