Estimating Route Choice Models from Stochastically Generated Choice Sets on Large-Scale Networks Correcting for Unequal Sampling Probability:Correcting for Unequal Sampling Probability

Route choice is one of the most complex decision-making contexts to represent mathematically, and the most frequently used approach to model route choice consists of generating alternative routes and modeling the preferences of utility-maximizing travelers. The main drawback of this approach is the dependency of the parameter estimates from the choice set generation technique. Bias introduced in model estimation has been corrected only for the random walk algorithm, which has problematic applicability to large-scale networks. This study proposes a correction term for the sampling probability of routes extracted with stochastic route generation. The term is easily applicable to large-scale networks and various environments, given its dependence only on a random number generator and the Dijkstra shortest path algorithm. The implementation for revealed preferences data, which consist of actual route choices collected in Cagliari, Italy, shows the feasibility of generating routes stochastically in a high-resolution network and calculating the correction factor. The model estimation with and without correction illustrates how the correction not only improves the goodness of fit but also turns illogical signs for parameter estimates to logical signs

User perspectives in public transport timetable optimisation

The present paper deals with timetable optimisation from the perspective of minimising the waiting time experienced by passengers when transferring either to or from a bus. Due to its inherent complexity, this bi-level minimisation problem is extremely difficult to solve mathematically, since timetable optimisation is a non-linear non-convex mixed integer problem, with passenger flows defined by the route choice model, whereas the route choice model is a non-linear non-continuous mapping of the timetable. Therefore, a heuristic solution approach is developed in this paper, based on the idea of varying and optimising the offset of the bus lines. Varying the offset for a bus line impacts the waiting time passengers experience at any transfer stop on the bus line.In the bi-level timetable optimisation problem, the lower level is a transit assignment calculation yielding passengers' route choice. This is used as weight when minimising waiting time by applying a Tabu Search algorithm to adapt the offset values for bus lines. The updated timetable then serves as input in the following transit assignment calculation. The process continues until convergence.The heuristic solution approach was applied on the large-scale public transport network in Denmark. The timetable optimisation approach yielded a yearly reduction in weighted waiting time equivalent to approximately 45 million Danish kroner (9 million USD)

"Them or Us": Perceptions, cognitions, emotions, and overt behavior associated with cyclists and motorists sharing the road

In emerging cycling regions, cyclists and motorists are forced to share the road due to cycling infrastructure scarcity. This study investigates the chain of external and internal stimuli, inferred cognition, emotion and overt behavior associated with the road sharing experience. The research methodology consists of a thematic-analysis of a heterogeneous sample of 1,844 talk-backs that were posted in response to news items related to cyclist-motorist traffic crashes in Israel. The results show: (i) cycling infrastructure scarcity and perceptions regarding the natural and legal rights of cyclists to use the road act as primary triggers for the emotional stress associated with road sharing; (ii) motorists and cyclists perceive the road sharing experience as life-threatening situation that induces extreme anxiety, anger and fear; (iii) the overt coping strategies of drivers are confrontive, problem-solving and seeking social-support, while the overt coping strategies of cyclists are escape-avoidance, confrontive and problem-solving

Road signage comprehension and overload: The role of driving style and need for closure

This study looks at the provision of information via traffic signs and its relation with driving styles, need for closure and socio-economic characteristics of road users. A web-based questionnaire allowed collecting information about traffic signs and road surface markings in 12 traffic locations that were presented in two variations: (i) in the first 6 cases, a first configuration contained information that led to ambiguity about the manoeuvres that were legal and a second configuration added traffic signs to eliminate the ambiguity; (ii) in the second 6 cases, a first configuration presented the road environment without signs and a second configuration added traffic signs to verify information redundancy. Respondents indicated for each location which manoeuvres they deemed legal and how many conflicts they estimated without traffic signs, and safety perception and comfort level improved with the traffic signs. Moreover, respondents reported their socio-economic characteristics and filled two questionnaires about need for closure and driving styles. Completed questionnaires from 753 participants from Hungary with expertise in transport and traffic were analysed via statistical and factor analysis, and results reveal that: (i) road users are heterogeneous in their perception and processing of information, as the number of manoeuvres correctly identified as legal relates to their socio-economic characteristics; (ii) the perception of improvements after the provision of information relates also to the road uses' socio-economic characteristics and their driving style and need for closure; (iii) different amounts of information are sufficient for different road users not to feel uncertain regarding manoeuvres being legal at a certain traffic location

Hvem er det, der gentagne gange kører spirituskørsel, og hvor udbredt er recidivisme i Danmark?

Spirituskørsel er stadig et af de største problemer for trafiksikkerheden. 15 % af alle personskadeuheld i Danmark er spiritusuheld, og 25 % af alle trafikdræbte dør i en spiritusulykke. Personer, der gentagne gange kører spirituskørsel, kaldes recidivister. Formålet med denne undersøgelse var at afdække, hvor udbredt fænomenet er i Danmark, om recidivister adskiller sig fra andre trafikanter mht. sociodemografiske faktorer, og om recidivister har øget risiko for at blive involveret i et færdselsuheld. Undersøgelsen er baseret på data fra Danmarks Statistik for perioden 2008-2012 og omfatter alle personer i alderen 18 år eller ældre, i alt 4.260.306 personer. Ved hjælp af chi-square tests og t-tests blev ligheder og forskelle mht. demografiske faktorer analyseret. Logistisk regression blev benyttet til at se, om demografiske faktorer kunne forudsige, hvilke personer der med størst sandsynlighed ville blive recidivister indenfor en femårsperiode. Undersøgelsen viste, at 17 % af dem, der fik en dom for spirituskørsel i 2008, fik mindst én dom til indenfor fem år. Af disse fik 12 % deres anden dom for spirituskørsel inden for samme år. Med hensyn til uheldsrisiko havde recidivister en højere forekomst af uheld med høje promiller. Samlet tyder undersøgelsen på, at recidivisme i højere grad forekommer blandt mænd og blandt personer, der befinder sig i en mindre gunstig socioøkonomisk livssituation, hvor de bor alene, har lav indkomst, ringe uddannelse og øget involvering i lovovertrædelser. Undersøgelsen tyder endvidere på, at omstændighederne omkring spirituskørsel er forskellige for mænd og kvinder, men giver ingen indsigt i, om det at blive taget for spirituskørsel bidrager til at igangsætte en marginaliseringsproces, eller om spirituskørslen sker som led i en eksisterende marginaliseret samfundsmæssig position

Timetable-based simulation method for choice set generation in large-scale public transport networks

The composition and size of the choice sets are a key for the correct estimation of and prediction by route choice models. While existing literature has posed a great deal of attention towards the generation of path choice sets for private transport problems, the same does not apply to public transport problems. This study proposes a timetable-based simulation method for generating path choice sets in a multimodal public transport network. Moreover, this study illustrates the feasibility of its implementation by applying the method to reproduce 5131 real-life trips in the Greater Copenhagen Area and to assess the choice set quality in a complex multimodal transport network. Results illustrate the applicability of the algorithm and the relevance of the utility specification chosen for the reproduction of real-life path choices. Moreover, results show that the level of stochasticity used in choice set generation should be high in order to provide stable parameter estimates when the choice sets are used for estimation regardless of the initial parameters for choice set generation. Last, results illustrate that adding heterogeneity across travellers should be required because coverage increases significantly, a relevant result considering that models are becoming more disaggregate in nature in real-life applications