New approach to determine number of lanes on freeway upgrades

2008 ◽  
Vol 35 (10) ◽  
pp. 1033-1041 ◽  
Author(s):  
Chen Chen ◽  
Chiu Liu ◽  
Zhongren Wang
Keyword(s):  
Traffic Flow ◽  
Physical Parameters ◽  
Heavy Vehicle ◽  
Physical Factors ◽  
Highway Capacity ◽  
New Approach ◽  
Highway Capacity Manual ◽  
Heavy Trucks ◽  
Road Geometry ◽  
Slow Moving

A slow-moving heavy vehicle can substantially reduce traffic flow because the vehicle acts as a moving bottleneck. In particular, the bottleneck can be initiated on a long uphill freeway section where heavy trucks gain little acceleration and propagate upstream when the percentage of loaded trucks in the traffic is high. This paper finds an interesting relation between the bottlenecks and some physical factors including heavy vehicle characteristics, road geometry, traffic flow theory, and percentage of trucks in traffic. According to this relation, the paper provides two dimensionless physical parameters to characterize the formation and propagation of the queues initiated by loaded trucks on uniform upgrades, respectively. Based on the critical values of these parameters aforementioned, the paper can help transportation engineers to determine that the number of design lanes under the conditions that the growing bottlenecks initiate along upgrade section cannot be resolved by simply using equations and rules suggested in the 2000 edition of the Highway capacity manual.

Speed–Flow–Geometry Relationships and Capacity for Two–Lane Single Carriageway Roads

2014 ◽  
Vol 70 (4) ◽  
Author(s):  
Othman Che Puan ◽  
Nur Syahriza Muhamad Nor ◽  
Zamri Bujang
Keyword(s):  
Simulation Model ◽  
Traffic Flow ◽  
Travel Speed ◽  
The United States ◽  
Highway Capacity ◽  
Microscopic Traffic Simulation ◽  
Highway Capacity Manual ◽  
Speed Flow ◽  
Potential Capacity ◽  
Road Geometry

The current Malaysian practice in road capacity analysis, Malaysian Highway Capacity Manual 2011 (MHCM) is based on a method adopted from the Highway Capacity Manual(HCM) of the United States. All the analysis elements appear to be taken directly from the manual. The rationale for using such a method for Malaysian conditions is not well defined. This paper deliberates the background of the methodology used in the development of speed, flow and geometry relationships and the capacity for single carriageway roads. A microscopic traffic simulation model which is capable of simulating traffic operations on single carriageway roads for a range of road geometry configurations and traffic flow conditions was developed and used to evaluate the potential capacity of a single carriageway road. The results of the analysis indicate that a two-lane single carriageway road is capable of accommodating traffic flow higher than the values derived from the previous HCM. The current version of the HCM also appears to underestimate the vehicles’ travel speed for a range of traffic flows when compared with the results of the simulation model. The MHCM 2011, on the other hand, estimated travel speeds higher than the travels speeds predicted by both the HCM 2010 and simulation model. It shows that there is a different interpretation of LOS F in term of speed between HCM 2010 and MHCM 2011.

Arrival-Based Uniform Delay Model for Oversaturated Signalized Intersections with Poor Progression

2005 ◽  
Vol 1920 (1) ◽  
pp. 86-94
Author(s):  
Rahim F. Benekohal ◽  
Sang-Ock Kim
Keyword(s):  
Signalized Intersections ◽  
Delay Model ◽  
Adjustment Factor ◽  
Highway Capacity ◽  
New Approach ◽  
Highway Capacity Manual ◽  
Traffic Conditions ◽  
Proposed Model ◽  
Uniform Delay ◽  
Control Delays

