Field Evaluation of Highway Capacity Manual 2000 Analysis Procedures for Two-Lane Highways

2002 ◽  
Vol 1802 (1) ◽  
pp. 125-132 ◽  
Author(s):  
Michael P. Dixon ◽  
Satya Sai Kumar Sarepali ◽  
Kevin Allen Young
Keyword(s):  
Simulation Model ◽  
Field Data ◽  
Field Evaluation ◽  
Analysis Procedure ◽  
Highway Capacity ◽  
Highway Capacity Manual ◽  
Percent Time ◽  
Percent Time Spent Following ◽  
Northern Idaho ◽  
Rural Highway

Highway Capacity Manual (HCM) 2000 two-lane rural highway directional, two-way, and passing-lane analysis procedures based on field data and simulation were evaluated. Detailed field data were collected from two highway sections in northern Idaho, one with and one without passing lanes. The TWOPAS simulation model was used to provide additional insights. Particular attention was given to the differences in estimates for percent time spent following (PTSF) produced by the twoway and directional analysis procedures. It was found that the two-way analysis procedure was more accurate, although both procedures produced estimates that were too high. The passing-lane analysis procedure was also evaluated, and the HCM 2000 procedure was found to be conservative in its estimates of PTSF reductions due to a passing lane.

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 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

Evaluating new methodologies for estimating performance on two-lane highways

2008 ◽  
Vol 35 (8) ◽  
pp. 777-785 ◽  
Author(s):  
Ahmed Al-Kaisy ◽  
Casey Durbin
Keyword(s):  
National Research Council ◽  
Highway Capacity ◽  
Highway Capacity Manual ◽  
Percent Time ◽  
Moving Vehicles ◽  
Study Results ◽  
New Methodologies ◽  
Analytical Procedures ◽  
Percent Time Spent Following ◽  
Study Sites

This paper examines two new methodologies for field estimation of percent time spent following (PTSF) on two-lane highways. Using speed and time headway data, the two methodologies estimate the percentage of vehicles trapped in platoons, unable to pass slow-moving vehicles. A total of 236 h of field data, including individual speeds and headways, were collected at three study sites in the state of Montana. The study examined the sensitivity of PTSF estimates to some important platooning variables. The study also included a comparison of PTSF estimates from the new methods versus those found using the current United States National Research Council Highway capacity manual (HCM) analytical procedures. Study results showed that the two new methodologies were successful in capturing the effect of platooning variables on PTSF estimates and outperformed the HCM procedures in this regard. Further, the results strongly attest to the promise of the proposed methods in advancing the current analytical procedures for estimating performance on two-lane highways.

scholarly journals Operational Considerations of Passing Zones for Two-lane Highways: Spanish Case Study

2018 ◽  
Vol 30 (5) ◽  
pp. 601-612
Author(s):  
Ana Tsui Moreno ◽  
Carlos Llorca ◽  
Scott S. Washburn ◽  
Jose Elievam Jr. Bessa ◽  
Alfredo Garcia
Keyword(s):  
Road Segment ◽  
Highway Capacity ◽  
Zone Length ◽  
Highway Capacity Manual ◽  
The Road ◽  
Percent Time ◽  
Analysis Methodology ◽  
Percent Time Spent Following ◽  
Traffic Operation

The U.S. Highway Capacity Manual (HCM 2010) methodology is used in Spain to evaluate traffic operation and quality of service. In two-lane undivided highways, the effect of limiting where drivers could pass slower vehicles, or passing restrictions, is considered through the percentage of no-passing zones. This measure does not account for how passing opportunities are distributed along the road. The objective of this research was to evaluate the effect percentage of no-passing zones and average passing zone length on a two-lane highway and, if significant, incorporate them in the analysis methodology,. The TWOPAS microsimulation program was calibrated and validated to the Spanish conditions. Passing restrictions had little effect on average traffic speed (ATS), with differences lower than 6 km/h between a road segment with no passing restrictions and a road segment with a passing restriction on 100% of its length. Conversely, passing restrictions can increase the percent time spent following (PTSF) up to 30%. Increasing the passing zone length beyond 2,000 m does not improve PTSF. The new models could be used to better estimate traffic operation on Spanish two-lane highways.

