Consistency of Interchange Outer Connection Ramps

2020 ◽  
Author(s):  
H.R. Al-Masaeid ◽  
Tareq M. Magsi ◽  
Hatem H. Almasaeid
Keyword(s):  
Traffic Accidents ◽  
Deflection Angle ◽  
Flow Speed ◽  
Traffic Volume ◽  
Free Flow ◽  
Operating Speed ◽  
Speed Reduction ◽  
Free Flow Speed ◽  
Traffic Volumes ◽  
Geometric Variables

Interchange ramps need a proper and consistent geometric design to avoid possible traffic accidents. The objective of this study is to develop guidelines for consistent design of outer connection ramps. As such, 47 ramps were selected from18 different interchanges in Jordan. Free-flow speed measurements, for different vehicle classes, were taken along ramps and at predefined points. Also, traffic accidents, geometric variables, and traffic volumes were obtained. For circular ramps, the analysis indicated that the operating speed reduction is strongly affected by radius and deflection angle of the curve. The radius of the first curve had the greatest impact on speed reduction on curve-straight-curve ramps. For reverse-curve ramps, the ratio of the radii should be 6:4:9 to achieve a good consistent design for cars, provided that the radius of the first curve exceeds 110 m. Further analysis indicated that speed reduction, geometric variables, and traffic volume are influenced the accident occurrences.

Application of Moving Car Observer Method for Measuring Free Flow Speed on Two-lane Highways

2014 ◽  
Vol 69 (6) ◽  
Author(s):  
Othman Che Puan ◽  
Muttaka Na’iya Ibrahim ◽  
Usman Tasiu Abdurrahman
Keyword(s):  
Field Measurement ◽  
Flow Speed ◽  
Operating Conditions ◽  
Free Flow ◽  
Geometric Features ◽  
Highway Capacity ◽  
Highway Capacity Manual ◽  
Free Flow Speed ◽  
The Subject ◽  
Low Traffic

There exists a need to evaluate the performance indicator that reflects the current level of service (LOS) of the subject facility to justify any decision making on expenditures to be made for improving the performance level of a road facility. Free-flow speed (FFS) is one of the key parameters associated with LOS assessment for two-lane highways. Application of a more realistic approach for assessing road’s performance indicators would result in better estimates which could in turn suggest the most appropriate decision to be made (for situations where upgrading is needed); especially, in terms of finance, materials and human resources. FFS is the driver’s desired speed at low traffic volume condition and in the absence of traffic control devices. Its estimation is significant in the analysis of two-lane highways through which average travel speed (ATS); an LOS indicator for the subject road class is determined. The Highway Capacity Manual (HCM) 2010 offers an indirect method for field estimation of FSS based on the highway operating conditions in terms of base-free-flow-speed (BFFS). It is however, recommended by the same manual that direct field FSS measurement approach is most preferred. The Malaysian Highway Capacity Manual (MHCM) established a model for estimating FFS based on BFFS, the geometric features of the highway and proportion of motorcycles in the traffic stream. Estimating FFS based on BFFS is regarded as an indirect approach which is only resorted to, if direct field measurement proved difficult or not feasible. This paper presents the application of moving car observer (MCO) method for direct field measurement of FFS. Data for the study were collected on six segments of two-lane highways with varying geometric features. FFS estimates from MCO method were compared with those based on MHCM model. Findings from the study revealed that FFS values from MCO method seem to be consistently lower than those based on MHCM model. To ascertain the extent of the difference between the FFS values from the two approaches, student t-statistics was used. The t-statistics revealed a P–value of less than 0.05 (P < 0.05) which implies that there is a statistically significant difference between the two sets of data. Since MCO method was conducted under low traffic flow (most desired condition for field observation), it can be suggested that MCO estimates of FFS represent the actual scenario. A relationship was therefore developed between the estimates from the two methods. Thus, if the MHCM model is to be applied, the measured value needs to be adjusted based on the relationship developed between the two approaches.

scholarly journals An Efficient Scheduling of Flyover at Grade Intersection under Mixed Traffic Environment

2021 ◽  
Vol 9 (VI) ◽  
pp. 824-833
Author(s):  
Shradha S. Zanjad
Keyword(s):  
Queue Length ◽  
Fixed Time ◽  
Flow Speed ◽  
Free Flow ◽  
Mixed Traffic ◽  
Time Control ◽  
Traffic Environment ◽  
Free Flow Speed ◽  
Big Cities

