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Freeway travel speed calculation model based on ETC transaction data.

Weng J, Yuan R, Wang R, Wang C - Comput Intell Neurosci (2014)

Bottom Line: The reduction coefficient α and reliable weight θ for sample vehicle speed were introduced in the model.The experiments results demonstrated that the average relative error was about 6.5% which means that the freeway travel speed could be estimated by the proposed model accurately.The proposed model is helpful to promote the level of the freeway operation monitoring and the freeway management, as well as to provide useful information for the freeway travelers.

View Article: PubMed Central - PubMed

Affiliation: Beijing Key Laboratory of Traffic Engineering, Beijing University of Technology, Beijing 100124, China.

ABSTRACT
Real-time traffic flow operation condition of freeway gradually becomes the critical information for the freeway users and managers. In fact, electronic toll collection (ETC) transaction data effectively records operational information of vehicles on freeway, which provides a new method to estimate the travel speed of freeway. First, the paper analyzed the structure of ETC transaction data and presented the data preprocess procedure. Then, a dual-level travel speed calculation model was established under different levels of sample sizes. In order to ensure a sufficient sample size, ETC data of different enter-leave toll plazas pairs which contain more than one road segment were used to calculate the travel speed of every road segment. The reduction coefficient α and reliable weight θ for sample vehicle speed were introduced in the model. Finally, the model was verified by the special designed field experiments which were conducted on several freeways in Beijing at different time periods. The experiments results demonstrated that the average relative error was about 6.5% which means that the freeway travel speed could be estimated by the proposed model accurately. The proposed model is helpful to promote the level of the freeway operation monitoring and the freeway management, as well as to provide useful information for the freeway travelers.

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Related in: MedlinePlus

The diagram of relationship between road segments and OD pairs.
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fig2: The diagram of relationship between road segments and OD pairs.

Mentions: The study found that traffic flow operation states of the adjacent road segments had a strong correlation, and the relationship between them was rather steady (Figure 2). Therefore, reduction coefficient for OD speed was introduced in the models which can be obtained by analyzing relationship of historical traffic flow. First, the study calculated the travel speed of OD pair and the corresponding road segment based on the historical data. Then, speed reduction coefficient was the ratio of OD speed to road speed, and calculation formula should be(2)αz=VODjZVj,where αz is the reduction coefficient for OD pair z  speed to speed of road segment  j; Vj is historical travel speed for the road segment j; vODijz is the average travel speed of the vehicle with the OD pair z containing j segment, z = 1,2,…, z,  where  z is number of OD when sample size of road segment is deficient.


Freeway travel speed calculation model based on ETC transaction data.

Weng J, Yuan R, Wang R, Wang C - Comput Intell Neurosci (2014)

The diagram of relationship between road segments and OD pairs.
© Copyright Policy
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4279848&req=5

fig2: The diagram of relationship between road segments and OD pairs.
Mentions: The study found that traffic flow operation states of the adjacent road segments had a strong correlation, and the relationship between them was rather steady (Figure 2). Therefore, reduction coefficient for OD speed was introduced in the models which can be obtained by analyzing relationship of historical traffic flow. First, the study calculated the travel speed of OD pair and the corresponding road segment based on the historical data. Then, speed reduction coefficient was the ratio of OD speed to road speed, and calculation formula should be(2)αz=VODjZVj,where αz is the reduction coefficient for OD pair z  speed to speed of road segment  j; Vj is historical travel speed for the road segment j; vODijz is the average travel speed of the vehicle with the OD pair z containing j segment, z = 1,2,…, z,  where  z is number of OD when sample size of road segment is deficient.

Bottom Line: The reduction coefficient α and reliable weight θ for sample vehicle speed were introduced in the model.The experiments results demonstrated that the average relative error was about 6.5% which means that the freeway travel speed could be estimated by the proposed model accurately.The proposed model is helpful to promote the level of the freeway operation monitoring and the freeway management, as well as to provide useful information for the freeway travelers.

View Article: PubMed Central - PubMed

Affiliation: Beijing Key Laboratory of Traffic Engineering, Beijing University of Technology, Beijing 100124, China.

ABSTRACT
Real-time traffic flow operation condition of freeway gradually becomes the critical information for the freeway users and managers. In fact, electronic toll collection (ETC) transaction data effectively records operational information of vehicles on freeway, which provides a new method to estimate the travel speed of freeway. First, the paper analyzed the structure of ETC transaction data and presented the data preprocess procedure. Then, a dual-level travel speed calculation model was established under different levels of sample sizes. In order to ensure a sufficient sample size, ETC data of different enter-leave toll plazas pairs which contain more than one road segment were used to calculate the travel speed of every road segment. The reduction coefficient α and reliable weight θ for sample vehicle speed were introduced in the model. Finally, the model was verified by the special designed field experiments which were conducted on several freeways in Beijing at different time periods. The experiments results demonstrated that the average relative error was about 6.5% which means that the freeway travel speed could be estimated by the proposed model accurately. The proposed model is helpful to promote the level of the freeway operation monitoring and the freeway management, as well as to provide useful information for the freeway travelers.

Show MeSH
Related in: MedlinePlus