scholarly journals Developing a Traffic Management Framework for Coastal Expressway Bridges under Adverse Weather Conditions: Case Study of Rain Day in Shenzhen, China

2015 ◽  
Vol 2015 ◽  
pp. 1-11 ◽  
Author(s):  
Chenming Jiang ◽  
Jian John Lu ◽  
Yuming Jiang ◽  
Xiaonan Cai ◽  
Anning Ni
Keyword(s):  
Traffic Management ◽  
Injury Severity ◽  
Control Strategies ◽  
Geographical Location ◽  
Surface Friction ◽  
Weather Conditions ◽  
Negative Influence ◽  
Management Framework ◽  
Adverse Weather ◽  
Alternate Routes

Adverse weather can reduce visibility and road surface friction, lower vehicle maneuverability, and increase crash frequency and injury severity. The impacts of adverse weather and its interactions with drivers and roadway on the operation and management of expressway or expressway bridges have drawn the researchers’ and managers’ attention to develop traffic management frameworks to mitigate the negative influence. Considering the peculiar geographical location and meteorological conditions, the Guangshen Coast Expressway-Shenzhen Segment (GSCE-SS) was selected as a case in this study to illustrate the proposed traffic management framework on rain days. Conditions categorized by rainfall intensity and traffic flow were the main precondition to make the management decisions. CORSIM simulator was used to develop the alternate routes choice schemes, providing reference for other systems in the proposed traffic management framework. Maps of (a) entrance ramp control (ERC) strategies; (b) mainline control strategies; (c) alternate routes choice; (d) information release schemes, under scenarios of different volume and rainstorm warning grades (BLUE to RED), were drawn to present a reference or demonstration for managers of long-span expressway bridges not only in China, but even in the world.

scholarly journals Impacts of Snowy Weather Conditions on Expressway Traffic Flow Characteristics

2013 ◽  
Vol 2013 ◽  
pp. 1-6 ◽  
Author(s):  
Jiancheng Weng ◽  
Lili Liu ◽  
Jian Rong
Keyword(s):  
Traffic Flow ◽  
Traffic Management ◽  
Control Strategies ◽  
Flow Characteristics ◽  
Weather Conditions ◽  
Service Levels ◽  
The Road ◽  
Adverse Weather ◽  
Snow Conditions ◽  
The Impact

Snowy weather will significantly degrade expressway operations, reduce service levels, and increase driving difficulty. Furthermore, the impact of snow varies in different types of roads, diverse cities, and snow densities due to different driving behavior. Traffic flow parameters are essential to decide what should be appropriate for weather-related traffic management and control strategies. This paper takes Beijing as a case study and analyzes traffic flow data collected by detectors in expressways. By comparing the performance of traffic flow under normal and snowy weather conditions, this paper quantitatively describes the impact of adverse weather on expressway volume and average speeds. Results indicate that average speeds on the Beijing expressway under heavy snow conditions decrease by 10–20 km/h when compared to those under normal weather conditions, the vehicle headway generally increases by 2–4 seconds, and the road capacity drops by about 33%. This paper also develops a specific expressway traffic parameter reduction model which proposes reduction coefficients of expressway volumes and speeds under various snow density conditions in Beijing. The conclusions paper provide effective foundational parameters for urban expressway controls and traffic management under snow conditions.

Influence of weather on two insectivorous bats in a temperate Pacific Northwest rainforest

2009 ◽  
Vol 87 (2) ◽  
pp. 132-138 ◽  
Author(s):  
D. W. Burles ◽  
R. M. Brigham ◽  
R. A. Ring ◽  
T. E. Reimchen
Keyword(s):  
Reproductive Success ◽  
Pacific Northwest ◽  
Weather Conditions ◽  
Negative Influence ◽  
Myotis Lucifugus ◽  
Insectivorous Bats ◽  
Ambient Temperatures ◽  
The Pacific ◽  
Adverse Weather ◽  
Insect Activity

