scholarly journals A Study for Distribution Methods Between Superelevation and Side Friction Factor Reflecting Ergonomic Characteristics by Increasing Design Speed

2013 ◽  
Vol 15 (3) ◽  
pp. 103-115
Author(s):  
Seungwon Jeong ◽  
Sangyoup Kim ◽  
Jaisung Choi ◽  
Hongjin Kim ◽  
Taeyoun Jang
Keyword(s):  
Friction Factor ◽  
Design Speed ◽  
Side Friction Factor ◽  
Side Friction

scholarly journals Fenomena Lalu Lintas Simpang Bersinyal di Kota Bekasi (Studi Kasus: Simpang Tol Bekasi Timur)

2016 ◽  
Vol 11 (4) ◽  
pp. 195
Author(s):  
Yuanda Patria Tama
Keyword(s):  
Friction Factor ◽  
Traffic Flow ◽  
Public Transportation ◽  
Street Vendor ◽  
Characteristic Factor ◽  
Bus Stop ◽  
Traffic Law ◽  
Road Space ◽  
Side Friction Factor ◽  
Side Friction

The transportation’s problem that common in Indonesia is a limitation of road space and intersection that needed to conduct the traffic flow. An accident and degradation of intersection’s performance, it’s caused by the driver’s attitude which have a less concern to the traffic law. This research attempt to observe the driver violation which influences the characteristic of urban’s intersection to find out the phenomenon of traffic’s signal intersection. The strategy to design the intersection in East Bekasi highway for reducing driver violation by using the side friction factor that consists of extending the radius of junction sleeves, constructing lay bay in bus stop, demolition the street vendor, ojek base and public transportation. Also, the geometric intersection factor consists of installation signs, marka reparation, constructing the pedestrian facility, and specific stopping area for motorcycle, then the traffic’s characteristic factor consists of an intensive supervising by policeman, constructing the priority track to turn left on red and installation signs.

scholarly journals KAJIAN KINERJA PERSIMPANGAN TIDAK BERSINYAL (STUDI KASUS : PERSIMPANGAN TIGA GADUT, JALAN RAYA INDARUNG – BANDAR BUAT, KOTA PADANG)

2019 ◽  
Vol 2 (2) ◽  
Author(s):  
Eko Prayitno ◽  
Veronika Veronika
Keyword(s):  
Traffic Flow ◽  
Environmental Data ◽  
Degree Of Saturation ◽  
Road User ◽  
Total Delay ◽  
The Road ◽  
Traffic Conditions ◽  
Road Capacity ◽  
Side Friction Factor ◽  
Side Friction

The highway is one of the infrastructure for the smooth traffic. One part of the road that are considered necessary to be analyzed and evaluated is an intersection. Three Gadut intersection is non signalized intersection. The traffic flow is quite dense, and lack of discipline of road user factors competing space to pass the crossing, resulting in congestion is very influential on traffic conditions at peak hours in the morning, afternoon and evening. Prior to conducting the survey, the first to do is survey the condition of the intersection that includes geometric characteristics and traffic volume. From the analysis of environmental data, side friction factor to the junction of three Gadut is the criteria being. Rated capacity (C) the smallest is 3706.3 smp/hour, the degree of saturation of 1.1 smp/hour. This value is over the limit permitted values manually indonesian road capacity of 0.8 to 0.9 (1.1> 0.9), it is concluded that the traffic flow is the crossroads of three Gadut saturated traffic flow. The queue probability value between 128.8% - 157.4% with a total delay largest average 11.57 seconds/smp. It is concluded that the chances of a queue at the intersection of three Gadut very large, so it could cause congestion.

Design radius requirements for simple horizontal curves on three-dimensional alignments

2003 ◽  
Vol 30 (6) ◽  
pp. 1022-1033 ◽  
Author(s):  
Said M Easa ◽  
Essam Dabbour
Keyword(s):  
Three Dimensional ◽  
Design Guidelines ◽  
Comfort Level ◽  
Vertical Alignment ◽  
Passenger Cars ◽  
Minimum Radius ◽  
Horizontal Curves ◽  
Design Speed ◽  
Side Friction ◽  
Mathematical Relationships

Current North American design guides have established mathematical relationships to calculate the minimum radius required for horizontal curves as a function of design speed, maximum superelevation, and maximum side friction. For three-dimensional (3-D) alignments, the design guides consider the alignment as two separate horizontal and vertical alignments and consequently ignore the effect of vertical alignment. This paper evaluates the effect of vertical alignment on minimum radius requirements using computer simulation, with a focus on trucks. For 3-D alignments, the results showed that existing design guidelines for minimum radius need to be increased by as much as 20% to achieve the same comfort limit on flat horizontal curves. It is interesting to note that in some cases truck rollover occurred before the side-friction comfort level is reached. This indicates the need for developing a different design control for trucks on 3-D alignments than the comfort criterion used for passenger cars on flat horizontal curves. Based on the simulation results, mathematical models for design radius requirements for passenger cars and trucks were developed.Key words: geometric design, horizontal curve radius, three-dimensional alignments, vehicle stability.

scholarly journals Evaluation of design consistency on horizontal curves for two-lane state roads in terms of vehicle path radius and speed

2016 ◽  
Vol 11 (2) ◽  
pp. 127-135
Author(s):  
Biljana Maljković ◽  
Dražen Cvitanić
Keyword(s):  
Horizontal Curves ◽  
Percentage Difference ◽  
Friction Factors ◽  
The Difference ◽  
Design Speed ◽  
Vehicle Path ◽  
Design Consistency ◽  
Side Friction ◽  
Curve Radius ◽  
The Impact

