scholarly journals Cognitive Load Variability from Road Characteristics Should Influence a Safety Requirement for Vehicle Stopping Sight Distance

2019 ◽  
Vol 63 (1) ◽  
pp. 2129-2133
Author(s):  
Cody A. Pennetti ◽  
Kelsey Hollenback ◽  
Inki Kim ◽  
James H. Lambert
Keyword(s):  
Reaction Time ◽  
Weather Conditions ◽  
Design Standards ◽  
Road Design ◽  
Adverse Weather Conditions ◽  
Sight Distance ◽  
Adverse Weather ◽  
Road Geometry ◽  
Stopping Sight Distance ◽  
Road Characteristics

Current U.S. geometric road design standards are based on a prescribed value for a driver’s perception-reaction time (a constant value of 2.5 seconds), which represents the time necessary for a driver to safely stop the vehicle to avoid a crash (referred to as a stopping sight distance); however, these standards fail to consider how road complexity, driver risk perception, and visual stimuli can influence perception-reaction time. With over a million vehicle fatalities a year (WHO, n.d.), it is necessary to investigate methods of improving driver safety. The influence of road characteristics is considered with some road design policies, but not currently applied to stopping sight distance. This paper introduces theoretical considerations for increasing perception-reaction time (and thereby adjusting speed limits or road geometry) based on roadway complexity (volume of vehicles, road geometry, pedestrian crossings, frequency of adverse weather conditions, or other conditions).

Controlling Crest Vertical Curvature Rates Based on Variable Grade Stopping Sight Distance Calculation

2015 ◽  
Vol 2521 (1) ◽  
pp. 31-44
Author(s):  
Stergios Mavromatis ◽  
Nikiforos Stamatiadis ◽  
Basil Psarianos ◽  
George Yannis
Keyword(s):  
Design Parameters ◽  
Control Element ◽  
Mass Model ◽  
Road Design ◽  
Sight Distance ◽  
Wide Range ◽  
Significant Difference ◽  
Road Geometry ◽  
Stopping Sight Distance ◽  
Braking Process

Stopping sight distance (SSD) is a key control element that directly affects the suggested values of crucial road design parameters. Although there is a significant difference in SSD values between upgrades and downgrades, many design policies ignore the grade effect during vehicle braking on variable grades. Such a case occurs during the determination of crest vertical curvature rates in which the relevant SSD values are extracted assuming leveled road geometry. This paper investigates a possible deficiency of such an approach with regard to cases in which the length of the vertical curve exceeds the control SSD values. SSD calculation on variable grades during the braking process was addressed through a recently developed process that related the point mass model and the laws of mechanics. For a wide range of design speed values, charts illustrating the required SSDs were drawn as a function of negative ending grade values related to the control crest vertical curve rates adopted by AASHTO. The process revealed numerous SSD shortage areas for which revised crest vertical curvature rates were provided to grant SSD adequacy throughout the vehicles' braking process. This paper also aimed to provide designers with ready-to-use vertical design tools associated with amended vertical curvature rates to AASHTO's road functional classification as a function of the crest vertical curve's exit grade value.

Safety at Curves and Road Geometry Standards in Some European Countries

1996 ◽  
Vol 1523 (1) ◽  
pp. 99-106 ◽  
Author(s):  
Thierry Brenac
Keyword(s):  
Urban Areas ◽  
National Standards ◽  
European Countries ◽  
Design Standards ◽  
The Road ◽  
Horizontal Curves ◽  
Road Design ◽  
Road Geometry ◽  
Design Speed ◽  
Curve Geometry

This paper deals with safety at horizontal curves on two-lane roads outside urban areas and the way the road design standards of different European countries account for this safety aspect. After a review of some research results, the main aspects of curve geometry and the curve's place in the horizontal alignment are analyzed. The main conclusions are that the traditional design speed approach is insufficient and that formal complementary rules in road design standards, especially to improve compatibility between successive elements of the alignment, must be introduced. If such complementary rules already exist in some national standards, they are neither frequent nor homogeneous throughout the different countries, and it seems that they are not based on sufficiently developed knowledge.

scholarly journals Ship Handling in Unprotected Waters: A Review of New Technologies in Escort Tugs to Improve Safety

2021 ◽  
Vol 2 (1) ◽  
pp. 46-62
Author(s):  
Santiago Iglesias-Baniela ◽  
Juan Vinagre-Ríos ◽  
José M. Pérez-Canosa
Keyword(s):  
High Performance ◽  
New Technologies ◽  
Weather Conditions ◽  
Hull Form ◽  
Best Available Technologies ◽  
Adverse Weather Conditions ◽  
Adverse Weather ◽  
New Type ◽  
Technological Challenge ◽  
And Performance

It is a well-known fact that the 1989 Exxon Valdez disaster caused the escort towing of laden tankers in many coastal areas of the world to become compulsory. In order to implement a new type of escort towing, specially designed to be employed in very adverse weather conditions, considerable changes in the hull form of escort tugs had to be made to improve their stability and performance. Since traditional winch and ropes technologies were only effective in calm waters, tugs had to be fitted with new devices. These improvements allowed the remodeled tugs to counterbalance the strong forces generated by the maneuvers in open waters. The aim of this paper is to perform a comprehensive literature review of the new high-performance automatic dynamic winches. Furthermore, a thorough analysis of the best available technologies regarding towline, essential to properly exploit the new winches, will be carried out. Through this review, the way in which the escort towing industry has faced this technological challenge is shown.

Statistical analysis and critical review of navigational accidents in adverse weather conditions

2018 ◽  
Vol 163 ◽  
pp. 502-517 ◽  
Author(s):  
N.P. Ventikos ◽  
A.D. Papanikolaou ◽  
K. Louzis ◽  
A. Koimtzoglou
Keyword(s):  
Statistical Analysis ◽  
Critical Review ◽  
Weather Conditions ◽  
Adverse Weather Conditions ◽  
Adverse Weather

Gendered Experiences of Mobility

Transfers ◽  
2013 ◽  
Vol 3 (3) ◽  
pp. 79-98 ◽  
Author(s):  
Shahnaz Huq-Hussain ◽  
Umme Habiba
Keyword(s):  
Middle Class ◽  
Travel Behavior ◽  
Weather Conditions ◽  
Capital City ◽  
Mobility Patterns ◽  
Security Issues ◽  
Adverse Weather Conditions ◽  
Adverse Weather ◽  
The City ◽  
Detailed Picture

This article examines the travel behavior of middle-class women in Dhaka, the capital city of Bangladesh and one of the world's largest and most densely populated cities. In particular, we focus on women's use of non-motorized rickshaws to understand the constraints on mobility for women in Dhaka. Primary research, in the form of an empirical study that surveyed women in six neighborhoods of Dhaka, underpins our findings. Our quantitative and qualitative data presents a detailed picture of women's mobility through the city. We argue that although over 75 percent of women surveyed chose the rickshaw as their main vehicle for travel, they did so within a complex framework of limited transport options. Women's mobility patterns have been further complicated by government action to decrease congestion by banning rickshaws from major roads in the city. Our article highlights the constraints on mobility that middle-class women in Dhaka face including inadequate services, poorly maintained roads, adverse weather conditions, safety and security issues, and the difficulty of confronting traditional views of women in public arenas.

Sign in / Sign up

Export Citation Format

Share Document