Two-Way Left Turn Lane or Raised Median? A Truck Safety Based Study

Due to their size and weight, trucks require more space and time to make left turns when exiting or entering a roadway. Therefore, appropriate median treatments are critical for roadways with substantial truck traffic. The two-way left-turn lane (TWLTL) and raised median (RM) are the two types of median most commonly used to improve roadway mobility and manage roadway accessibility. However, previous studies on these median treatments have focused primarily on the general traffic conditions and geometric roadway features without considering their impacts on truck safety. To address this gap, this study investigates the safety impacts of TWLTL and RM by considering two major influencing factors - truck percentage and roadway access point density. First, a negative binomial regression is developed to analyze the relationship between crash frequency and various influencing factors. Next, a change point analysis is conducted to identify critical points for these two factors. The findings indicate that, compared with RM, TWLTL has significantly higher crash frequency, especially for roadways with a higher percentage of trucks. This suggests that the percentage of trucks should be taken into consideration when selecting an appropriate type of roadway median.

• Supplemental Notes:
  • This paper was sponsored by TRB committee ANB70 Standing Committee on Truck and Bus Safety.
• Corporate Authors:

  Transportation Research Board

  ,    
• Authors:
  • Qu, Wenrui
  • Tao, Tao
  • Zhao, Qun
  • Sun, Qiao
  • Qi, Yi
• Conference:
  • Transportation Research Board 98th Annual Meeting
  • Location: Washington DC, United States
  • Date: 2019-1-13 to 2019-1-17
• Date: 2019

Language

• English

Media Info

• Media Type: Digital/other
• Features: Maps; References; Tables;
• Pagination: 5p

Subject/Index Terms

• TRT Terms: Highway design; Medians; Safety analysis; Truck crashes; Truck traffic; Trucking safety; Two way left turn lanes; Vehicle mix
• Subject Areas: Design; Highways; Motor Carriers; Safety and Human Factors; Vehicles and Equipment;

Filing Info

• Accession Number: 01697686
• Record Type: Publication
• Report/Paper Numbers: 19-04386
• Files: TRIS, TRB, ATRI
• Created Date: Mar 1 2019 3:51PM