For oversaturated traffic conditions, the Highway Capacity Manual (HCM) does not apply a progression adjustment factor to the delay model for signalized intersections when there is an initial queue. This causes counterintuitive results in the calculation of delay; for some cases, delay for a nonzero initial queue condition ends up being less than the delay with zero initial queue conditions. Also, for oversaturated traffic conditions, the delay model in the 2000 edition of HCM yields the same uniform delay values for all arrival types when there is an initial queue. This does not seem reasonable because it ignores the effect of platooning on delay. This paper introduces a new approach for computing uniform delay for oversaturated traffic conditions when progression is poor. This approach directly considers the platooning effects in delay and thus eliminates the need to apply a progression adjustment factor. The proposed model is applicable whether there is an initial queue or not. The approach was validated by a comparison of the control delays obtained from a CORSIM simulation to the delays from the proposed model. Validation procedures were conducted on the basis of zero and nonzero initial queue conditions. The proposed approach resulted in more accurate delay values than the HCM model.

Unsignalized Intersection Analysis: Effect of Overlapping Conflicting Traffic Flow on Minor Movement Potential Capacity

1997 ◽  
Vol 1572 (1) ◽  
pp. 86-98
Author(s):  
Christopher J. Fasching
Keyword(s):  
Traffic Flow ◽  
Level Of Service ◽  
Traffic Flows ◽  
Highway Capacity ◽  
Highway Capacity Manual ◽  
Capacity Estimate ◽  
Potential Capacity ◽  
Count Distribution ◽  
Intersection Analysis ◽  
Poisson Count

A particular component of two-way stop unsignalized intersection analyses as presented in the 1994 Highway Capacity Manual (HCM) is described. Specifically, advantages to minor movement capacity are evaluated where traffic flows overlap in multiple lanes. From vehicular arrival data collected by the author, it was determined that the current HCM can significantly underestimate the true potential capacity of minor movements that face multiple lanes of free-flow conflicting traffic. A modification to the HCM procedure is introduced in which an “effective” conflicting flow is calculated on the basis of “blockage” caused by individual lanes of traffic, assuming a Poisson count distribution. In every case examined (24 total), a more accurate potential capacity estimate resulted relative to that determined by the HCM procedure. The modification also resulted in a more accurate level of service in 8 of the 24 cases.

scholarly journals Analisis Kinerja Simpang Tak Bersinyal Jalan A.H. Nasution dan Jalan Cikadut, Kota Bandung. (Hal. 116-123)

2019 ◽  
Vol 5 (2) ◽  
pp. 116
Author(s):  
Muhammad Daryl Marta Pratama ◽  
Elkhasnet Elkhasnet
Keyword(s):  
Traffic Flow ◽  
Initial Conditions ◽  
Degree Of Saturation ◽  
Residential School ◽  
Highway Capacity ◽  
Highway Capacity Manual ◽  
The Road ◽  
Traffic Jams ◽  
Shopping Area ◽  
The City

ABSTRAKPersimpangan merupakan suatu bagian jalan yang menjadi pusat pertemuan dari berbagai pergerakan arus lalu lintas. Pada tipe simpang tak bersinyal, sering dijumpai titik-titik konflik arus lalu lintas yang mengakibatkan kemacetan arus lalu lintas terutama pada saat jam-jam sibuk. Contoh kasus terdapat di Kota Bandung, terjadi pada persimpangan Jalan A.H. Nasution dan Jalan Cikadut. Lokasi ini dipilih karena selain kemacetan yang disebabkan oleh titik-titik konflik arus lalu lintas yang tidak teratur pada saat jam sibuk, di sekitar jalan pada simpang ini juga merupakan kawasan pertokoan, pemukiman, sekolah dan juga terdapat pom bensin. Berdasarkan permasalahan tersebut, dilakukan perhitungan dan analisis data pada kondisi awal simpang, didapat nilai derajat jenuh (DS) sebesar 0,983 untuk pagi hari dan 0,937 untuk sore hari. Karena hasil perhitungan simpang pada kondisi awal tidak memenuhi syarat MKJI 1997, yaitu DS < 0,85, maka perlu dilakukan perhitungan ulang dengan beberapa alternatif agar nilai DS bisa memenuhi.Kata kunci: persimpangan, kemacetan, derajat jenuh, MKJI 1997. ABSTRACTIntersection is a part of the road that becomes the center concourse of various traffic flow movements. In the type of unsignalized intersection, there are often traffic flow conflict points which cause traffic jams, especially during rush hour. Examples of cases are in the City of Bandung, occurred at the intersection of A.H. Nasution Street and Cikadut Street. This location was chosen because in addition to congestion caused by irregular traffic flow conflict points during rush hour, around the road at the intersection this is also a shopping area, residential, school and gas station. Based on these problems, data calculations and analysis are carried out in the initial intersection condition, obtained saturated degree (DS) values of 0,983 in the morning and 0,937 in the afternoon. Because the results of the intersection calculation in the initial conditions did not comply the requirements of the Indonesian Highway Capacity Manual of 1997 (IHCM 1997), that’s DS < 0,85, it is necessary to recalculate with some alternative that value of DS can comply.Keywords: intersection, congestion, degree of saturation, IHCM 1997.

