| 1. |
- Abou-Senna, Hatem, et al.
(författare)
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A methodology to quantify pedestrian crash rates against statewide averages for roadways and intersections
- 2016
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Konferensbidrag (refereegranskat)abstract
- To date there are no clear or uniform standards for a method to measure pedestrian crash rates and compare it against a statewide average. In this paper, a novel methodology to measure pedestrian crash rates along roadways and intersections were quantified. The main objective is to identify critical pedestrian crash locations that are operating above its corresponding statewide average. It was crucial to address the pedestrian-vehicular conflict as the State of Florida currently tops the list in the “Dangerous by Design” report as having the highest four pedestrian incident locations in the Country. The main challenge was to identify a practical and correct exposure measure. In most cases, the exposure measure is either unavailable or can be obtained at a greater cost. The methods and procedures explained in this paper are considered detailed, practical and provide a broad depiction of the main factors that directly contribute to pedestrian crashes. The main parameters used in calculating pedestrian crash rates along roadways included functional classification, number of lanes, area type, AADT and the total length of the roadway category. Conversely, main parameters for computing pedestrian crash rates for intersections included daily pedestrian volumes, distance crossed and the AADT in addition to the number of pedestrian crashes either along the studied roadways or intersections. The pilot studies conducted for the roadways and intersections revealed several critical safety locations within District 5 when compared to the developed statewide average rates which required further investigation to identify main causes and emphasize mitigation improvements.
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| 2. |
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| 3. |
- Guan, Wei, et al.
(författare)
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Advanced Dynamic Simulations in Transportation
- 2015
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Ingår i: Discrete dynamics in nature and society. - : Hindawi Publishing Corporation. - 1026-0226 .- 1607-887X. ; 2015
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Tidskriftsartikel (refereegranskat)
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| 4. |
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| 5. |
- Wu, Jiawei, et al.
(författare)
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Pedestrian-vehicle conflict analysis at signalized intersections using micro-simulation
- 2016
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Konferensbidrag (refereegranskat)abstract
- The main goal of this study is to explore whether the VISSIM simulation model and Surrogate Safety Assessment Model (SSAM) can be used to provide the reasonable estimates for pedestrian-vehicle conflicts at signalized intersections. Two types of pedestrian-vehicle conflicts are discussed in this study, including vehicle-yield-pedestrian and pedestrian-yield-vehicle. A total of 42 hours videos were recorded at seven signalized intersections for field data collection. The calibrated and validated VISSIM model was used to generate pedestrian-vehicle conflicts and SSAM software was used to extract these conflicts by processing the vehicle trajectory file from the VISSIM model. The mean absolute percent error (MAPE) was used to determine the maximum TTC and PET thresholds for pedestrian-vehicle conflicts. The results showed that there was a best goodness-of-fit between simulated conflicts and observed conflicts when the maximum TTC threshold was set to be 2.7 and the maximum PET threshold was set to be 8. Moreover, the linear regression was developed to study the relationship between simulated conflicts from the micro-simulation and the observed conflicts from the field. The result indicated that there was a significant statistical relationship between the simulated conflicts and the observed conflicts. However, it was also found that the VISSIM model underestimated the pedestrian-vehicle conflicts. One possible reason was that the VISSIM simulation cannot generate the pedestrian-vehicle conflicts that involved the illegal pedestrian behaviors such as red light violation in the real world.
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| 6. |
- Zaidi, Zaier, et al.
(författare)
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Safety evaluation of work zone including its technologies using stochastic micro-simulation
- 2013
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Ingår i: Proceedings of the 16th International Conference Road Safety on Four Continents. - Linköping : Statens väg- och transportforskningsinstitut.
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Konferensbidrag (övrigt vetenskapligt/konstnärligt)abstract
- In recent years, there has been a considerable increase in the amount of construction work on the U.S. national highways, resulting in lane closure in work zone area, causing congestion with a high traffic demand. ITS-based technology such as dynamic lane merging and variable speed limits were adopted by several states to enhance both safety and mobility of roadway work zones. Dynamic lane merging (DLM) in its two main forms namely the early merge and the late merge was designed to advise drivers on definite merging locations. Variable speed limits (VSL) were introduced to work zones to decrease speed fluctuations and to smoothen traffic through work zones. Up to date, there are no studies that contrast standalone or a combination of ITS technologies to standard work zones under matching work zone settings. This study simulates a two-to-one work zone lane closure configuration in VISSIM under six different Maintenance of Traffic (MOT) plans. The first MOT consisted of the conventional plans used in Florida work zones, the second MOT consisted of a simplified dynamic early merging system (early SDLMS), the third MOT consisted of a simplified dynamic late merging systems (late SDLMS), the fourth MOT consisted appending a VSL to the conventional Florida MOT, the fifth MOT consisted of adding a VSL to the early SDLMS, and the sixth MOT consisted of adding a VSL to the late SDLMS. From the safety point of view, early and late SDLMS performed poorly as compared to VSL and Motorist Awareness System (MAS) when higher volumes were involved, but the addition of VSL improved their safety aspect by decreasing the speed variance of the vehicles traveling in both open and a closed lane. It was concluded that the passage of traffic through a work zone is made safer when a speed control is integrated to a dynamic merge system.
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