A flyover is a bridge constructed along an intersecting highway over an at-grade intersection. It allows two –direction traffic to flow at free flow speed on the bridge. The flyover is one of the methods for solving traffic problems at at-grade junctions on highways including capacity, congestion, long delay and queue length. Traffic signalization at the upgraded intersection often uses the same fixed time control plans, even after the installation of a flyover over the intersection. Most of the flyovers in India are constructed at the junctions on highway bypasses of big cities. The present work deals with a efficient scheduling of flyover at the grade intersection under the mixed traffic environment. From the results and the modeling carried out in the “SIDRA Intersection” software different points are observed. The present work consists of the Proposed Intersection at Rajkamal Square, Amravati.

scholarly journals ANALISIS KAPASITAS DAN KINERJA LALU LINTAS PADA RUAS JALAN JENDERAL SUDIRMAN JAKARTA

2021 ◽  
Vol 4 (1) ◽  
pp. 95
Author(s):  
Sarah Haryati ◽  
Najid Najid
Keyword(s):  
Flow Speed ◽  
Traffic Volume ◽  
Capital City ◽  
Free Flow ◽  
Degree Of Saturation ◽  
Level Of Service ◽  
Traffic Jam ◽  
Traffic Capacity ◽  
Traffic Behavior

Jakarta as the capital city of Indonesia is the center of economy, culture, and politics. Jenderal Sudirman street always crowded with passing vehicles, traffic snarls up everyday. The causes of these traffic jam is an increase the number of vehicles and cause a change in traffic behavior. Theoretically there is a fudamental relationship between flow, speed, & density, so the purpose of these research are to analyze and evaluate performance of traffic capacity in various conditions based on Manual Kapasitas Jalan Indonesia 1997 and Greenshields model. Conclusion of the analysis are, after compared with traffic volume, capacity and speed based on MKJI are 3.127,6 pcu/hour and 55,7 km/hour, but the capacity of the model are selected because it’s largest, for sudirman – thamrin it’s 8.272,5 pcu/hour, and for thamrin – sudirman it’s 8.067,9 pcu/hour, While the calculation of free flow for sudirman – thamrin it’s 41.2 km/hour the lowest occurs in  evening, and for thamrin – sudirman it’s 43,9 km/hour the lowest occurs in  afternoon. The largest capacity it’s used for the next analysis, the next analysis are calculating degree of saturation and level of service, the result  shows that the roads are at C and D.ABSTRAKJakarta ibu kota negara Indonesia merupakan pusat ekonomi, budaya, dan politik. Sebuah jalan di Jakarta yaitu Jenderal Sudirman selalu dipadati kendaraan. Lalu lintas di Jalan Jenderal Sudirman setiap hari mengalami kemacetan penyebabnya adalah peningkatan jumlah kendaraan di dalam kota dan menyebabkan perubahan perilaku lalu lintas, secara teoritis terdapat hubungan yang mendasar antara arus, kecepatan, dan kepadatan. Tujuan penelitian ini adalah untuk menganalisis, mengevaluasi kinerja dan kapasitas lalu lintas di berbagai macam kondisi, tentu berdasarkan pedoman Manual Kapasitas Jalan Indonesia dan kapasitas model Greenshields. Dari hasil analisis hasil perhitungan kapasitas dan kecepatan arus bebas berdasarkan MKJI sebesar 3.127,6 smp/jam dan 55,7 km/jam setelah dibandingkan dengan volume lalu lintas dipilih kapasitas model yang terbesar yaitu sebesar 8.272,5 smp/jam pada sudirman - thamrin & 8.067,9 smp/jam pada thamrin - sudirman, dan hasil perhitungan kecepatan arus bebas terendah sebesar 41,2 km/jam di sore hari untuk sudirman - thamrin, sebaliknya thamrin - sudirman terendah sebesar 43,9 km/jam di siang hari. Gunakan kapasitas yang terpilih tersebut untuk analisis berikutnya yaitu perhitungan ratio perbandingan arus dan kapasitas (DS) dan tingkat pelayanan yan berada pada tingkat pelayanan huruf C dan D di kedua arahnya.

scholarly journals The Effect of Congestion Pricing Scheme on the Generalized Cost and Speed of a Motorcycle

