Implementing the maximum likelihood methodology to measure a driver’s critical gap

Tian, Zong; Vandehey, Mark; Robinson, B. W.; Kittelson, Wayne; Kyte, Michael; Troutbeck, R J; Brilon, Werner; Wu, Ning

doi:10.1016/s0965-8564(98)00044-5

Cited by 66 publications

(61 citation statements)

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“…Based on the outcome of a comprehensive analysis of technical literature (see e.g. [13,19,20,26]), the maximum likelihood method has been suggested and used to estimate the critical headway; see e.g. the best-known manuals for traffic and transportation engineering [18,27].…”

Section: Review Of Related Literature On Roundaboutsmentioning

confidence: 99%

“…However, since variability and heterogeneity characterize drivers' population, the assumptions above introduced can produce erroneous or unreasonably high estimates of roundabout capacity. Tian et al [26] highlighted that the accurate estimation of the critical headway and the follow-up headway can be reached when one considers the specific conditions of the site, as the geometric design of the intersection and the approach grade, the types of vehicle and traffic movements. Respecting this, Kyte et al [29] found that data relating to a specific site usually produce higher forecasts than the forecasts based on general values; thus, a high-level uncertainty may be associated with the gap acceptance parameters and great variability in estimation of site-specific critical headway and follow-up headway can be observed.…”

Section: Review Of Related Literature On Roundaboutsmentioning

confidence: 99%

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Exploring the uncertainty in capacity estimation at roundabouts

Giuffrè

Granà

Tumminello

2017

Eur. Transp. Res. Rev.

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Purpose In gap-acceptance theory the critical and the followup headways have a significant role in determining roundabout entry capacities which in turn depend on circulating flow rates under a specified arrival headway distribution. Calculation considers single mean values of the gap-acceptance parameters, neglecting the inherent variations in these random variables and providing a single value of entry capacity. The purpose of this paper is to derive the entry capacity distribution which accounts for the variations of the contributing (random) variables and suggest how to consider this issue in the operational analysis of the roundabouts. Methods We performed a Monte Carlo simulation to get the distribution of entry capacity and found Crystal Ball software effective for performing the random sampling from the probability density functions of each contributing parameter. A steady-state model of capacity was used for performing many runs; in each run, the values of each contributing parameter were randomly drawn from the corresponding distributions. Results The paper presents the first simulations and the entry capacity distributions at roundabouts, once the probability distributions of the headways were assumed. The results of the analysis were expressed probabilistically, meaning that the probability distributions of capacity rather than the simple point estimates were obtained. Conclusions Comparing the capacity values based on a metaanalytic estimation of critical and follow-up headways and the capacity functions based on the probability distributions of the model parameters, more insights in developing an appropriate approach to capacity estimation at roundabouts can be gained.

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Section: Review Of Related Literature On Roundaboutsmentioning

confidence: 99%

Section: Review Of Related Literature On Roundaboutsmentioning

confidence: 99%

Exploring the uncertainty in capacity estimation at roundabouts

Giuffrè

Granà

Tumminello

2017

Eur. Transp. Res. Rev.

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“…According to Tian et al (1999), the mean critical headway could be calculated and used in various gap acceptance capacity and delay models, since it was an acceptable quantity for representing the average driver behavior.…”

Section: Estimation Of the Critical Headway And The Follow-up Headwaymentioning

confidence: 99%

Methodological Frontier in Operational Analysis for Roundabouts: A Review

Giuffrè

Granà

Tumminello

2016

Front. Built Environ.

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Several studies and researches have shown that modern roundabouts are safe and effective as engineering countermeasures for traffic calming, and they are now widely used worldwide. The increasing use of roundabouts and, more recently, turbo and flower roundabouts, has induced a great variety of experiences in the field of intersection design, traffic safety, and capacity modeling. As for unsignalized intersections, which represent the starting point to extend knowledge about the operational analysis to roundabouts, the general situation in capacity estimation is still characterized by the discussion between gap acceptance models and empirical regression models. However, capacity modeling must contain both the analytical construction and then solution of the model, and the implementation of driver behavior. Thus, issues on a realistic modeling of driver behavior by the parameters that are included into the models are always of interest for practitioners and analysts in transportation and road infrastructure engineering. Based on these considerations, this paper presents a literature review about the key methodological issues in the operational analysis of modern roundabouts. Focus is made on the aspects associated with the gap acceptance behavior, the derivation of the analytical-based models, and the calculation of parameters included into the capacity equations, as well as steady-state and non-steady-state conditions and uncertainty in entry capacity estimation. At last, insights on future developments of the research in this field of investigation will be also outlined.

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“…Ning WU (1999) [3] performed a simplest configuration with one Major stream and one Minor stream and a new universal capacity formula is introduced. Tian et.al (1999) [4] showed that most of the capacity calculation procedures for two-way stop-controlled (TWSC) intersections are based on gap acceptance models. Wan Hashim et.al (2007) [6] showed that Critical Gap Acceptance procedure is still widely used for estimating capacity of unsignalized intersection.…”

Section: Introductionmentioning

confidence: 99%