Impact of Part-Time Shoulder Use on Safety through the Highway Safety Manual

Coffey, Sean; Park, Sehhoon

doi:10.1061/9780784481530.018

Cited by 1 publication

(3 citation statements)

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“…On four-lane highways in both directions, the left hard shoulder width is typically 1.22 m (4 feet) to 2.44 m (8 feet). For highways with six or more lanes in both directions, the left-side hard shoulder width is also designed to be at least 3.048 m (10 ft), and when the truck hour traffic volume exceeds 250 vehicles, the shoulder width should preferably be 3.66 m [4,7]. China's highway code provisions for converting and expanding into eight or more lanes are not mandatory [5].…”

Section: Literature Review 21 Study Of Left Hard Shoulder On Highwaymentioning

confidence: 99%

“…In addition, the role and influence of highway shoulders were studied in Ref. [7], and the factors that have the greatest influence on the occurrence of lane change accidents when the left hard shoulder is set were screened in Ref. [45].…”

Section: Theoretical and Practical Applicationsmentioning

confidence: 99%

“…According to Ref. [7], The setting of highway shoulders will have an impact on traffic flow and road alignment. Lin [45] screened out the factors that have the greatest impact on highway vehicle safety before and after the installation of the hard shoulder on the left side.…”

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confidence: 99%

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Research on the Safety of the Left Hard Shoulder in a Multi-Lane Highway Based on Safety Performance Function

Zhao

et al. 2022

Sustainability

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The left hard shoulder plays an important role in the event of an emergency on the inside of a multi-lane highway, but past studies have not been able to clarify the criteria for its installation or quantify the safety impact of its installation on the left side. In order to study the influence of the left hard shoulder on the safety of vehicles traveling on multi-lane highways, based on past studies that only studied the situation of four-lane highways, this paper firstly constructs a multi-lane highway simulation model under different numbers of lanes based on the VISSIM traffic simulation and uses Surrogate Safety Assessment Model (SSAM) to study the conflict characteristics of multi-lane highway vehicles under different numbers of lanes. Based on the above findings, this paper introduces the Safety Performance Function (SPF) to construct a multi-lane freeway accident prediction model, calibrates the model by adding the indexes affected by the left side hard shoulder to the basic prediction mode, and uses the historical accident data of the Badou-Shihu section of the Guangdong Northern Second Ring Highway as the basis to study the differences in accident rates of the investigated section before and after setting the left hard shoulder. The study showed that the average Time to Collision (TTC) increased by 57.2%, Maximum Deceleration (MaxD) increased by 19.2%, and Delta Speed (DeltaS) increased by 15.3% after setting hard shoulders on the left side of multi-lane freeways, and traffic conflicts on multi-lane freeways were significantly reduced, and safety was improved considerably. In addition, the rear-end conflict rate decreased by 0.17%, 0.75%, and 4.6% after setting hard shoulders on the left side of one-way three, four, and five lanes, respectively, indicating that hard shoulders on the left side are the most effective in improving the safety of one-way five-lane freeways. The accident prediction results show that within the reasonable setting range of the left hard shoulder width (0~4 m), the accident rate decreases by about 1.5% for every 0.5 m increase if only the influence of the left hard shoulder width is considered. Without considering other factors, increasing the width of the hard shoulder on the left side can reduce the number of accidents. This indicates a significant safety improvement for a one-way five-lane highway after setting the hard shoulder on the left side, and the conclusion is consistent with the simulation results. In this paper, based on past research, the research object is extended to one-way three-, four-, and five-lane highways. The findings of this paper can help the road authorities develop specifications for installing hard shoulders on the left side of multi-lane freeways and adopt strategies to improve the traffic safety level of multi-lane freeways. In addition, the models and methods used in this paper can also help build a framework for future intelligent networked vehicle avoidance systems and promote the development of intelligent networked technologies.

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Section: Literature Review 21 Study Of Left Hard Shoulder On Highwaymentioning

confidence: 99%

Section: Theoretical and Practical Applicationsmentioning

confidence: 99%