Freeway Planning Methodology

2003 ◽  
Vol 1852 (1) ◽  
pp. 63-68
Author(s):  
Elena Shenk Prassas ◽  
Douglas McLeod ◽  
Gina Bonyani
Keyword(s):  
Rural Areas ◽  
Travel Speed ◽  
Average Density ◽  
Highway Capacity ◽  
Highway Capacity Manual ◽  
Annual Average Daily Traffic ◽  
Engineering Level ◽  
Florida Department ◽  
Planning Methodology ◽  
Parameter Values

A major new chapter of the Highway Capacity Manual (HCM) 2000 is on freeway facilities. It is a detailed operational methodology that combines analyses of basic freeway segments, weaving areas, off-ramp areas, and on-ramp areas. However, the new chapter does not contain guidance or examples for planning or preliminary engineering applications. To meet its numerous needs, Florida Department of Transportation engineers wanted to develop a freeway facility application that extends the HCM for generalized planning and preliminary engineering purposes but is not inconsistent with HCM 2000. Such a methodology was developed, documented, made into an executable software program called FREEPLAN, and is now being implemented throughout the state. The methodology is firmly based on HCM detailed analysis procedures but has assumptions and defaults that allow planners and engineers to use it effectively. At a generalized planning level, the basic construct was to provide tables of design volumes, v, and annual average daily traffic that could be achieved for various levels of service and freeway configurations for the default parameter values. At a preliminary engineering level, specific freeway facility inputs are used to determine v/c ratio, average travel speed, average density, and level-of-service grades. The initial results of applying the Florida freeway planning methodology to actual Florida data were outstanding in both urbanized and rural areas.

Uncertainty in Operational Analysis of Two-Lane Highways

2002 ◽  
Vol 1802 (1) ◽  
pp. 105-114 ◽  
Author(s):  
R. Tapio Luttinen
Keyword(s):  
Input Data ◽  
Travel Speed ◽  
Level Of Service ◽  
Model Parameters ◽  
Highway Capacity ◽  
Highway Capacity Manual ◽  
Operational Analysis ◽  
Percent Time ◽  
Different Types ◽  
Percent Time Spent Following

The Highway Capacity Manual (HCM) 2000 provides methods to estimate performance measures and the level of service for different types of traffic facilities. Because neither the input data nor the model parameters are totally accurate, there is an element of uncertainty in the results. An analytical method was used to estimate the uncertainty in the service measures of two-lane highways. The input data and the model parameters were considered as random variables. The propagation of error through the arithmetic operations in the HCM 2000 methodology was estimated. Finally, the uncertainty in the average travel speed and percent time spent following was analyzed, and four approaches were considered to deal with uncertainty in the level of service.

scholarly journals Travel Time Estimation on Urban Street Segment

2018 ◽  
Vol 30 (1) ◽  
pp. 115-120 ◽  
Author(s):  
Jelena Kajalić ◽  
Nikola Čelar ◽  
Stamenka Stanković
Keyword(s):  
Travel Time ◽  
Time Estimation ◽  
Travel Speed ◽  
Degree Of Saturation ◽  
Level Of Service ◽  
Travel Time Estimation ◽  
Highway Capacity ◽  
Local Conditions ◽  
Highway Capacity Manual ◽  
Urban Streets

Level of service (LOS) is used as the main indicator of transport quality on urban roads and it is estimated based on the travel speed. The main objective of this study is to determine which of the existing models for travel speed calculation is most suitable for local conditions. The study uses actual data gathered in travel time survey on urban streets, recorded by applying second by second GPS data. The survey is limited to traffic flow in saturated conditions. The RMSE method (Root Mean Square Error) is used for research results comparison with relevant models: Akcelik, HCM (Highway Capacity Manual), Singapore model and modified BPR (the Bureau of Public Roads) function (Dowling - Skabardonis). The lowest deviation in local conditions for urban streets with standardized intersection distance (400-500 m) is demonstrated by Akcelik model. However, for streets with lower signal density (<1 signal/km) the correlation between speed and degree of saturation is best presented by HCM and Singapore model. According to test results, Akcelik model was adopted for travel speed estimation which can be the basis for determining the level of service in urban streets with standardized intersection distance and coordinated signal timing under local conditions.

scholarly journals Self-Organizing Tree Algorithm (SOTA) Clustering for Defining Level of Service (LOS) Criteria of Urban Streets

2018 ◽  
Vol 47 (4) ◽  
pp. 309-317
Author(s):  
Amit Kumar Das ◽  
Prasanta Kumar Bhuyan
Keyword(s):  
Travel Speed ◽  
Flow Speed ◽  
Free Flow ◽  
Level Of Service ◽  
Highway Capacity ◽  
Tree Algorithm ◽  
Highway Capacity Manual ◽  
Urban Streets ◽  
Flow Speeds ◽  
Self Organizing