Adverse weather conditions frequently have a significant negative influence on survival and reproductive success of insectivorous bats. Low ambient temperatures increase the energetic costs of maintaining euthermia and reduces insect activity, while precipitation likely adds “clutter” making prey more difficult to detect using echolocation. We studied two species of insectivorous bats, Myotis lucifugus (LeConte, 1831) and Myotis keenii (Merriam, 1895), in the Pacific Northwest of Canada, a region that experiences frequent cool, wet weather during spring and summer. Our study took place during the El Niño – La Niña cycle of 1998–1999, which resulted in contrasting years. The summer of 1998 was unusually warm and dry, while the summer of 1999 was unusually cool and wet. We predicted that both species would be adversely affected by the cool, wet conditions of 1999, resulting in prolonged gestation, late fledging of young, and lower reproductive success. However, this was not the case. Myotis lucifugus did experience delays in reproductive timing and lower reproductive success in 1999, as predicted, whereas M. keenii experienced much shorter gestations, earlier fledgings, and no difference in reproductive success between years. We hypothesize that the ability of M. keenii to glean prey enables it to better cope with cool, wet conditions.

Predictive Time-Based Feedback Control Approach for Managing Freeway Incidents

2000 ◽  
Vol 1710 (1) ◽  
pp. 79-84 ◽  
Author(s):  
Omar B. Sawaya ◽  
Dung L. Doan ◽  
Athanasios K. Ziliaskopoulos
Keyword(s):  
Feedback Control ◽  
Traffic Management ◽  
Control Strategies ◽  
Compliance Rate ◽  
Dynamic Control ◽  
Route Guidance ◽  
Control Approach ◽  
Real Time Traffic ◽  
Freeway Incidents ◽  
Alternate Routes

A feedback control approach is introduced that produces dynamic control strategies in the form of alternate routes around freeway incidents and in response to the prevailing traffic conditions. The approach is based on the equalization of predictive travel times on alternate routes. The methodology is intended to be used as a decision-aid tool for real-time traffic management applications, more specifically for route guidance via variable message signs. The approach is implemented and tested computationally on an example network in a simulated environment under various scenarios of system disturbances. The results indicate that the performance of this approach is fairly robust to uncertainties in demand, compliance rate, and incident severity. It also performs better than an anticipatory approach and an instantaneous time–based feedback control approach.

Effectiveness of Predictive Weather-Related Active Transportation and Demand Management Strategies for Network Management

2017 ◽  
Vol 2667 (1) ◽  
pp. 71-87 ◽  
Author(s):  
Zihan Hong ◽  
Hani S. Mahmassani ◽  
Xiang Xu ◽  
Archak Mittal ◽  
Ying Chen ◽  
...  
Keyword(s):  
Traffic Management ◽  
Demand Management ◽  
Management Strategies ◽  
Weather Conditions ◽  
Active Transportation ◽  
Operational Conditions ◽  
Traffic Conditions ◽  
Adverse Weather ◽  
Traffic Performance ◽  
The Impact

This paper presents the development, implementation, and evaluation of predictive active transportation and demand management (ATDM) and weather-responsive traffic management (WRTM) strategies to support operations for weather-affected traffic conditions with traffic estimation and prediction system models. First, the problem is defined as a dynamic process of traffic system evolution under the impact of operational conditions and management strategies (interventions). A list of research questions to be addressed is provided. Second, a systematic framework for implementing and evaluating predictive weather-related ATDM strategies is illustrated. The framework consists of an offline model that simulates and evaluates the traffic operations and an online model that predicts traffic conditions and transits information to the offline model to generate or adjust traffic management strategies. Next, the detailed description and the logic design of ATDM and WRTM strategies to be evaluated are proposed. To determine effectiveness, the selection of strategy combination and sensitivity of operational features are assessed with a series of experiments implemented with a locally calibrated network in the Chicago, Illinois, area. The analysis results confirm the models’ ability to replicate observed traffic patterns and to evaluate the system performance across operational conditions. The results confirm the effectiveness of the predictive strategies tested in managing and improving traffic performance under adverse weather conditions. The results also verify that, with the appropriate operational settings and synergistic combination of strategies, weather-related ATDM strategies can generate maximal effectiveness to improve traffic performance.