Review of Percent Time Spent Following (PTSF) as Performance Measure for Two-lane Highways

2013 ◽  
Vol 64 (1) ◽  
Author(s):  
Muttaka Na'iya Ibrahim ◽  
Othman Che Puan ◽  
Mushairry Mustaffar
Keyword(s):  
Empirical Studies ◽  
Measurement Model ◽  
Performance Measure ◽  
Highway Capacity ◽  
Highway Capacity Manual ◽  
Percent Time ◽  
Surrogate Measure ◽  
Analytical Procedures ◽  
Percent Time Spent Following ◽  
Related Measure

The Highway Capacity Manual (HCM) uses Percent Time Spent Following (PTSF) as key service measure for assessing the level of service of two-lane highways. However, the indicator is difficult to measure directly in the field. For this reason, its estimation to date has been based on analytical procedures using equations derived from simulations and field observations at representative location based on surrogate measure; as the percent of vehicles traveling with headway less than 3 seconds (3 s). Findings from empirical studies confirmed that the HCM analytical procedures used in estimating PTSF yield results that are inconsistent with the 3 s surrogate measure and mostly overestimate the indicator. This paper presents a review on the estimation of PTSF on two-lane highways and suggests probable approach to substantiate the application of the current practice. Further, the authors of this paper argued that the use of 3 s as surrogate for estimating PTSF based on field observation at a specific point may not represent the actual time spent following over a long segment of two-lane highway since PTSF is space related measure. Hence, the authors suggest the use of test vehicle approach over the highway segment to be evaluated to identify the variables that are required for the development of a representative PTSF measurement model. It is expected that this review and suggestion offered will contribute in advancing performance analysis of two-lane highways. 

Validation Results for Four Models of Oversaturated Freeway Facilities

2000 ◽  
Vol 1710 (1) ◽  
pp. 161-170 ◽  
Author(s):  
Fred L. Hall ◽  
Loren Bloomberg ◽  
Nagui M. Rouphail ◽  
Brian Eads ◽  
Adolf D. May
Keyword(s):  
Field Data ◽  
Simulation Models ◽  
Highway Capacity ◽  
Highway Capacity Manual

Some researchers have noted that the current procedures in the Highway Capacity Manual (HCM) may not be appropriate for analyzing complex or oversaturated freeway facilities. The results of a comparison of an HCM-based procedure with field data from six such freeway sites are reported. Because simulation has often been suggested as an alternative to the HCM for oversaturated freeway facilities, three simulation models (CORSIM, FREQ, and INTEGRATION) were also used to analyze these same six sites. The results suggest that the HCM-based procedures do as well as the three simulation models in reproducing the average speeds across the freeway facilities.

Validation of Generalized Delay Model for Vehicle-Actuated Traffic Signals

1997 ◽  
Vol 1572 (1) ◽  
pp. 105-111 ◽  
Author(s):  
Nagui M. Rouphail ◽  
Mohammad Anwar ◽  
Daniel B. Fambro ◽  
Paul Sloup ◽  
Cesar E. Perez
Keyword(s):  
North Carolina ◽  
Field Data ◽  
Traffic Signals ◽  
Signalized Intersections ◽  
Delay Model ◽  
Highway Capacity ◽  
Generalized Model ◽  
Highway Capacity Manual ◽  
Traffic Volumes ◽  
Isolated Intersection

One limitation of the Highway Capacity Manual (HCM) model for estimating delay at signalized intersections is its inadequate treatment of vehicle-actuated traffic signals. For example, the current delay model uses a single adjustment for all types of actuated control and is not sensitive to changes in actuated controller settings. The objective in this paper was to use TRAF-NETSIM and field data to evaluate a generalized delay model developed to overcome some of these deficiencies. NETSIM was used to estimate delay at an isolated intersection under actuated control, and the delay values obtained from NETSIM were then compared with those estimated by the generalized delay model. In addition, field data were collected from sites in North Carolina, and delays observed in the field were compared with those estimated by the generalized delay model. The delays estimated by the generalized model were comparable with the delays estimated by NETSIM. The data compared favorably for degrees of saturation of less than 0.8. However, at higher degrees of saturation, the generalized model produced delays that were higher than NETSIM’s. Some possible explanations for this discrepancy are discussed. The delays estimated by the generalized model were comparable with delays observed in the field. Researchers have concluded that the generalized delay model is sensitive to changes in traffic volumes and vehicle-actuated controller settings and that the generalized delay model is much improved over the current HCM model in estimating delay at vehicle-actuated traffic signals.

