| 1. |
- Bierlaire, Michel, et al.
(författare)
-
A latent route choice model in Switzerland
- 2006
-
Ingår i: Proceedings of the European Transport Conference.
-
Konferensbidrag (refereegranskat)abstract
- Rature, for example the C-Logit (Cascetta et al., 1996), Path Size Logit (Ben-Akiva and Bierlaire, 1999), Link-Nested Logit (Vovsha and Bekhor, 1998) and subnetwork (Frejinger and Bierlaire, 2006) models. A latent cho- sen route corresponds to an unobserved choice where only an approximate choice description is available. Instead of an exact route description, trav- ellers describe their choice in terms of a sequence of locations and cities that they have traversed, without the need to relate the actual network used by the analyst. We compute the probability of an (aggregate) observation with an un- derlying route choice model using a detailed network description and actual paths. In this context, not only several routes can correspond to the same observation, but the exact origin-destination pair is not necessarily known. We therefore consider several possible origin-destination pairs and their as- sociated set of routes, generated by a choice set generation algorithm. We derive from this list the probability of each observation, in order to perform the maximum likelihood estimation of the route choice model. The methodology is illustrated by estimating Path Size Logit and sub- network models using a dataset collected in Switzerland. This application is one of few based on revealed preferences (RP) data that are presented in the literature. In addition, the network used here (39411 unidirectional links and 14841 nodes) is to our knowledge the largest network used for evaluation of route choice models based on RP data. The estimation results are very sat- isfactory. Indeed, they do not only show that it is possible to estimate route choice models based on aggregate observations, but also that the parameter estimates are stable across different types of models and that the standard errors are small.
|
|
| 2. |
- Bierlaire, Michel, et al.
(författare)
-
An analysis of the implicit choice set generation using the constrained multinomial logit model
- 2010
-
Ingår i: Transportation Research Record. - : SAGE Publications. - 0361-1981 .- 2169-4052. ; 2175, s. 92-97
-
Tidskriftsartikel (refereegranskat)abstract
- Discrete choice models are defined conditional to the analyst's knowledge of the actual choice set. The common practice for many years has been to assume that individual-based choice sets can be deterministically generated on the basis of the choice context and characteristics of the decision maker. This assumption is not valid or not applicable in many situations, and probabilistic choice set formation procedures must be considered. The constrained multinomial logit model (CMNL) has recently been proposed as a convenient way to deal with this issue, as it is also appropriate for models with a large choice set. In this paper, how well the implicit choice set generation of the CMNL approximates the explicit choice set generation is analyzed as described in earlier research. The results based on synthetic data show that the implicit choice set generation model may be a poor approximation of the explicit model
|
|
| 3. |
|
|
| 4. |
|
|
| 5. |
|
|
| 6. |
- Börjesson, Maria, 1974-, et al.
(författare)
-
Within-Individual Variation in Preferences Equity Effects of Congestion Charges
- 2013
-
Ingår i: Transportation Research Record. - : SAGE Publications. - 0361-1981 .- 2169-4052. ; :2382, s. 92-101
-
Tidskriftsartikel (refereegranskat)abstract
- The purpose of this research was to explore how the values of travel time (VTT) and preferences for different modes vary within individuals compared with the variation between observed trips. With 6-week revealed preference panel data and stated preference data from a mode choice context, both collected in Switzerland, a revealed stated preference logit mode choice model was estimated. The model was applied to simulate how VTT and change in consumer surplus vary across trips within and between individuals over the 6 weeks in response to a hypothetical congestion-charging scheme. The variation in VTT arising from income differences was found to be substantially smaller than the variation in VTT between trips. Moreover, the variability in VTT averaged over all trips within each individual was considerably smaller than the variability in VTT for all observed trips. Therefore, the assumption that variation in VTT between observed trips reflects the variation in the average VTT between individuals, which is usually made in equity analyses, will over-state the between-individual variation. The results suggest that if intraindividual variation in preferences is not taken into account, the negative equity effects of congestion charges are likely to be overestimated.
|
|
| 7. |
|
|
| 8. |
- Farooq, Bilal, et al.