Investigating the Temporal Instability in Injury Severity Outcomes of Clear and Adverse Weather Crashes on Rural Mountainous Highways

2021 ◽  
pp. 036119812110570
Author(s):  
Irfan U. Ahmed ◽  
Mohamed M. Ahmed
Keyword(s):  
Monte Carlo ◽  
Injury Severity ◽  
Statistical Significance ◽  
Weather Conditions ◽  
Warning Signs ◽  
Parameter Estimates ◽  
Connected Vehicle ◽  
Temporal Instability ◽  
Short Period ◽  
Adverse Weather

Analysis of driver injury severity based on weather conditions on rural highways is limited in the literature. Such analyses provide insights useful to policymakers in optimizing the allocation of limited resources based on weather conditions. Furthermore, if there is a possibility of factors exhibiting temporal instability, then an aggregate analysis can lead to erroneous allocation of funds. In this study, separate models for clear and adverse weather conditions were developed for each of the years from 2015 to 2019 using crash data from a rural mountainous highway corridor. A random-intercept Bayesian logistic approach was used to analyze the dichotomous injury severity response and capture the between-crash variance. An efficient Markov chain Monte Carlo sampling technique known as the No-U-Turn Hamiltonian Monte Carlo was employed to sample the posterior distributions of parameter estimates. Likelihood ratio tests provided statistical significance of the temporal instability and also the differences in driver injury severities resulting from clear and adverse weather crashes. While most of the variables demonstrated temporal instability, some factors exhibited temporal stability over a short period of time and only during clear weather conditions. Findings from the separate models suggest that there are major differences in both the combination and magnitude of the significant contributing factors. Implementation of confirmatory warning signs, variable message signs, connected vehicle technology, strict enforcements during different times and locations, and driver awareness programs have been recommended as suitable countermeasures. The findings and recommendations could potentially help in guiding the respective agencies in formulating injury severity mitigation policies and strategies.

scholarly journals The Management of Urban Freeway Traffic

1974 ◽  
Vol 1 (2) ◽  
pp. 141-149 ◽  
Author(s):  
Allen R. Cook
Keyword(s):  
Traffic Congestion ◽  
Urban Areas ◽  
Traffic Management ◽  
Control Strategies ◽  
False Alarms ◽  
Freeway Traffic ◽  
Detection Algorithms ◽  
Urban Freeway ◽  
And Control ◽  
Alternate Routes

The advent of computer-controlled electronic freeway surveillance and control systems in the past decade represents a potentially significant new operational tool for traffic engineers in large urban areas. These systems are capable of responding to rapidly changing traffic conditions and in various demonstration projects they have proven useful in maintaining an acceptable level of service for freeway operations, reducing the extent and duration of traffic congestion, minimizing the adverse effects of accidents and other incidents on traffic operations, and reducing accident experience. Surveillance system goals and techniques for achieving these goals are reviewed in this paper with particular emphasis on the problem of managing unexpected capacity-reducing incident situations. Recent research has demonstrated the feasibility of detecting incidents from traffic flow data, which is desirable for surveillance purposes because this information can be used to implement control strategies which attempt in real-time to divert some freeway traffic to alternate routes. Some of the operational problems involved with freeway traffic management are discussed, particularly the generation of false alarms by detection algorithms and driver willingness to be diverted to alternate routes.

THE GROWTH REGULATORS AND MICRONUTRIENTS ROLE UNDER THE HERBS INTRODUCTION IN TO CULTURE

1970 ◽  
pp. 62-66
Author(s):  
N. I. Sidelnikov ◽  
N. I. Kovalev ◽  
F. M. Khazieva
Keyword(s):  
Powdery Mildew ◽  
Medicinal Plants ◽  
Growth Regulator ◽  
Crop Yields ◽  
Negative Impact ◽  
Raw Materials ◽  
Weather Conditions ◽  
Negative Influence ◽  
Serratula Coronata ◽  
Adverse Weather