Accounting for Nonrandom Arrivals in Estimate of Delay at Signalized Intersections

1996 ◽  
Vol 1555 (1) ◽  
pp. 9-16 ◽  
Author(s):  
Janice Daniel ◽  
Daniel B. Fambro ◽  
Nagui M. Rouphail
Keyword(s):  
Field Data ◽  
Empirical Studies ◽  
Primary Objective ◽  
Signalized Intersections ◽  
Degree Of Saturation ◽  
Delay Model ◽  
Highway Capacity ◽  
Highway Capacity Manual ◽  
Research Show

The primary objective of this research was to determine the effect of nonrandom or platoon arrivals on the estimate of delay at signalized intersections. The delay model used in the 1994 Highway Capacity Manual (HCM) accounts for nonrandom arrivals through the variable m, which can be shown to be equal to 8kI, where k describes the arrival and service distributions at the intersection and I describes the variation in arrivals due to the upstream intersection. The 1994 HCM delay model m-values are a function of the arrival type, where the arrival type describes the quality of progression at the intersection. Although an improvement to the fixed k I-value used in the 1985 delay model, the 1994 m values are based on empirical studies from limited field data and do not account for the decrease in random arrivals as the volume approaches capacity at the downstream intersection. This research provides an estimate of the variable kI for arterial conditions. An analytical equation was developed as a function of the degree of saturation, and a separate equation was developed for each signal controller type. The results from this research show that the proposed kI's provide delay estimates closer to the measured delay compared with the delay estimates using the kI-values in the 1994 HCM delay model.

Validation of Generalized Delay Model for Oversaturated Conditions

1997 ◽  
Vol 1572 (1) ◽  
pp. 122-130 ◽  
Author(s):  
Roelof J. Engelbrecht ◽  
Daniel B. Fambro ◽  
Nagui M. Rouphail ◽  
Aladdin A. Barkawi
Keyword(s):  
Simulation Model ◽  
Close Agreement ◽  
Signalized Intersections ◽  
Delay Model ◽  
Traffic Operations ◽  
Microscopic Simulation ◽  
Highway Capacity ◽  
Traffic Demand ◽  
Highway Capacity Manual ◽  
The U.S

With today’s ever-increasing traffic demand, more and more signalized intersections are experiencing congestion for longer periods of time. To better quantify oversaturated conditions, it is necessary to accurately estimate oversaturation delay. The generalized delay model, proposed for inclusion in the next update of the U.S. Highway Capacity Manual (HCM), is introduced here. The generalized delay model differs from the model in the 1994 edition of the HCM as it is sensitive to the duration of the analysis period and is not restricted to degrees of saturation less than 1.2. The TRAF-NETSIM microscopic simulation model was used to verify the generalized delay equation for oversaturated conditions. A simulation model was used, because it is extremely difficult to measure oversaturated delay in the field. The study was designed to cover as much of the domain of oversaturated traffic operations as possible. The variability in simulated delays was investigated, and an equation was developed to predict the standard deviation of oversaturated delay estimates. It was found that delays estimated by the proposed generalized delay model are in close agreement with those simulated by TRAF-NETSIM. On average, simulated delays are overestimated slightly, but the error is small compared with actual delays. The proposed generalized delay model is expected to provide a good estimate of actual oversaturation delays that occur in the field.

Improved Speed-Flow Relationships for Planning Applications

1997 ◽  
Vol 1572 (1) ◽  
pp. 18-23 ◽  
Author(s):  
Alexander Skabardonis ◽  
Richard Dowling
Keyword(s):  
Field Data ◽  
Air Pollutant ◽  
Pollutant Emissions ◽  
Speed Estimation ◽  
Highway Capacity ◽  
Estimation Techniques ◽  
Highway Capacity Manual ◽  
Planning Models ◽  
Speed Flow ◽  
Simulation Results

Improved speed-estimation techniques for planning applications were developed and tested. Comparisons with field data and simulation results indicate that the recommended techniques provide better accuracy and consistency with the procedures contained in the 1994 update of the Highway Capacity Manual. These speed-estimation techniques will improve the accuracy of long-range transportation planning models for predicting travel time, delay, and air-pollutant emissions.

Sign in / Sign up

Export Citation Format

Share Document