(författare)
-
Simulation based population synthesis
- 2013
-
Ingår i: Transportation Research Part B. - : Elsevier BV. - 0191-2615 .- 1879-2367. ; 58:SI, s. 243-263
-
Tidskriftsartikel (refereegranskat)abstract
- Microsimulation of urban systems evolution requires synthetic population as a key input. Currently, the focus is on treating synthesis as a fitting problem and thus various techniques have been developed, including Iterative Proportional Fitting (IPF) and Combinatorial Optimization based techniques. The key shortcomings of these procedures include: (a) fitting of one contingency table, while there may be other solutions matching the available data (b) due to cloning rather than true synthesis of the population, losing the heterogeneity that may not have been captured in the microdata (c) over reliance on the accuracy of the data to determine the cloning weights (d) poor scalability with respect to the increase in number of attributes of the synthesized agents. In order to overcome these shortcomings, we propose a Markov Chain Monte Carlo (MCMC) simulation based approach. Partial views of the joint distribution of agent's attributes that are available from various data sources can be used to simulate draws from the original distribution. The real population from Swiss census is used to compare the performance of simulation based synthesis with the standard IPF. The standard root mean square error statistics indicated that even the worst case simulation based synthesis (SRMSE = 0.35) outperformed the best case IPF synthesis (SRMSE = 0.64). We also used this methodology to generate the synthetic population for Brussels, Belgium where the data availability was highly limited.
|
|
| 9. |
- Fetiarison, Mamy, et al.
(författare)
-
Evaluation of pedestrian data collection methods within a simulation framework
- 2010
-
Ingår i: Proceedings of the European Transport Conference.
-
Konferensbidrag (refereegranskat)abstract
- The estimation and validation of pedestrian behavioral models requires large amounts of detailedand appropriate data, the collection of which is a costly and time-consuming undertaking.The identification and design of an appropriate data collection method therefore is of great importance,which, however, is an arduous and itself time-consuming task. This article describesa software laboratory that facilitates the design of pedestrian data collection campaigns.
|
|
| 10. |
- Flötteröd, Gunnar, et al.
(författare)
-
Bayesian demand calibration for dynamic traffic simulations
- 2011
-
Ingår i: Transportation Science. - : Institute for Operations Research and the Management Sciences (INFORMS). - 0041-1655 .- 1526-5447. ; 45:4, s. 541-561
-
Tidskriftsartikel (refereegranskat)abstract
- We present an operational framework for the calibration of demand models for dynamic traffic simulations, where calibration refers to the estimation of a structurally predefined model's parameters from real data. Our focus is on disaggregate simulators that represent every traveler individually. We calibrate, also at an individual level, arbitrary choice dimensions within a Bayesian framework, where the analyst's prior knowledge is represented by the dynamic traffic simulator itself and the measurements are comprised of time-dependent traffic counts. The approach is equally applicable to an equilibrium-based planning model and to a telematics model of spontaneous and imperfectly informed drivers. It is based on consistent mathematical arguments, yet it is applicable in a purely simulation-based environment and, as our experimental results show, is capable of handling large scenarios.
|
|
| 11. |
|
|
| 12. |
|
|
| 13. |
|
|
| 14. |
|
|
| 15. |
- Flötteröd, Gunnar, et al.
(författare)
-
Metropolis-Hastings sampling of paths
- 2011
-
Rapport (övrigt vetenskapligt/konstnärligt)abstract
- We consider the previously unsolved problem of sampling cycle-free pathsaccording to a given distribution from a general network. The problem isdifficult because of the combinatorial number of alternatives, which prohibitsa complete enumeration of all paths and hence also forbids to computethe normalizing constant of the sampling distribution. The problemis important because the ability to sample from a known distribution introducesmathematical rigor into many applications that range from routeguidance to the estimation of choice models with sampling of alternatives.
|
|
| 16. |
|
|
| 17. |
- Fosgerau, Mogens, et al.