scholarly journals Passenger Car Equivalents on Downgrades of Two-Lane Roads

2020 ◽  
Vol 15 (4) ◽  
pp. 152-173
Author(s):  
Marko Subotić ◽  
Željko Stević ◽  
Edis Softić ◽  
Veljko Radičević
Keyword(s):  
Traffic Flow ◽  
Cross Sections ◽  
Negative Influence ◽  
Flow Conditions ◽  
Highway Capacity ◽  
Passenger Car ◽  
Highway Capacity Manual ◽  
Average Value ◽  
Vehicle Structure ◽  
Passenger Car Equivalent

In this paper, empirical research about Passenger Car Equivalents (PCEs) on the longitudinal downgrade of two-lane roads in Bosnia and Herzegovina has been conducted in order to determine the influence of vehicle structure under free traffic flow conditions. The research has been carried out considering the classes of vehicles at cross-sections on the downgrade of two-lane roads. As a result, the negative influence of vehicle structure under free traffic flow conditions using passenger car equivalents (PCEs) has been determined. The results show that on the downgrade of two-lane roads, the value of passenger car equivalent decreases from the level terrain to the boundary minimum value for the determined downgrade g = −3.00%, after which its value starts to increase slightly. Based on the obtained values, the models calibrated with a second-degree polynomial have been developed to determine the average value of passenger car equivalent as a function of its boundary value. The paper also compares the results obtained by the developed models with the models from the Highway Capacity Manual under free traffic flow conditions. In addition, models for the percentage values of PCE15%, PCE50% and PCE85% have been established.

scholarly journals AFFINITY PROPAGATION CLUSTERING IN DEFINING LEVEL OF SERVICE CRITERIA OF URBAN STREETS

Transport ◽  
2014 ◽  
Vol 29 (4) ◽  
pp. 401-411 ◽  
Author(s):  
Prasanta Kumar Bhuyan ◽  
Smruti Sourava Mohapatra
Keyword(s):  
Traffic Flow ◽  
Heterogeneous Traffic ◽  
Level Of Service ◽  
Highway Capacity ◽  
Highway Capacity Manual ◽  
Urban Streets ◽  
Urban Street ◽  
Indian Context ◽  
Validation Parameters ◽  
Street Segments

Defining Level Of Service (LOS) criteria is very important as this is the first step of LOS analysis but this is not well defined in Indian context. The analysis followed in India is basically adaptation of Highway Capacity Manual (HCM 2000) methodology which is more suitable for developed countries having homogenous traffic pattern. An attempt has been made in this study to define LOS criteria of urban streets for developing countries having heterogeneous traffic flow condition. Defining LOS is basically a classification problem and to solve it Affinity Propagation (AP), a very recently developed cluster algorithm is used. Inventory details and the required speed data are collected from five major street corridors of Greater Mumbai Region in India through the application of Trimble GeoXT Global Positioning System (GPS) receiver. Six validation parameters are used on Free Flow Speed (FFS) data to find the optimal number of clusters, which is required for the classification of street segments into number of classes. After that speed data collected during both peak and off-peak hours are averaged over street segments and clustered into six groups to get the speed ranges of different LOS categories. Using validation parameters, considering the physical and surrounding environmental characteristics it is found that street segments can be classified into four classes in Indian context as mentioned in Highway Capacity Manual 2000. However, the FFS range for urban street class IV (urban design category) is significantly lower because of varying road geometric characteristics. The speed ranges of LOS categories under urban street classes are proportionately lower to that values mentioned in HCM 2000 because of highly heterogeneous traffic flow on urban Indian roads. The travel speed data collection procedure using GPS is simple and accurate. In addition, AP clustering is highly efficient in terms of time saving and provides a very accurate solution to classification problems. Hence, both GPS and AP techniques can be applied in other countries to define the speed ranges of LOS categories considering the local conditions.

