scholarly journals A signal timing assignment proposal for urban multi lane signalised roundabouts

2019 ◽  
Vol 71 (2) ◽  
pp. 113-124 ◽  
Author(s):  
Yetis Sazi Murat ◽  
Ziya Cakici ◽  
Zong Tian
Keyword(s):  
Traffic Volume ◽  
Calculation Procedure ◽  
Signal Timing ◽  
Expression Model ◽  
Storage Area ◽  
The Relationship

The relationship between the left-turning traffic volume and the storage area at signalised roundabouts is investigated, and a calculation procedure for signal timing is proposed in this paper. The parameters associated with the developing stages of a new expression/model are also defined. Four different signal timing scenarios are considered. The results show that the proposed formula can be used for the design of signalised roundabouts.

Relationship Between Volume-to-Capacity Ratios and Accident Rates

1997 ◽  
Vol 1581 (1) ◽  
pp. 47-52 ◽  
Author(s):  
Min Zhou ◽  
Virginia P. Sisiopiku
Keyword(s):  
Traffic Volume ◽  
The Other ◽  
Explanatory Factors ◽  
Traffic Conflict ◽  
Single Vehicle ◽  
Driver Inattention ◽  
Detroit Area ◽  
Accident Rates ◽  
The Relationship ◽  
Shaped Pattern

The general relationships between hourly accident rates and hourly traffic volume/capacity ( v/c) ratios were examined. A 26 km (16 mi) segment of Interstate I-94 in the Detroit area was selected as the study segment. The v/c ratios were calculated from average hourly traffic volume counts collected in 1993 and 1994 from three permanent count stations. Accident rates were derived from hourly distributed number of accidents in the same 2 years. The correlation between v/c values and accident rates follows a general U-shaped pattern. The study of all observed accidents combined indicates that accident rates are highest in the very low hourly v/c range, decrease rapidly with increasing v/c ratio, and then gradually increase as the v/c ratio continues to increase. U-shaped models also explain the relationship between v/c and accident rates for weekdays and weekend days, multivehicle, rear-end, and property-damage-only accidents. On the other hand, single-vehicle, fixed-object, and turnover accidents, and accidents involving injury and fatality follow a generally decreasing trend with increasing v/c ratio. Traffic conflict is viewed as a major contributing factor to high accident rates observed in the high v/c range, whereas night conditions and driver inattention were identified as explanatory factors for the occurrence of high accident rates in the low v/c ranges.

Dynamic User Optimal of Traffic Assignment Based on Optimal Signal Timing

2014 ◽  
Vol 587-589 ◽  
pp. 2040-2044
Author(s):  
Lu Zhang
Keyword(s):  
Variational Inequality ◽  
Network Performance ◽  
Traffic Assignment ◽  
Dynamic Traffic Assignment ◽  
Equivalent Model ◽  
Signal Timing ◽  
Optimal Model ◽  
Dynamic Traffic ◽  
The Relationship ◽  
Optimal Signal

At the beginning the paper summarizes the research status,models and algorithms of dynamic traffic assignment and analyzes the relationship between dynamic user optimal model and variational inequality.Secondly,a dynamic user optimal model of traffic assignment based on optimal signal timing is established,equivalent model of the variational inequality is built at the same time.Finally,we discuss the superiority of the model and apply this model to a simple example,the results show that the model can improve the network performance significantly.

scholarly journals The impact of different saturation headway values on intersection capacity

2021 ◽  
Author(s):  
Dražen Cvitanić ◽  
Biljana Maljković
Keyword(s):  
Traffic Flow ◽  
Flow Structure ◽  
Road Network ◽  
Weather Conditions ◽  
Traffic Volume ◽  
Signalized Intersections ◽  
Signal Timing ◽  
Bad Weather ◽  
The Impact ◽  
The City

Elements of the city road network that determine its capacity are signalized intersections. Their capacity depends of many factors: traffic volume and distribution, traffic flow structure, signal timing, and number of bicyclists and pedestrians. However, the starting parameter for calculation of intersection capacity is saturation headway. This research explores the influence of weather conditions and purpose of trip on saturation headway. Saturation headways were determined on few intersections in the morning peak hour of working and weekend day, in good and bad weather conditions. The impact of different trip purposes and different weather conditions on intersection capacity is analysed, as well as the influence of using mean and median values of saturation headway when calculating the intersection capacity.