2016 ◽  
Vol 15 (1) ◽  
pp. 95-106
Author(s):  
Gito SUGIYANTO
Keyword(s):  
Traffic Congestion ◽  
Demand Management ◽  
Congestion Pricing ◽  
Flow Speed ◽  
Free Flow ◽  
Vehicle Speed ◽  
Traffic Jams ◽  
Pricing Scheme ◽  
Free Flow Speed ◽  
Generalized Cost

Traffic congestion is one of the significant transport problems in many cities in developing countries. Increased economic growth and motorization have created more traffic congestion. The application of transportation demand management like congestion pricing can reduce congestion, pollution and increase road safety. The aim of this research is to estimate the congestion pricing of motorcycles and the effect of a congestion pricing scheme on the generalized cost and speed of a motorcycle. The amount of congestion pricing is the difference between actual generalized cost in traffic jams and in free-flow speed conditions. The analysis approach using 3 components of generalized costs of motorcycle: vehicle operating, travel time and externality cost (pollution cost). The approach to analyze the pollution cost is marginal-health cost and fuel consumption in traffic jams and free-flow speed conditions. The value of time based on Gross Regional Domestic Product per capita in Yogyakarta City in October 2012. The simulation to estimate the effect of congestion pricing using Equilibre Multimodal, Multimodal Equilibrium-2 (EMME-2) software. The results of this study show that while the free-flow speed of a motorcycle to the city of Yogyakarta is 42.42 km/h, with corresponding generalized cost of IDR1098 per trip, the actual speed in traffic jams is 10.77 km/h producing a generalized cost of IDR2767 per trip, giving a congestion pricing for a motorcycle of IDR1669 per trip. Based on the simulation by using EMME-2, the effect of congestion pricing will increase on vehicle speed by 0.72 to 8.11 %. The highest increase of vehicle speed occurred in Malioboro Street at 2.26 km/h, while the largest decrease occurred in Mayor Suryotomo Street at north-south direction at 1.07 km/h. Another effect of this application for motorcycles users will decrease the generalized cost by 1.09 to 6.63 %.

scholarly journals Modelling Free Flow Speed on Two-Lane Rural Highways in Bosnia and Herzegovina

2014 ◽  
Vol 26 (2) ◽  
pp. 121-127 ◽  
Author(s):  
Ivan Lovrić ◽  
Dražen Cvitanić ◽  
Deana Breški
Keyword(s):  
Field Survey ◽  
Evaluation Model ◽  
Practical Method ◽  
Flow Speed ◽  
Free Flow ◽  
Rural Highways ◽  
Speed Flow ◽  
Free Flow Speed ◽  
Flow Diagrams ◽  
Analysis Models

Free flow speed is used as a parameter in transportation planning and capacity analysis models, as well as speed-flow diagrams. Many of these models suggest estimating free flow speed according to measurements from similar highways, which is not a practical method for use in B&H. This paper first discusses problems with using these methodologies in conditions prevailing in B&H and then presents a free flow speed evaluation model developed from a comprehensive field survey conducted on nine homogeneous sections of state and regional roads.

scholarly journals Freeway Free Flow Speed: a Case Study in Italy

2012 ◽  
Vol 54 ◽  
pp. 628-636 ◽  
Author(s):  
Mario De Luca ◽  
Renato Lamberti ◽  
Gianluca Dell’Acqua
Keyword(s):  
Flow Speed ◽  
Free Flow ◽  
Free Flow Speed

Impact of Rainfall Condition on Traffic Flow and Speed: A Case Study in Johor and Terengganu

2014 ◽  
Vol 70 (4) ◽  
Author(s):  
Nordiana Mashros ◽  
Johnnie Ben- Edigbe ◽  
Sitti Asmah Hassan ◽  
Norhidayah Abdul Hassan ◽  
Nor Zurairahetty Mohd Yunus
Keyword(s):  
Traffic Flow ◽  
Monsoon Season ◽  
Flow Speed ◽  
Free Flow ◽  
Road User ◽  
Traffic Data ◽  
Average Volume ◽  
Rainfall Condition ◽  
Free Flow Speed ◽  
The Impact

