scholarly journals Multi-fidelity algorithms for the horizontal alignment problem in road design

2019 ◽  
Vol 52 (11) ◽  
pp. 1848-1867 ◽  
Author(s):  
Mahdi Aziz ◽  
Warren Hare ◽  
Majid Jaberipour ◽  
Yves Lucet
Keyword(s):  
Horizontal Alignment ◽  
Road Design ◽  
Alignment Problem

scholarly journals Horizontal Alignment Security Design Theory and Application of Superhighways

2020 ◽  
Vol 12 (6) ◽  
pp. 2222 ◽  
Author(s):  
Yu-Long Pei ◽  
Yong-Ming He ◽  
Bin Ran ◽  
Jia Kang ◽  
Yu-Ting Song
Keyword(s):  
Design Theory ◽  
Construction Technology ◽  
Security Design ◽  
Operating Characteristics ◽  
Highway Design ◽  
Vehicle Performance ◽  
Horizontal Alignment ◽  
Road Design ◽  
Design Speed ◽  
Circular Curves

In China, the maximum design speed of highways is 120 km/h, which first appeared in the Highway Engineering Technical Standard (Trial) in 1951. However, vehicle performance, road design, and construction technology have been greatly improved over the past 68 years. To adapt to the development demands of highway design speeds above 120 km/h in the future, it is urgent to study superhighway alignment design theory. Therefore, the horizontal alignment security design theory of superhighways was developed in this paper. First, the definition, classification, and construction mode of a superhighway and suitable vehicles of different grades are presented. Then, the lengths of straight lines were limited to reduce driving fatigue. Next, the minimum radii of circular curves were calculated based on driver characteristics and stress analysis of operating vehicles. Finally, the minimum lengths of transition curves were calculated based on the centrifugal acceleration of the operating vehicles, the travel time, and the passenger visual characteristics. The calculation and analysis results show that the superhighway linear features conform to the vehicle operating characteristics, and can ensure the safety of driving.

Evaluation of design consistency on horizontal curves for two-lane state roads using bicycle-model and realistic parameters of driver behaviour

2021 ◽  
Author(s):  
◽  
Biljana Maljković
Keyword(s):  
Point Mass ◽  
Horizontal Curve ◽  
Vehicle Model ◽  
Mass Model ◽  
Driver Behaviour ◽  
Horizontal Alignment ◽  
Horizontal Curves ◽  
Road Design ◽  
Vehicle Path ◽  
Design Consistency

The loss of vehicle stability in horizontal curves is a clear indicator of horizontal alignment design inconsistency, which can easily be quantified by determining the margins of safety. The doctoral thesis presents an overview of current horizontal alignment design guidelines and most important research of the design consistency concept. The following significant shortcomings in current road design practice were noticed: selection of unrealistic relevant speeds, the assumption that drivers follow a path with a radius equal to curve radius and the application of too simple vehicle model, i.e. basic point mass model. To overcome the observed limitations, the new consistent design approach has been developed, with an emphasis on horizontal curves. The new approach is based on the margin of safety concept, improved in terms of using the bicycle vehicle model in combination with more realistic values of speed and vehicle path radii. The bicycle vehicle model considers longitudinal load transfer, on individual axles, due to grade and speed changes, i.e. factors affecting margins of safety that are completely ignored by the simple point mass model used so far. To collect the driver behaviour data, an experimental investigation was conducted on a segment of the two-lane state road DC1 (Croatia). Individual speeds and vehicle path radii achieved by representative sample of drivers were recorded with a highfrequency GPS device. Based on the analysis of recorded data, the implementation of naturalistic driver behaviour in the road design process is proposed through regression models for predicting operating speeds (for tangents and horizontal curves) and through the equation for calculating the critical path radius. The improvement of the safety margin concept has created the basis for designing horizontal curves with high level of safety, both for the values of available friction on modern pavements as well as for future measurements. Based on operating speed consistency criterion and improved safety criterion related to driving dynamic consistency, the graphs of applicable adjacent horizontal curve radii were developed. The results obtained showed that the values of minimum horizontal curve radii need to be increased and, finally, this analysis has provided a physical explanation of the most common causes of accidents in sharp horizontal curves.