This study is intended to define the Free Flow Speed (FFS) ranges of urban street classes and speed ranges of Level of Service (LOS) categories. In order to accomplish the study FFS data and average travel speed data were collected on five urban road corridors in the city of Mumbai, India. Mid-sized vehicle (car) mounted with Global Positioning System (GPS) device was used for the collection of large number of speed data. Self-Organizing Tree Algorithm (SOTA) clustering method and five cluster validation measures were used to classify the urban streets and LOS categories. The above study divulges that the speed ranges for different LOS categories are lower than that suggested by Highway Capacity Manual (HCM) 2000. Also it has been observed that average travel speed of LOS categories expressed in percentage of free flow speeds closely resembles the percentages mentioned in HCM 2010.

scholarly journals Traffic Operations on Rural Two-Lane Highways: A Review on Performance Measures and Indicators

2018 ◽  
Vol 2672 (15) ◽  
pp. 66-74 ◽  
Author(s):  
Ahmed Al-Kaisy ◽  
Amirhossein Jafari ◽  
Scott Washburn ◽  
Tapio Lutinnen ◽  
Richard Dowling
Keyword(s):  
United States ◽  
Performance Measures ◽  
Rural Areas ◽  
Subjective Assessment ◽  
The United States ◽  
Highway Capacity ◽  
Highway Capacity Manual ◽  
Improvement Programs ◽  
Performance Determinants ◽  
Highway Facilities

Two- lane highways constitute a large proportion of the highway system in the United States, particularly in rural areas. Performance evaluation on those highways is the basis for planning, upgrade, and improvement programs. Such evaluations are conducted using performance measures that should ideally be correlated to performance determinants on those highways. Unlike other highway facilities, two-lane highway performance is notably affected by the platooning phenomenon, which is believed to be a function of traffic level and passing opportunities. Over the last couple of decades, several studies have addressed performance measures on two-lane highways, and are mainly driven by the reported limitations of the current measures used by the Highway Capacity Manual (HCM). This review aims to summarize the performance measures that have been published in the literature or used in practice both in the United States and abroad. The review starts with an historical overview of the HCM performance measures since its inception in 1950. It then discusses the most important criteria for measures to be more effective in describing performance, before presenting the review results for measures that have been proposed in literature or reported as being used in practice. Finally, a subjective assessment of all performance measures against the set of criteria outlined in the article is presented. The review presented in this paper provides information that is valuable for practitioners and researchers in understating the alternative measures for assessing performance on two-lane highways, and the limitations and merits associated with those measures.

scholarly journals ESTIMACIÓN DEL NIVEL DE SERVICIO DE UN CARRIL LENTO

2016 ◽  
Author(s):  
Víctor Gabriel Valencia Alaix ◽  
Alfredo García García
Keyword(s):  
Travel Speed ◽  
Highway Safety ◽  
Design Model ◽  
Highway Capacity ◽  
Highway Capacity Manual ◽  
Percent Time ◽  
Safety Design ◽  
Percent Time Spent Following

La operación vehicular en una carretera convencional depende de la atención adecuada de los adelantamientos de los vehículos lentos por parte de los más rápidos; una alternativa es mediante la provisión de carriles auxiliares a lo largo de la vía antes de pasar a una carretera multicarril.El objetivo es calibrar el modelo de simulación TWOPAS y aplicarlo en una carretera convencional española para estimar y comparar el nivel de servicio estimado en ella y en un carril lento con el resultado del procedimiento del Highway Capacity Manual - HCM.Se observó la operación vehicular en una carretera convencional de España mediante el registro a través de cámaras de control dispuestas a lo largo de la carretera, y en el carril lento, de manera que sirvió para calibrar el modelo de microsimulación TWOPAS considerando parámetros operacionales del parque automotor y aplicándolo para estimar el nivel de servicio.Se aplicó el procedimiento del HCM para estimar el nivel de servicio en segmentos de carretera con carril lento para comparar sus resultados con los obtenidos en la simulación.El modelo de simulación usado fue el TWOPAS, inserto en el Traffic Analisys Module (TAM) del Interactive Highway Safety Design Model (IHSDM), cuyos resultados en términos de Percent Time Spent Following (PTSF), Average Travel Speed (ATS) y otros permite la evaluación operacional.Los resultados y conclusiones permiten valorar la utilidad del modelo, la correspondencia de la realidad operacional en carretera y la norma española y la conveniencia operacional del carril lento estudiado.DOI: http://dx.doi.org/10.4995/CIT2016.2016.4220

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.