This paper explores the impact of various rainfall conditions on traffic flow and speed at selected location in Terengganu and Johor using data collected on two-lane highway. The study aims to quantify the effect of rainfall on average volume, capacity, mean speed, free-flow speed and speed at capacity. This study is important to come out with recommendation for managing traffic under rainfall condition. Traffic data were generated using automatic traffic counters for about three months during the monsoon season. Rainfall data were obtained from nearest surface rain gauge station. Detailed vehicular information logged by the counters were retrieved and processed into dry and various rainfall conditions. Only daylight traffic data have been used in this paper. The effect of rain on traffic flow and speed for each condition were then analysed separately and compared. The results indicated that average volumes shows no pronounce effect under rainfall condition compared to those under dry condition. Other parameters, however, show a decrease under rainfall condition. Capacity dropped by 2-32%, mean speed, free-flow speed and speed at capacity reduced by 3-14%, 1-14% and 3-17%, respectively. The paper recommends that findings from the study can be incorporated with variable message sign, local radio and television, and variable speed limit sign which should help traffic management to provide safer and more proactive driving experiences to the road user. The paper concluded that rainfall irrespective of their intensities have impact on traffic flow and speed except average volume.

scholarly journals Relationship Between Traffic Volume and Accident Frequency at Intersections

2020 ◽  
Vol 17 (4) ◽  
pp. 1393
Author(s):  
Angus Eugene Retallack ◽  
Bertram Ostendorf
Keyword(s):  
Traffic Accidents ◽  
Negative Binomial ◽  
Motor Vehicle ◽  
Traffic Volume ◽  
Accident Risk ◽  
Vehicle Accidents ◽  
Accident Frequency ◽  
Traffic Volumes ◽  
Congestion Index ◽  
Binomial Models

Driven by the high social costs and emotional trauma that result from traffic accidents around the world, research into understanding the factors that influence accident occurrence is critical. There is a lack of consensus about how the management of congestion may affect traffic accidents. This paper aims to improve our understanding of this relationship by analysing accidents at 120 intersections in Adelaide, Australia. Data comprised of 1629 motor vehicle accidents with traffic volumes from a dataset of more than five million hourly measurements. The effect of rainfall was also examined. Results showed an approximately linear relationship between traffic volume and accident frequency at lower traffic volumes. In the highest traffic volumes, poisson and negative binomial models showed a significant quadratic explanatory term as accident frequency increases at a higher rate. This implies that focusing management efforts on avoiding these conditions would be most effective in reducing accident frequency. The relative risk of rainfall on accident frequency decreases with increasing congestion index. Accident risk is five times greater during rain at low congestion levels, successively decreasing to no elevated risk at the highest congestion level. No significant effect of congestion index on accident severity was detected.

scholarly journals The Development and Assessment of Free-Flow Speed Models under Heterogeneous Traffic in Facilitating Sustainable Inter Urban Multilane Highways

2020 ◽  
Vol 12 (8) ◽  
pp. 3445
Author(s):  
Lee Vien Leong ◽  
Tuti Azmalia Azai ◽  
Wins Cott Goh ◽  
Mohammed Bally Mahdi
Keyword(s):  
Field Measurements ◽  
Flow Speed ◽  
Heterogeneous Traffic ◽  
Free Flow ◽  
Suitable Model ◽  
Traffic Conditions ◽  
Sustainable Environment ◽  
Road Users ◽  
Free Flow Speed ◽  
Road Characteristics

The desired speed that drivers can drive without being obstructed or influenced by other road users is characterized as free-flow speed. However, free-flow speed can be influenced by other factors such as the characteristics of the vehicle, driver, road conditions, weather, and speed limits. Due to the country’s heterogeneous traffic conditions, this study aims to develop and assess free-flow speed models based on different vehicle classes and road characteristics in Malaysia. Data were sampled at 16 sites of multilane highways in Malaysia. Analyses of free-flow speed were conducted based on individual and grouped vehicle classes. Subsequently, multiple regression analyses were conducted based on these grouped vehicle classes to develop free-flow speed models. The findings show that the model with the grouping of all vehicles, which includes heavy vehicles and motorcycles, is the most suitable model as it yields the best results based on the performance indicators. The development of a free-flow speed model based on local traffic conditions, which can accurately estimate free-flow speed without having to conduct field measurements, is essential for saving time and costs in data collection. The findings from this study will contribute to improving the design of multilane highways and, ultimately, ensuring the sustainable environment of road networks.

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