Optimization of horizontal alignment geometry in road design and reconstruction

2017 ◽  
Vol 74 ◽  
pp. 261-274 ◽  
Author(s):  
Gerardo Casal ◽  
Duarte Santamarina ◽  
Miguel E. Vázquez-Méndez
Keyword(s):  
Horizontal Alignment ◽  
Road Design

scholarly journals Perencanaan Geometri Jalan Berdasarkan Metode Bina Marga Menggunakan Program Visual Basic

2011 ◽  
Vol 2 (1) ◽  
pp. 325
Author(s):  
Eduardi Prahara
Keyword(s):  
Highway Construction ◽  
Visual Basic ◽  
Geometric Design ◽  
Vertical Alignment ◽  
Low Speed ◽  
Horizontal Alignment ◽  
The Road ◽  
Road Design ◽  
Manual Calculation

One of the main things in a highway construction plan is the geometric design that includes horizontal and vertical alignment design. This study aims to formulate the steps of highway geometric design into Visual Basic 2005 program. The design steps are the calculation of horizontal and vertical alignment. Using Visual Basic 2005, it is expected that the calculation can be done faster than the manual calculation without mistake. The program is validated by comparing results obtained by manual calculations with a difference about 1x10-4 which is considered accurate. As a case study, a geometric road design is conducted in Bogor in 2009 with a fairly low-speed plan 20-40 km/hour. In the plan, the road has 28 PI (Points of Intersection) on the horizontal alignment and 15 PVI (Point of Vertical Intersection) and obtains good results in accordance with requirements and regulations issued by Bina Marga. 

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 Integrated Double-Sided Random Microlens Array Used for Laser Beam Homogenization

Micromachines ◽  
2021 ◽  
Vol 12 (6) ◽  
pp. 673
Author(s):  
Wei Yuan ◽  
Cheng Xu ◽  
Li Xue ◽  
Hui Pang ◽  
Axiu Cao ◽  
...  
Keyword(s):  
Laser Beam ◽  
Microlens Array ◽  
Energy Utilization ◽  
Utilization Rate ◽  
Periodic Lattice ◽  
Lattice Distribution ◽  
Speckle Field ◽  
High Laser ◽  
Alignment Problem ◽  
In Series

Double microlens arrays (MLAs) in series can be used to divide and superpose laser beam so as to achieve a homogenized spot. However, for laser beam homogenization with high coherence, the periodic lattice distribution in the homogenized spot will be generated due to the periodicity of the traditional MLA, which greatly reduces the uniformity of the homogenized spot. To solve this problem, a monolithic and highly integrated double-sided random microlens array (D-rMLA) is proposed for the purpose of achieving laser beam homogenization. The periodicity of the MLA is disturbed by the closely arranged microlens structures with random apertures. And the random speckle field is achieved to improve the uniformity of the homogenized spot by the superposition of the divided sub-beams. In addition, the double-sided exposure technique is proposed to prepare the rMLA on both sides of the same substrate with high precision alignment to form an integrated D-rMLA structure, which avoids the strict alignment problem in the installation process of traditional discrete MLAs. Then the laser beam homogenization experiments have been carried out by using the prepared D-rMLA structure. The laser beam homogenized spots of different wavelengths have been tested, including the wavelengths of 650 nm (R), 532 nm (G), and 405 nm (B). The experimental results show that the uniformity of the RGB homogenized spots is about 91%, 89%, and 90%. And the energy utilization rate is about 89%, 87%, 86%, respectively. Hence, the prepared structure has high laser beam homogenization ability and energy utilization rate, which is suitable for wide wavelength regime.

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