With the introduction of new species of medicinal plants there is a change in their usual ecological condition. Unstable weather conditions and phytopathogens can have a negative influence on crop yields. In this article discussed some aspects exogeny management of adaptation processes for new introduced medicinal plants: Lycopus europaeus L., Arctium lappa L., Serratula coronata L. Application of plant growth regulator Dvau for rooting cuttings and binary mixtures of growth regulator Zircon and organomineral (Absolute,Ecofus) or silicon fertilizers (Siliplant) in fields on gypsywort  promotes resistance to adverse weather conditions and reduced crop losses in low moisture and high temperatures of 16-20%, with high humidity and low temperature – 23-25%. On greater burdock it is shown that insufficient water supply has a negative impact on growth processes: the area of the assimilating surface of plants decreases by 17%, the mass of roots - by 13%. Double treatment of plants with silicon-containing microfertilizer Siliplant eliminates the negative impact of drought and increases the yield of roots (medicinal raw materials) by 17-18%. Abiotic and biotic stresses can have a negative impact on the yield and quality of medicinal raw materials of Serratula coronata. Application of microfertilizer Ferovit in dry weather conditions increases the area of the assimilating surface by 28-30%, the yield of raw materials (grass) by 20-25%. One of the biotic stress on Serratulais is the defeat of plants by powdery mildew (Erysiphe cichoracearum D.C.). Complex application of the growth regulator Zircon and microfertilizer Ferovit provided a more rapid passing of phenological stages, which allowed to begin the harvest before plants defeat by powdery mildew and to exclude from the agrotechnology the use of fungicides.

Role of Adverse Weather in Key Crash Types on Limited-Access: Roadways Implications for Advanced Weather Systems

1998 ◽  
Vol 1621 (1) ◽  
pp. 10-19 ◽  
Author(s):  
Asad J. Khattak ◽  
Paula Kantor ◽  
Forrest M. Council
Keyword(s):  
Injury Severity ◽  
Safety Information ◽  
Surface Friction ◽  
Crash Risk ◽  
Limited Access ◽  
Probit Models ◽  
Adverse Weather ◽  
Single Vehicle ◽  
Ordered Probit Models ◽  
Crash Types

Adverse weather can reduce visibility and road surface friction and thus increase crash frequency and injury severity. However, drivers may compensate for higher crash risk by reducing speeds, maintaining safe spacing, and driving more carefully. The impacts of adverse weather and its interactions with driver and roadway characteristics on the occurrence and injury severity of selected crash types are analyzed. Single-vehicle, two-vehicle sideswipe, and two-vehicle rear-end collisions on limited-access roadways are considered. To analyze differential impacts of adverse weather on crash type, binary probit models are estimated for single-vehicle versus the two types of two-vehicle crashes, and for rear-ends versus sideswipes. To analyze injury severity, ordered probit models are estimated. The 1990–1995 Highway Safety Information System (HSIS) database for North Carolina was used for analysis. The results indicate that, for the selected crash types, drivers appear to compensate for increased injury risks in that in adverse weather crashes are more frequent but injuries are less severe. Some implications for advanced weather systems are discussed.

scholarly journals Driver Preference and Level of Trust Related to Real-Time Road Freezing Risk Information

2020 ◽  
Vol 2020 ◽  
pp. 1-11
Author(s):  
Moataz Bellah Ben Khedher ◽  
Choong Heon Yang ◽  
Jin Guk Kim ◽  
Duk Geun Yun ◽  
Sung Pil Shin
Keyword(s):  
Real Time ◽  
Information Service ◽  
Winter Season ◽  
Surface Friction ◽  
Weather Conditions ◽  
Risk Information ◽  
Navigation Systems ◽  
Adverse Weather ◽  
Driver's License ◽  
Bad Weather

Bad weather conditions can affect normal driving by substantially hindering visibility. Among all adverse weather conditions, road freezing is probably the most dangerous to drivers because slippery roads reduce surface friction and can lead to loss of vehicle control. This paper evaluates driver preference of receiving real-time road freezing risk information and explores the factors that would most influence drivers’ trust in a future road freezing information service. A survey was conducted in the metropolitan areas of South Korea during January and February 2019. The survey was completed by 231 driver’s license holders of 18 years or older, and the results were used for statistical analysis. According to the survey results, the variable message sign (VMS) is a very important system from the perspective of public benefit. Car-navigation systems are preferred for age categories of 21∼30 and over 50. In addition, ordinal regression was used to analyze the causal relationship between the level of trust regarding road freezing risk information and its controlling factors. The ordered log odds of drivers with previous accident experience due to slippery roads exhibit a higher level of trust in road freezing risk information because the coefficient is positive. Moreover, drivers with a constant commute time show a lower level of trust in road freezing risk information. These findings provide a foundation for planning the scope of future road freezing risk information service, as well as the specific service targets and type of information, especially during the winter season.

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