(författare)
-
Choice probability generating functions
- 2013
-
Ingår i: Journal of Choice Modelling. - : ELSEVIER SCI LTD. - 1755-5345. ; 8, s. 1-18
-
Tidskriftsartikel (refereegranskat)abstract
- This paper considers discrete choice, with choice probabilities coming from maximization of preferences from a random utility field perturbed by additive location shifters (ARUM). Any ARUM can be characterized by a choice-probability generating function (CPGF) whose gradient gives the choice probabilities, and every CPGF is consistent with an ARUM. We relate CPGF to multivariate extreme value distributions, and review and extend methods for constructing CPGF for applications. The choice probabilities of any ARUM may be approximated by a cross-nested logit model. The results for ARUM are extended to competing risk survival models.
|
|
| 18. |
- Frejinger, Emma, 1979-, et al.
(författare)
-
Capturing correlation in route choice models using subnetworks
- 2006
-
Ingår i: Proceedings of the Swiss Transportation Research Conference.
-
Konferensbidrag (refereegranskat)abstract
- When using random utility models for a route choice problem, choice set generation and correlation among alternatives are two issues that make the modelling complex. In this paper we propose a modelling approach where the path overlap is captured with a subnetwork. A subnetwork is a simplification of the road network only containing easy identifiable and behaviourally relevant roads. In practise, the subnetwork can easily be defined based on the route network hierarchy. We propose a model where the subnetwork is used for defining the correlation structure of the choice model. The motivation is to explicitly capture the most important correlation without considerably increasing the model complexity. We present estimation results of a factor analytic specification of a mixture of Multinomial Logit model, where the correlation among paths is captured both by a Path Size attribute and error components. The estimation is based on a GPS dataset collected in the Swedish city of Borlänge. The results show a significant increase in model fit for the Error Component model compared to a Path Size Logit and Multinomial Logit models. Moreover, the correlation parameters are significant. We also analyse the performance of the different models regarding prediction of choice probabilities. The results show a better performance of the Error Component model compared to the Path Size Logit and Multinomial Logit models.
|
|
| 19. |
|
|
| 20. |
- Frejinger, Emma, 1979-, et al.
(författare)
-
Capturing correlation with subnetworks in route choice models
- 2007
-
Ingår i: Transportation Research Part B. - : Elsevier BV. - 0191-2615 .- 1879-2367. ; 41:3, s. 363-378
-
Tidskriftsartikel (refereegranskat)abstract
- When using random utility models for a route choice problem, a critical issue is the significant correlation among alternatives. There are basically two types of models proposed in the literature to address it: (i) a deterministic correction of the path utilities in a Multinomial Logit model (Such as the Path Size Logit or the C-Logit models) and (ii) an explicit modeling of the correlation through assumptions about the error terms, and the use of advanced discrete choice models such as the Cross-Nested Logit or the Error Component models. The first is simple, easy to handle and often used in practice. Unfortunately, it does not correctly capture the correlation structure, as we discuss in details in the paper. The second is more consistent with the modeling objectives, but very complicated to specify and estimate. The modeling framework proposed in this paper allows the analyst to control the trade-off between the simplicity of the model and the level of realism. Within this framework, the key concept capturing the correlation structure is called subnetwork. A subnetwork is a simplification of the road network only containing easy identifiable and behaviorally relevant roads. In practice, the subnetwork can easily be defined based oil the route network hierarchy. The importance and the originality of our approach lie in the possibility to capture the most important correlation without considerably increasing the model complexity. This makes it suitable for a wide spectrum of application,.;, namely involving realistic large-scale networks. As an illustration, we present estimation results of a factor analytic specification of a mixture of Multinomial Logit model, where the correlation among paths is captured by error components. The estimation is based on a GPS dataset collected in the Swedish city of Borlange. The results show a significant increase in model fit and forecasting performance for the Error Component model compared to a Path Size Logit model. Moreover, the correlation parameters are significant.
|
|
| 21. |
|
|
| 22. |
|
|
| 23. |
- Frejinger, Emma, 1979-, et al.
(författare)
-
Random Sampling of Alternatives for Route Choice Modeling
- 2007
-
Ingår i: Swiss Transport Research Conference.