Experimental investigation was conducted on a 24 km long segment of the two-lane state road to collect the driver behavior data. The research involved 20 drivers driving their own cars equipped with the GPS device. Considering the impact of path radius and speed on the side friction demand, the design consistency on horizontal curves was evaluated by determining the margins of safety. The analysis showed that the vehicle path radii were mainly smaller than curve radius, on average for 12%. Regression analysis indicated that the percentage difference between the curve radius and vehicle path radius is not affected by the speed, speed differential and geometric characteristics of the curve and surrounding elements. Two different margins of safety were analyzed. One is the difference between maximum permissible side friction (based on design speed) and side friction demand, while another is the difference between side friction supply (based on operating speed) and side friction demand. Generally, demands exceeded supply side friction factors on curves with radii smaller than 150 m, whereas “poor” conditions (in terms of Lamm’s consistency levels) were noted for curves under approximately 220 m. Both values are very close to the critical radius below which higher accident rates were observed according to several accident studies. Based on the results of the research, it is proposed to use a 12% smaller curve radius for the evaluation of margin of safety and that curves with radii smaller than 200 m should be avoided on two-lane state roads outside the built-up area.

scholarly journals KELIO TRASOS HORIZONTALIŲJŲ KREIVIŲ ĮTAKA TRANSPORTO SRAUTO GREIČIUI / INFLUENCE OF ROAD ALIGNMENT HORIZONTAL CURVE ON TRANSPORT FLOW OPERATING SPEED

2019 ◽  
Vol 11 (0) ◽  
pp. 1-7
Author(s):  
Mindaugas Šeporaitis ◽  
Viktoras Vorobjovas
Keyword(s):  
Road Network ◽  
Operating Speed ◽  
Horizontal Curve ◽  
The Road ◽  
Horizontal Curves ◽  
Legal Documents ◽  
Transport Flow ◽  
Design Speed ◽  
Side Friction ◽  
Curve Selection

Geometric parameters of road alignment are fundamental elements defining permissible speed and vice versa. Unlike permissible speed, determined operating speed in upgrade projects has a significant impact on the safe movement of transport on the roads. The article reviews the composition of the regional road network in Lithuania, the design speed, the permitted speed, the practical problems of applying the geometry parameters of the road alignment according to the legal documents valid in Lithuania, methods of horizontal curve selection in Lithuania and other countries are analysed in more detail. Comparative initial calculations of horizontal curves were performed using different side friction coefficients. Review summary of analysis conducted and statements are prepared for discussion.

scholarly journals Determination of Applicable Adjacent Horizontal Curve Radii Using Operating Speed

2019 ◽  
Vol 31 (4) ◽  
pp. 443-452
Author(s):  
Dražen Cvitanić ◽  
Biljana Maljković
Keyword(s):  
Dynamic Consistency ◽  
Operating Speed ◽  
Demand Side ◽  
Horizontal Curve ◽  
Driving Dynamic ◽  
The Road ◽  
Design Speed ◽  
Side Friction ◽  
Limiting Values

Design of curves and their adjacent elements presents the greatest safety problem on rural two-lane roads. The use of the existing alignment consistency safety criteria (design, operating speed, and driving dynamic consistency) could have some shortcomings, especially in countries where the project or design speed is in use instead of (higher) operating speed. The consequence is that the designer should use smaller cross fall on curves than needed, while the calculated side friction is lower than in reality. Further, the existing graphs of adjacent curve radii do not take into account that there is a maximum operating speed achieved for a certain radius or long tangent above which it does not increase. This paper presents a methodology for determination of adjacent horizontal curve radii, with and without tangent between, based on the operating speed models which include dependence of operating speeds on tangents and curves on speed of adjacent alignment elements as well as maximum tangent and curve speed. The developed graphs of adjacent radii at the same time include the limiting values of driving dynamic consistency criteria, so the road designer does not need to calculate permissible and demand side friction for every combination of adjacent alignment elements.

Safety Evaluation of Geometric Design Criteria: Horizontal Curve Radius and Side Friction Demand on Rural, Two-Lane Highways

2019 ◽  
Vol 2673 (3) ◽  
pp. 516-525
Author(s):  
Scott Himes ◽  
Richard J. Porter ◽  
Ian Hamilton ◽  
Eric Donnell
Keyword(s):  
Negative Binomial ◽  
Negative Binomial Regression ◽  
Geometric Design ◽  
Design Criteria ◽  
Speed Limit ◽  
Horizontal Curve ◽  
Mass Model ◽  
Design Speed ◽  
Side Friction ◽  
Curve Radius

AASHTO’s A Policy on Geometric Design of Highways and Streets, 6th Edition, provides design criteria for horizontal curve elements based on the point-mass model. The model equates the centripetal force needed to navigate a horizontal curve of a specific radius traveling at the design speed to the combination of superelevation rate and side friction needed to achieve that force. Few researchers have examined the safety impacts of horizontal curve radius, superelevation rate, and design speed through crash-based research. None of the research reviewed included the effects of design speed or superelevation rate in the crash modification factors (CMFs) or functions. This research explored these factors using a negative binomial regression modeling approach based on data collected from the SHRP 2 RID 2.0 for 889 horizontal curves on rural two-lane highways in Indiana and Pennsylvania, which resulted in roadway departure crash modification functions for horizontal curve radius and side friction demand. The crash modification function for side friction demand includes an interactive component of horizontal curve radius and speed and a direct effect of superelevation rate on roadway departure crashes. The results showed that roadway departure crashes are expected to increase for decreasing curve radius, increasing posted speed limit, and decreased superelevation rate. Furthermore, curve-related CMFs were sensitive to the curve radii used in their development. CMFs developed from curves with larger radii tended to result in larger CMFs. Sample applications are provided for computing the effects of changing the horizontal curve radius, posted speed limit, or both on proposed alternatives.

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