scholarly journals Elevated wildlife-vehicle collision rates during the COVID-19 pandemic

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Joel O. Abraham ◽  
Matthew A. Mumma
Keyword(s):  
United States ◽  
The United States ◽  
Traffic Volume ◽  
Vehicle Collisions ◽  
Vehicle Collision ◽  
The Relationship

AbstractWildlife-vehicle collisions threaten both humans and wildlife, but we still lack information about the relationship between traffic volume and wildlife-vehicle collisions. The COVID-19 pandemic allowed us to investigate the effects of traffic volume on wildlife-vehicle collisions in the United States. We observed decreased traffic nationwide, particularly in densely populated states with low or high disease burdens. Despite reduced traffic, total collisions were unchanged; wildlife-vehicle collisions did decline at the start of the pandemic, but increased as the pandemic progressed, ultimately exceeding collisions in the previous year. As a result, nationwide collision rates were higher during the pandemic. We suggest that increased wildlife road use offsets the effects of decreased traffic volume on wildlife-vehicle collisions. Thus, decreased traffic volume will not always reduce wildlife-vehicle collisions.

scholarly journals Research on Truck Traffic Volume Conditions of Auxiliary Lanes on Two-Lane Highways

2021 ◽  
Vol 13 (23) ◽  
pp. 13097
Author(s):  
Guozhu Cheng ◽  
Changru Mu ◽  
Liang Xu ◽  
Xuejian Kang
Keyword(s):  
Evaluation Method ◽  
Traffic Volume ◽  
Truck Traffic ◽  
Time Model ◽  
Traffic Efficiency ◽  
Vehicle Test ◽  
Design Speed ◽  
Auxiliary Lanes ◽  
The Impact ◽  
The Relationship

The larger the proportion of truck traffic volume, the greater the impact on traffic efficiency, and overtaking behavior will also have an impact. Therefore, in order to clarify the truck traffic volume of the freight two-lane highway due to the difficulty of overtaking, an actual vehicle test is carried out. This involves selecting the appropriate two-lane test section, recording each moment and speed in the driver’s overtaking behavior, performing multiple regression analysis to examine the relationship between the overtaking conflict time and design speed and traffic volume, determining a reasonable evaluation series of two-lane road overtaking risk and the corresponding overtaking conflict time threshold by the Fisher optimal segmentation method, and giving an overtaking behavior risk evaluation method based on conflict time. Finally, according to the overtaking conflict time model, different truck traffic conditions are obtained. The research results show that overtaking conflict time is negatively correlated with the traffic volume and design speed of the lane. Through the risk assessment of the corresponding overtaking behavior, the three levels of serious conflict, general conflict and non-conflict are determined, and the freight traffic volume corresponding to different conflict levels at different speeds is calculated, which provides a reference for setting auxiliary lanes for the two-lane freight highway.

scholarly journals MORE TRAFFIC MEANS MORE ACCIDENTS? THE CASE OF FRENCH NICE HIGHWAY

2020 ◽  
Vol XLIV-4/W2-2020 ◽  
pp. 25-27
Author(s):  
D. Grimaldi
Keyword(s):  
Large Volume ◽  
Road Traffic ◽  
Smart Cities ◽  
Traffic Volume ◽  
City Managers ◽  
Long Period ◽  
National Road ◽  
The Relationship ◽  
The City ◽  
No2 Pollution

Abstract. This paper argues the relationship between traffic volume and accidents in highway sections. The paper shows the French city of Nice case and the analysis of the M6098 highway connecting the city to the airport. Amongst the different variables that are linked to traffic volume we select, explaining our choice, the NO2 pollution parameter. We collect a large volume of data from a long period of time between 2012 and 2014 that we collect from the national road traffic center. Our results show it does exist a relationship between traffic volume and accidents with a stronger factor during the weekdays. A long debate exists in the Literature concerning this possible correlation and our paper suggests the confirmation for one of the different positions expressed. Our conclusions help city Managers in their task to understand the conditions of urban living and transport. They are additional inputs to define local policies in order to improve the efficiency of private transport and prepare future smart cities.

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