-
Konferensbidrag (refereegranskat)abstract
- In this paper we present a new point of view on choice set generation for route choice models. When modeling route choice behavior using random utility models choice sets of paths need to be defined. Existing approaches generate paths and assume that actual choice sets are found. On the contrary, we assume that actual choice sets are the sets of all paths connecting each origindestination pair. These sets are however unknown and we propose a stochastic path generation algorithm that corresponds to an importance sampling approach. The path utilities should then be corrected according to the used sampling protocol in order to obtain unbiased parameter estimates. We derive such a sampling correction for the proposed algorithm. We present numerical results based on synthetic data. The results show that the model including sampling correction yields unbiased coefficient estimates but we also make important observations concerning the Path Size attribute. Namely, it biases the estimation results if it is not computed based on the true correlation structure. These results suggest that the Path Size attribute should be computed based on as many alternatives as possible, more than in the generated choice sets.
|
|
| 24. |
- Frejinger, Emma, 1979-, et al.
(författare)
-
Route choice modeling with network-free data
- 2008
-
Ingår i: Transportation Research Part C. - : Elsevier BV. - 0968-090X .- 1879-2359. ; 16:2, s. 187-198
-
Tidskriftsartikel (refereegranskat)abstract
- Route Choice models arc difficult to design and to estimate for various reasons. In this paper we focus on issues related to data. Indeed, real data in its original format are not related to the network used by the modeler and do therefore not correspond to path definitions. Typical examples arc data collected with the Global Positioning System (GPS) or respondents describing chosen itineraries to interviewers. Data manipulation is then necessary in order to obtain network compliant paths. We argue that such manipulations introduce bias and errors and should be avoided. We propose a general modeling framework that reconcile network-free data with a network based model without data manipulations. The concept that bridges the gap between the data and the model is called Domain of Data Relevance and corresponds to a physical area in the network where a given piece of data is relevant. We illustrate the framework on simple examples for two different types of data (GPS data and reported trips). Moreover, we present estimation results of Path Size Logit and Subnetwork models based on a dataset of reported trips collected in Switzerland. The network is to our knowledge the largest one used in the literature for route choice analysis based on revealed preferences data.
|
|
| 25. |
|
|
| 26. |
|
|
| 27. |
- Glerum, Aurélie, et al.
(författare)
-
A dynamic discrete-continuous choice model of car ownership and usage
- 2013
-
Ingår i: Proceedings of the 13th Swiss Transport Research Conference. ; , s. 1-13
-
Konferensbidrag (refereegranskat)abstract
- In this paper we present the methodologicalframework of adynamic discrete-continuouschoicemodel (DDCCM)of car ownership, usage and fuel type. The approach consistsof embeddinga discrete-continuous choice model into adynamic programming (DP)framework. This workproposes the following novel features. First, decisions are modeled at a household level. Sec-ond, we consider an extensive choice variable which involves the car replacement decision,the annual driving distance, the fuel type, the decision to take a company car, or a new versussecond-hand car.
|
|
| 28. |
- Glerum, Aurélie, et al.
(författare)
-
A dynamic discrete-continuous choice model of car ownership, usage and fuel type
-
Annan publikation (övrigt vetenskapligt/konstnärligt)abstract
- This paper presents a dynamic discrete-continuous choice model of car ownership, usage, and fuel type that embeds a discrete-continuous choice model into a dynamic programming framework to account for the forward-looking behavior of households in the context of car acquisition. More specifically, we model the transaction type, the choice of fuel type, and the annual driving distance for up to two cars in the household. We present estimation and cross-validation results based on a subsample of the Swedish population that is obtained from combining the population and car registers. Finally we apply the model to analyze a hypothetical policy that consists of a subsidy that reduces the annual cost of diesel cars.
|
|
| 29. |
|
|
| 30. |
|
|
| 31. |
- Huibregtse, Olga, et al.
(författare)
-
Optimization of evacuation instructions as a fixed-point problem.
- 2011
-
Ingår i: Proceedings of the Swiss Transport Research Conference (STRC). - Monte Verita/Ascona, Switzerland.
-
Konferensbidrag (refereegranskat)abstract
- In this paper, a new framework is presented to optimize evacuation instructions. By giving optimized instructions to the evacuees (for example about which route to take), traffic conditions and, therefore, the evacuation efficiency are optimized. To solve the problem in an efficient way, the problem is decomposed into three simpler problems, namely the optimization of turning fractions, the optimization of instructions given the turning fractions, and the approximation of compliance behavior. Mutual consistency of these sub-problems is enforced through a fixed-point formulation.
|
|
| 32. |
- Hurtubia, Ricardo, et al.