scholarly journals CALIBRATING THE PASSENGER CAR EQUIVALENT ON ITALIAN TWO LINE HIGHWAYS: A CASE STUDY

Transport ◽  
2013 ◽  
Vol 29 (4) ◽  
pp. 449-456 ◽  
Author(s):  
Mario De Luca ◽  
Gianluca Dell’Acqua
Keyword(s):  
Traffic Flow ◽  
Local Level ◽  
Highway Capacity ◽  
Passenger Car ◽  
Highway Capacity Manual ◽  
Passenger Car Equivalent ◽  
Basic Parameters ◽  
The Difference ◽  
Qualitative Measure ◽  
The U.S

The Level Of Service (LOS) of a road infrastructure, a concept introduced for the first time in the Highway Capacity Manual (second edition), is defined as the ‘qualitative measure of traffic conditions and their perception by users’. The Highway Capacity Manual, developed in the U.S., is still the most highly internationally credited reference text in the study of vehicular traffic. The method proposed by the Highway Capacity Manual is based mainly on studies and research compiled in the U.S., so in order to apply this method to other realities (e.g. Italy), research needs to be carried out at a local level. In this study, a series of studies were carried out to verify the transferability of these procedures to two roads classified as ‘two-lane highways’. Two fixed RTMS (Remote Traffic Microwave Sensor) were used to record traffic data for two sections located at 3100 km on the SP30 and at 8900 km on the SP175 from 1 January to 31 December 2010. From the data, it was possible to determine not only the relationships between the basic parameters of the traffic flow, but also the (Passenger Car Equivalent) (PCE) values. The results showed that the PCEs analyzed vary significantly with vehicular flow, while they are scarcely affected by changes in speed. In particular, with respect to the vehicular flow, although they have the same range recorded in the Highway Capacity Manual (2010) (between 1 and 2), they tend to be higher than those given in the manual, and the difference tends to diminish beyond a flow rate of 400÷450 pcphpl; the PCE coefficients also tend towards 1 (i.e., the condition where a heavy vehicle is comparable to a car) with range values approaching 1000 pcphpl. In addition, for these values, the traffic-flow diagrams obtained, showed speeds (defined as the critical speed) close to 50÷55 km/h (with the exception of the study conducted on the SP175 in direction d2, which is considerably higher).

scholarly journals Traffic management of Udayana University Sudirman campus intersection using Vissim software

2019 ◽  
Vol 276 ◽  
pp. 03006
Author(s):  
Putu Alit Suthanaya ◽  
Ngurah Upadiana
Keyword(s):  
Traffic Flow ◽  
Traffic Congestion ◽  
Traffic Management ◽  
Signal Timing ◽  
Data Traffic ◽  
University Campus ◽  
Highway Capacity ◽  
Highway Capacity Manual ◽  
Traffic Flow Management ◽  
The City

The city of Denpasar is the capital of Bali Province, as well as the centre of various activities including government offices, hospitals, schools/ universities, trade and services, as well as tourism. Traffic congestion in the city of Denpasar is increasing from year to year, especially at the point of the intersection node, such as at the signalised intersection of Udayana University Sudirman Campus. The high trip attraction to Udayana University Campus has exacerbated the congestion of the intersection. The purpose of this study was to examine an alternative to managing the traffic flow using the Vissim software. The required data included the intersection geometric data, traffic volume and signal timing. The calculation of the intersection’s performance was conducted based on the Indonesian Highway Capacity Manual (IHCM). The simulation of the traffic flow management was conducted with the help of the Vissim software. The results of the performance analysis of the intersection conduced using Vissim Software indicated that the application of Vissim software was valid. The traffic management proposed has reduced both queue length and delay time.

