Calibration of Platoon Dispersion Parameters on the Basis of Link Travel Time Statistics

2000 ◽  
Vol 1727 (1) ◽  
pp. 89-94 ◽  
Author(s):  
Lei Yu
Keyword(s):  
Travel Time ◽  
Traffic Management ◽  
Dispersion Model ◽  
Time Data ◽  
Dispersion Parameters ◽  
Smoothing Factor ◽  
Travel Time Data ◽  
Platoon Dispersion ◽  
Advanced Traffic Management System ◽  
Link Travel Time

A calibration technique for platoon dispersion parameters for the widely used TRANSYT platoon dispersion model is presented. This technique calibrates platoon dispersion factor, travel time factor, and smoothing factor directly from the average link travel time and its standard deviation and can capture practically all of the roadway and traffic conditions in the field such as road grades, curvature, parking, opposing flow interference, traffic volume, and other sources of impedance. The technique is especially suited for applications in advanced traffic management system networks in which the required link travel time data could be obtained on a real-time basis. TRANSYT’s implementation of two scenarios is examined. The first scenario inputs the calibrated platoon dispersion parameter, with the result being that the smoothing factor used by TRANSYT is different from the calibrated parameter. The second scenario inputs a revised platoon dispersion factor, which is designed to make the smoothing factor used by TRANSYT identical to the calibrated parameter. This examination induces a recommendation that the TRANSYT input card or its internal calculation procedure for platoon dispersion be revised so that the average link travel time in the geometric distributed platoon dispersion model is consistent with those from the same model. The calibration of platoon dispersion parameters with field-collected link travel time data shows that platoon dispersion parameters are different for different standard deviations of link travel times even on the same street, and, therefore, the platoon dispersion parameters must be calibrated on a site-specific basis.

Research on Link Travel Time Reliability Model Based on Massive Expressway Toll Data

2014 ◽  
Vol 505-506 ◽  
pp. 719-726 ◽  
Author(s):  
Tao Wen ◽  
Chang Cheng Li ◽  
Chun Jiang Che ◽  
Lian De Zhong ◽  
Xin Xin
Keyword(s):  
Normal Distribution ◽  
Travel Time ◽  
Estimation Method ◽  
Model Parameters ◽  
Reliability Model ◽  
Travel Time Reliability ◽  
Time Data ◽  
Moment Estimation ◽  
Travel Time Data ◽  
Link Travel Time

Massive expressway toll data contained lots of valuable information. However, the skills of mining and analyzing toll data were limited currently. This study explored the modeling method of road network travel time reliability based on massive toll data. Firstly, this study obtained travel time data sample of each link at different months, and analyzed travel time statistical properties preliminarily. Secondly, this study used normal distribution, gamma distribution and Weibull distribution to fit travel time data sample, and different statistical indicators were involved to measure the fitting effect. Fitting results showed that normal distribution for link travel time was more rational and acceptable than the others. Thus, this study established link travel time reliability model, and proposed moment estimation method of calibrating the model parameters. In practical application, the reliability model can be used to judge traffic operating posture for expressway management department, and also can be used to forecast travel time information, to provide valuable reference on decision-making for drivers travel plan or route choice.

Dynamic platoon dispersion model based on real-time link travel time

2019 ◽  
Vol 13 (11) ◽  
pp. 1694-1700 ◽  
Author(s):  
Zhihong Yao ◽  
Taorang Xu ◽  
Yang Cheng ◽  
Lingqiao Qin ◽  
Yangsheng Jiang ◽  
...  
Keyword(s):  
Travel Time ◽  
Real Time ◽  
Dispersion Model ◽  
Model Based ◽  
Platoon Dispersion ◽  
Link Travel Time

Depth solution from borehole and travel time data using three-variable hypersurface splines

2001 ◽  
Vol 46 (3) ◽  
pp. 201-211 ◽  
Author(s):  
P.F. Xu ◽  
Z.W. Yu ◽  
H.Q. Tan ◽  
J.X. Ji
Keyword(s):  
Travel Time ◽  
Time Data ◽  
Travel Time Data

Crustal structure in the Transvaal*

1956 ◽  
Vol 46 (4) ◽  
pp. 293-316
Author(s):  
P. G. Gane ◽  
A. R. Atkins ◽  
J. P. F. Sellschop ◽  
P. Seligman
Keyword(s):  
Travel Time ◽  
Crustal Structure ◽  
Time Data ◽  
Lower Velocity ◽  
Travel Time Data ◽  
The Mean

abstract Travel-time data are given at 25 km. intervals between 50 and 500 km. for traverses west, south, east, and north of Johannesburg. These derive from numerous seismograms of Witwatersrand earth tremors taken by means of a triggering technique. The only phases considered to be consistent are those mentioned below, and few signs of a change of velocity with depth were discovered. There were no great differences in the results for the various directions, and the mean results were: P 1 = + 0.24 + Δ / 6.18 sec . S 1 = + 0.37 + Δ / 3.66 sec . P n = + 7.61 + Δ / 8.27 sec . S n = + 11.4 + Δ / 4.73 sec . which give crustal depths of 35.1 and 33.3 km. from P and S data respectively. These depths include about 1.3 km. of superficial material of lower velocity.

Study of teleseismic P I — travel-time data

1970 ◽  
Vol 4 (1) ◽  
pp. 1-23 ◽  
Author(s):  
Jack F. Evernden ◽  
Don M. Clark
Keyword(s):  
Travel Time ◽  
Time Data ◽  
Travel Time Data

Seismic wave travel times from nuclear explosions

1958 ◽  
Vol 48 (4) ◽  
pp. 377-398
Author(s):  
Dean S. Carder ◽  
Leslie F. Bailey
Keyword(s):  
Travel Time ◽  
Travel Times ◽  
Strong Variation ◽  
Time Data ◽  
Owens Valley ◽  
Central California ◽  
Nuclear Explosions ◽  
Travel Time Data ◽  
The Pacific ◽  
Wave Travel

Abstract A large number of seismograph records from nuclear explosions in the Nevada and Pacific Island proving grounds have been collected and analyzed. The Nevada explosions were well recorded to distances of 6°.5 (450 mi.) and weakly recorded as far as 17°.5, and under favorable circumstances as far as 34°. The Pacific explosions had world-wide recording except that regional data were necessarily meager. The Nevada data confirm that the crustal thickness in the area is about 35 km., with associations of 6.1 km/sec. speeds in the crust and 8.0 to 8.2 km/sec. speeds beneath it. They indicate that there is no uniform layering in the crust, and that if higher-speed media do exist, they are not consistent; also, that the crust between the proving grounds and central California shows a thickening probably as high as 70 or 75 km., and that this thickened portion may extend beneath the Owens Valley. The data also point to a discontinuity at postulated depths of 160 to 185 km. Pacific travel times out to 14° are from 4 to 8 sec. earlier than similar continental data partly because of a thinner crust, 17 km. or less, under the atolls and partly because speeds in the top of the mantle are more nearly 8.15 km/sec. than 8.0 km/sec. More distant points, at 17°.5 and 18°.5, indicate slower travel times—about 8.1 km/sec. A fairly sharp discontinuity at 19° in the travel-time data is indicated. Travel times from Pacific sources to North America follow closely Jeffreys-Bullen 1948 and Gutenberg 1953 travel-time curves for surface foci except they are about 2 sec. earlier on the continent, and Arctic and Pacific basin data are about 2 sec. still earlier. The core reflection PcP shows a strong variation in amplitude with slight changes in distance at two points where sufficient data were available.

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