(författare)
-
Comparative analysis of hedonic rents and maximum bids in a land-use simulation context
- 2010
-
Ingår i: Proceedings of the Swiss Transport Research Conference (STRC). - Monte Verita/Ascona, Switzerland.
-
Konferensbidrag (refereegranskat)abstract
- The choice and bid-auction approaches for location choice modeling are analyzed and compared, with a focus in their rent estimation models: hedonic prices and expected maximum bids, respectively. A simulation experiment is performed over synthetic data, comparing several specifications for hedonic rent models with the expected maximum bid. Results show that the hedonic approach generates rents that diverge from the maximum bids. This results indicate that hedonic rent models can be improved by accounting for elements like household’s heterogeneity in preferences and market conditions or constraints.
|
|
| 33. |
- Hurtubia, Ricardo, et al.
(författare)
-
Estimation techniques for MEV models with sampling of alternatives
- 2010
-
Ingår i: Proceedings of the European Transport Conference. - Glasgow, Scotland.
-
Konferensbidrag (refereegranskat)abstract
- Estimation of MEV models with large choice sets requires sampling of alternatives, which might be a difficult task due to the correlated-structure of the error terms. Standard sampling techniques like the ones traditionally used for Multinomial Logit models cannot be directly applied in the estimation of more complex MEV models. State of the art estimators for MEV models with sampling of alternatives either require knowledge of the full choice set or produce biased estimates for small sample sizes.This paper proposes two estimation techniques for MEV models with sampling of alternatives. The first technique is based on bootstrapping and allows to reduce the bias for existing estimators. A Monte Carlo simulation experiment is performed to show how this technique reduce the bias of a state-of the-art estimator for a Nested Logit model considering sampling of alternatives. The second technique introduces a new estimator, based on importance sampling of alternatives . A second Monte Carlo experiment is performed to compare this estimator with the current state of the art. The proposed estimator generates unbiased parameter estimates for a Nested Logit model considering small sample sizes. The techniques can be easily applied to other members of the MEV family of models, like the Cross-Nested Logit.
|
|
| 34. |
|
|
| 35. |
- Kazagli, Evanthia, et al.
(författare)
-
Revisiting the route choice problem : A modeling framework based on mental representations
- 2016
-
Ingår i: Journal of Choice Modelling. - : Elsevier. - 1755-5345. ; 19, s. 1-23
-
Tidskriftsartikel (refereegranskat)abstract
- We present a new approach for modeling and analyzing route choice behavior. It is motivated by the need to reduce the complexity of the state-of-the-art choice models. It is inspired by the simplifications done by the travelers, using representations of their surrounding space. The proposed framework is based on elements designed to mimic the mental representations used by travelers, denoted as Mental Representation Items (MRIs). It allows the modeler to adjust the level of complexity according to the needs of the specific application. This paper describes how operational models based on MRIs can be derived and discusses the applications of these models to traffic assignment and route guidance systems. We report estimation results using revealed preference data to demonstrate the applicability and validity of the approach.
|
|
| 36. |
|
|
| 37. |
|
|
| 38. |
- Osorio, Carolina, et al.
(författare)
-
Computing full link state distributions in the dynamic network loading problem
- 2010
-
Ingår i: 2010 Proceedings European Transport Conference.