scholarly journals On-Street Parking and Traffic Flow Performance at Kapasan Shopping Area Surabaya

2020 ◽  
Vol 3 (1) ◽  
pp. 9
Author(s):  
Amrita Winaya
Keyword(s):  
Traffic Flow ◽  
Traffic Congestion ◽  
Level Of Service ◽  
Highway Capacity ◽  
Demand And Supply ◽  
Highway Capacity Manual ◽  
The Road ◽  
Shopping Area ◽  
Trading Activities ◽  
On The Road

Traffic congestion is a problem that is often faced by Indonesian big cities. It is related to land use in an area that causes on-street parking. The main cause is the imbalance between demand and supply, namely the need for parking during rush hour exceeds the capacity of existing parking. Another consequence is the increasing of side barriers resulting in the delays on certain roads. Shopping area in Jl.Kapasan, Surabaya is one of the densely areas attracted most people of Surabaya to conduct trading activities and shopping for daily needs. The denstiy of this region will affect the performance of traffic flow and causing delays.The study aims to identify on-street parking in Jl.Kapasan shopping area, consequences arising from parking on the road, and determine the level of service or performance of roads around this shopping area. The analytical methods used are derived from Indonesian Highway Capacity Manual 1997. Based on calculation and analysis, the capacity of Jl.Kapasan without parking on the road was 1468 pcu/hour and with on-street parking was only 1276 pcu/hour.

scholarly journals COMPARATIVE ANALYSIS OF METHODS FOR DETERMINATION OF SUPPLY FLOWS

2021 ◽  
pp. 64-78
Author(s):  
Nataliia Semchenko ◽  
Olha Kholodova ◽  
Maryna Buhaiova
Keyword(s):  
Comparative Analysis ◽  
Traffic Flow ◽  
Analytical Calculation ◽  
Signalized Intersections ◽  
Highway Capacity ◽  
Highway Capacity Manual ◽  
Flow Parameters ◽  
Definition Of ◽  
Saturation Flow

Problem. The capacity of signalized intersections is determined using the concept of "saturation flow". It is the main characteristic in the process of their analysis, design and calculation. The work is devoted to solving the scientific-applied problem of increasing the efficiency of the signalized intersection at one level by choosing a rational method of determining saturation flows for these characteristics of traffic flows, geometric parameters of the intersection and infrastructure in its area. The subject of the study is the influence of the main characteristics of the traffic flow, parameters and infrastructure of the intersection on the saturation flow value. Goal. The aim of the work is the analysis of the influence of the main characteristics of the traffic flow, parameters and infrastructure of the intersection on the saturation flow value. Methodology. The calculation of the control regime at the intersection is based on determining the relation between the traffic intensity of vehicles at the intersection and the saturation flow value, which changes under the influence of a number of factors. Analytical calculation of the saturation flow value is based on using of correction factors that take into account the influence of these factors. Results. The methods of determination of saturation flows are analyzed out in the work; performed a comparative analysis of the definition of ideal saturation flows by different methods; a comparative analysis of the determination of the saturation flow correction coefficients for the parameters that have an effect on it were performed; the estimation of discrepancy at calculations of coefficients of correction of saturation flows by various methods is done; the list of coefficients which need to be considered at definition of their influence on a saturation flow is refined. Originality. In oppose to classical and other approaches to determining the saturation flow, the method recommended by the American "Highway Capacity Manual" takes into account more parameters of influence. It is proposed to use this method for the saturation flow calculation, but with an updated list of coefficients that must be taken into account in the calculations. Practical value. The results of the work can be used in the practice of improving the efficiency of signalized intersections in sections of the urban road network, as well as in further research on this topic.

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