DocumentCode :
2641474
Title :
Estimating Path Travel-Time Reliability
Author :
Rakha, Hesham ; El-Shawarby, Ihab ; Arafeh, Mazen ; Dion, Francois
Author_Institution :
Dept. of Civil & Environ. Eng., Virginia Tech Transp. Inst., Blacksburg, VA
fYear :
2006
fDate :
17-20 Sept. 2006
Firstpage :
236
Lastpage :
241
Abstract :
The estimation of path or trip travel-time reliability is critical to any advanced traveler information system. The state-of-practice procedures for estimating path travel-time reliability assumes that travel times follow a normal distribution and requires a measure of trip travel-time variance. The study analyzes AVI data from San Antonio and demonstrates through goodness-of-fit tests that the assumption of normality is, from a theoretical standpoint, inconsistent with field travel-time observations and that a lognormal distribution is more representative of roadway travel times. However, visual inspection of the data demonstrates that the normality assumption may be sufficient from a practical standpoint given its computational simplicity. The paper then proposes five methods for the estimation of path travel-time variance from its component segment travel-time variances. The analysis demonstrates that computing the trip travel-time coefficient of variation as the conditional expectation over all realizations of roadway segments provides estimates within 13% of field observations for both uncongested and congested conditions
Keywords :
estimation theory; normal distribution; road traffic; traffic information systems; advanced traveler information system; lognormal distribution; normal distribution; path travel-time reliability; roadway segments; trip travel-time coefficient; trip travel-time variance; visual inspection; Distributed computing; Fluctuations; Fluid flow measurement; Gaussian distribution; Intelligent transportation systems; Stability; Surveillance; Testing; Time measurement; Vehicles;
fLanguage :
English
Publisher :
ieee
Conference_Titel :
Intelligent Transportation Systems Conference, 2006. ITSC '06. IEEE
Conference_Location :
Toronto, Ont.
Print_ISBN :
1-4244-0093-7
Electronic_ISBN :
1-4244-0094-5
Type :
conf
DOI :
10.1109/ITSC.2006.1706748
Filename :
1706748
Link To Document :
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