Analyzing Arterial Streets in Near-Capacity or Overflow Conditions

2000 ◽  
Vol 1710 (1) ◽  
pp. 231-238
Author(s):  
Andrzej P. Tarko
Keyword(s):  
Current Method ◽  
Travel Speed ◽  
Improved Method ◽  
Adjustment Factor ◽  
Highway Capacity ◽  
Highway Capacity Manual ◽  
Arterial Streets ◽  
Traffic Volumes ◽  
Negative Effect ◽  
Urban Arterial

Filtering and metering of traffic at highway bottlenecks influence delay and travel speeds along congested arterial streets. The current Highway Capacity Manual (HCM) method of analyzing urban arterial streets uses the filtering and metering adjustment factor I but does not give recommendations on how to adjust traffic volumes. An improved method of analyzing signalized arterial streets affected by bottlenecks is proposed. A set of equations has been derived to calculate the coefficient I and to adjust the traffic volumes. Conditions in which measured or predicted volumes should be adjusted and conditions in which they do not have to be adjusted are specified. The proposed method incorporates the effect of turning volumes, a feature not present in the current HCM method. A sensitivity analysis of travel speeds along an example signalized arterial street illustrates the filtering and metering effects and compares the results produced by the existing and proposed methods. The differences in the results are considerable. In addition, the significant effect of turning volumes has been confirmed. The proposed method tends to produce travel speeds higher than the values obtained with the current method, which concurs with comments from the users of the HCM that the current method underestimates travel speeds. The filtering equation has been derived with the assumptions of fixed capacity and no vehicle dispersion. Under the conditions violating these assumptions, the filtering equation may underestimate I. Further, the proposed method does not incorporate the effect of long queues blocking upstream lane groups. The negative effect on travel speed estimates along the entire arterial should be limited or negligible.

Queue Analysis at Work Zones from Field-Collected Data

2021 ◽  
pp. 036119812110252
Author(s):  
Julius Codjoe ◽  
Raju Thapa ◽  
Elisabeta Mitran
Keyword(s):  
Flow Rate ◽  
Discharge Rate ◽  
Time Of Day ◽  
Work Zone ◽  
Speed Ratio ◽  
Work Zones ◽  
Highway Capacity ◽  
Local Data ◽  
Highway Capacity Manual ◽  
Annual Average Daily Traffic

Estimation of the capacity of work zones is vital to manage the possibility of traffic flows exceeding capacity and resulting in unbearable queues during work zone lane closures. A plethora of research papers have studied several ways to estimate work zone capacity, with the Highway Capacity Manual (HCM) having its own methodology to estimate capacity based on various site characteristics. However, HCM always recommends validating its model with local data to reflect the actual driving behavior of the region. This study considered work zone capacity as a function of queue discharge rate (QDR), defined as the 15-min average flow rate immediately after breakdown, also known as postbreakdown flow rate. By collecting data from 10 different work zones within the state of Louisiana, the study estimated QDR and its corresponding duration at breakdowns. An average QDR of 1,664 pcphpl and an associated queue of 120 min average duration was found. Analysis of variance showed that average QDRs across all sites were not significantly different. The QDR prediction model revealed that a closed right lane and a work zone on linear roadways significantly increased the discharge rate. However, the presence of nearby exit ramps, daytime scenarios, and an increase in the speed ratio and truck percentages were found to decrease the discharge rate. A separate model for the duration of queue or breakdown found the time of day, change in the speed ratio, presence of entry ramp, location of work zones, and annual average daily traffic of the roadway to be significant variables.

Adaptation of Highway Capacity Manual 2000 for Planning-Level Analysis of Two-Lane and Multilane Highways in Florida

2002 ◽  
Vol 1802 (1) ◽  
pp. 62-68 ◽  
Author(s):  
Scott S. Washburn ◽  
Douglas S. McLeod ◽  
Kenneth G. Courage
Keyword(s):  
Level Of Service ◽  
Highway Capacity ◽  
Intended Application ◽  
Highway Capacity Manual ◽  
Florida Department ◽  
Future Edition ◽  
Software Program ◽  
The Creation ◽  
Level Analysis

A planning-level adaptation was developed of the Highway Capacity Manual (HCM) 2000 procedure for estimating the level of service (LOS) on two-lane and multilane highways in Florida. The problems associated with planning-level adaptations in general and with uninterruptedflow highways in particular were identified. Although much of the adaptation was achieved though the use of default values for data items, some departures from the HCM procedures were required. The most significant deviation was the creation of a third class of two-lane highway to supplement the two classes currently defined in the HCM. A case was made for the existence of this class and its inclusion in a future edition of the HCM. The Florida Department of Transportation’s planning-level methodology, termed HIGHPLAN, is well suited to its intended application, which is planning-level analysis of two-lane and multilane highways in Florida. It maintains fidelity to the HCM procedures to the extent that Florida conditions will allow and Florida users will accept. As long as they are understood, the departures from the HCM should not pose significant problems for users outside of Florida. The planning-level methodology has also been implemented in a software program that produces LOS estimates and service volume tables covering sitespecific conditions.

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