Vehicle-Type Specific Headway Distribution in Freeway Work Zones: A Nonparametric Approach

Vehicle Headway is critical to traffic flow control and operation. Significant research has been conducted on this topic. Previous work focused primarily on parametric models which are based on certain assumptions, thus its reliability is still debated. This paper employs a nonparametric distribution model with Gaussian kernel functions to investigate freeway work zone scenarios. Without prior assumptions of the possible distribution model, a Gaussian kernel model is capable of capturing the intrinsic features from empirical work zone headway data to describe the headway distribution. The nonparametric model would be more favorable in various scenarios. In addition, this paper aims on the vehicle-type specific model: car-car, car-van, car-truck, van-car, van-van, van-truck, truck-car, truck-van, and truck-truck. The K-S test confirmed the performance of the nonparametric model. All K-S statistics indicate that the non-parametric model with Gaussian kernel model outperforms parametric models such as the lognormal distribution. Experiments were further conducted on the nine types of headways to provide visual evidence. The Gaussian kernel model shows robust capability in describing the probability density function and cumulative density function, the relative error is rather small and can be considered to be negligible. The lognormal distribution is compared against the Gaussian kernel model when fitting the empirical headway data. The results show Gaussian kernel model performs better in approximating empirical headway data in work zones. As a result, the relative error is consistently smaller than the lognormal distribution which has a large initial fluctuation. The results suggest that the nonparametric distribution model with Gaussian kernel functions has a better goodness-of-fit in the vehicle-type specific work zone scenario.

• Supplemental Notes:
  • This paper was sponsored by TRB committee AHB55 Work Zone Traffic Control.
• Corporate Authors:

  Transportation Research Board

  500 Fifth Street, NW
  Washington, DC  United States  20001
• Authors:
  • Dong, Shangjia
  • Wang, Haizhong
  • Hurwitz, David
  • 0000-0001-8450-6516
  • Heaslip, Kevin
• Conference:
  • Transportation Research Board 93rd Annual Meeting
  • Location: Washington DC
  • Date: 2014-1-12 to 2014-1-16
• Date: 2014

Language

• English

Media Info

• Media Type: Digital/other
• Features: Figures; References; Tables;
• Pagination: 19p
• Monograph Title: TRB 93rd Annual Meeting Compendium of Papers

Subject/Index Terms

• TRT Terms: Freeways; Headways; Nonparametric analysis; Work zone traffic control; Work zones
• Subject Areas: Construction; Highways; Operations and Traffic Management; I50: Construction and Supervision of Construction; I73: Traffic Control;

Filing Info

• Accession Number: 01520733
• Record Type: Publication
• Report/Paper Numbers: 14-4355
• Files: TRIS, TRB, ATRI
• Created Date: Mar 31 2014 3:03PM