-
Konferensbidrag (övrigt vetenskapligt/konstnärligt)abstract
- This paper derives a new dynamic network loading model that yields full link queue length distributions, properly accounts for spillback, and maintains a differentiable mapping from the dynamic demand on the dynamic link states. The approach builds upon an existing stationary queuing network model that is based on finite capacity queuing theory. The original model is specified in terms of a set of differential equations, which in the new model are carried over to a set of equally smooth difference equations. The representation of full dynamic link state distributions has so far been reserved to microsimulations. The approach used in this paper differs from previous work in that it (i) exploits closed-form results from queuing theory, (ii) provides the additional benefit of a closed-form expression of the system's stationary state, and (iii) consists of one integrated set of smooth equations whereas previous research deployed a switching logic between multiple linear models. Essentially, the original stationary model the authors use starts from the link state distributions from the standard queuing theory global balance equations. Coupling equations are used to capture the network-wide interactions between these single-link models. The new dynamic version of this model consists of a dynamic link model and a static node model. The global balance equations are replaced by a discrete-time closed-form expression for the transient link state distributions. This expression guides the link model's transition from the full queue distribution of one time step to the next. It is available in closed form under the reasonable assumption of constant link boundary conditions during a simulation step. No dynamics are introduced into the node model, which maintains the structure of the original stationary model. Disposing of both the dynamic model and the according stationary model is useful because it allows for the evaluation of the stationary limit of the dynamic model at a low computational cost. In the analysis of the new model, this consistency is checked by running the dynamic model until it is stationary and comparing the resulting link state distributions with those of the original model. The realism of the new model's dynamics is investigated by comparison with empirical distributions obtained from a calibrated microscopic simulation model of the city of Lausanne during the evening peak hour. There are various applications of the new model. Full dynamic link state distributions can be used as inputs for route or departure time choice models that capture risk-averse behavior. The analytically tractable form of the stationary model has enabled engineers in the past to use it to solve traffic control problems using gradient-based optimization algorithms. Since the dynamic formulation preserves the smoothness of the original model, the authors expect it to be of equal interest for problems that involve derivative-based algorithms, including solution procedures for the dynamic traffic assignment problem.
|
|
| 39. |
- Osorio, Carolina, et al.
(författare)
-
Dynamic network loading : a differentiable model that derives link state distributions
- 2011
-
Ingår i: Papers selected for the 19th International Symposium on Transportation and Traffic Theory. - : Elsevier. ; , s. 364-381
-
Konferensbidrag (övrigt vetenskapligt/konstnärligt)abstract
- We present a dynamic network loading model that yields queue length distributions, accounts for spillbacks, and maintains a differentiable mapping from the dynamic demand on the dynamic queue lengths. The model also captures the spatial correlation of all queues adjacent to a node, and derives their joint distribution. The approach builds upon an existing stationary queueing network model that is based on finite capacity queueing theory. The original model is specified in terms of a set of differentiable equations, which in the new model are carried over to a set of equally smooth difference equations. The physical correctness of the new model is experimentally confirmed in several congestion regimes. A comparison with results predicted by the kinematic wave model (KWM) shows that the new model correctly represents the dynamic build-up, spillback, and dissipation of queues. It goes beyond the KWM in that it captures queue lengths and spillbacks probabilistically, which allows for a richer analysis than the deterministic predictions of the KWM. The new model also generates a plausible fundamental diagram, which demonstrates that it captures well the stationary flow/density relationships in both congested and uncongested conditions.
|
|
| 40. |
- Osorio, Carolina, et al.
(författare)
-
Dynamic network loading: A stochastic differentiable model that derives link state distributions
- 2011
-
Ingår i: Transportation Research Part B. - : Elsevier BV. - 0191-2615 .- 1879-2367. ; 45:9, s. 1410-1423
-
Tidskriftsartikel (refereegranskat)abstract
- We present a dynamic network loading model that yields queue length distributions, accounts for spillbacks, and maintains a differentiable mapping from the dynamic demand on the dynamic queue lengths. The model also captures the spatial correlation of all queues adjacent to a node, and derives their joint distribution. The approach builds upon an existing stationary queueing network model that is based on finite capacity queueing theory. The original model is specified in terms of a set of differentiable equations, which in the new model are carried over to a set of equally smooth difference equations. The physical correctness of the new model is experimentally confirmed in several congestion regimes. A comparison with results predicted by the kinematic wave model (KWM) shows that the new model correctly represents the dynamic build-up, spillback and dissipation of queues. It goes beyond the KWM in that it captures queue lengths and spillbacks probabilistically, which allows for a richer analysis than the deterministic predictions of the KWM. The new model also generates a plausible fundamental diagram, which demonstrates that it captures well the stationary flow/density relationships in both congested and uncongested conditions.
|
|
