Models for Right-Turn-on-Red and Their Effects on Intersection Delay

1997 ◽  
Vol 1572 (1) ◽  
pp. 131-139 ◽  
Author(s):  
Ghassan Abu-Lebdeh ◽  
Rahim F. Benekohal ◽  
Bashar Al-Omari
Keyword(s):  
Capacity Analysis ◽  
Highway Capacity ◽  
Average Delay ◽  
Highway Capacity Manual ◽  
Turn On ◽  
Significant Difference ◽  
Actual Field ◽  
The Difference ◽  
Exclusive Right ◽  
Delay Difference

Models to estimate right-turn-on-red (RTOR) volumes at intersections with exclusive right-turn (RT) lanes are developed, and the effects of RTOR volumes on computed delay are assessed. The important variables in these models are the RT volume, followed by green-time-to-cycle (G/C) ratio, volume of conflicting traffic, and whether there is a protected phase for opposing left-turning vehicles. The estimated RTOR increased as the RTs increased. However, it decreased as G/C and the volume of conflicting traffic increased. Results show that not accounting for RTOR volumes can lead to a significant difference in delay estimates for RT lanes and, to a lesser extent, on the corresponding approaches. For RT lanes, in one-half of the cases the difference was greater than 5 percent, in more than one-quarter of the cases the difference was greater than 10 percent, and in at least one of eight cases the difference was greater than 20 percent. Differences for individual cases ranged between 0 and 130 percent, with an average of 12 percent. For approaches, the average delay difference was 4 percent, and for individual cases the difference ranged between −2 and 78 percent. As recommended by the Highway Capacity Manual, actual field counts of RTOR volume should be used whenever available. However, in the absence of such counts, the models developed here can be used and hence should be considered in capacity analysis procedures.

Assessment of Arterial Signal Timings Based on Various Operational Policies and Optimization Tools

2021 ◽  
pp. 036119812110111
Author(s):  
Suhaib Al Shayeb ◽  
Nemanja Dobrota ◽  
Aleksandar Stevanovic ◽  
Nikola Mitrovic
Keyword(s):  
Travel Time ◽  
Heavy Traffic ◽  
Future Research ◽  
Signal Timing ◽  
Highway Capacity ◽  
Average Delay ◽  
Highway Capacity Manual ◽  
Simulation And Optimization ◽  
Fort Lauderdale ◽  
Design Engineers

Traffic simulation and optimization tools are classified, according to their practical applicability, into two main categories: theoretical and practical. The performance of the optimized signal timing derived by any tool is influenced by how calculations are executed in the particular tool. Highway Capacity Software (HCS) and Vistro implement the procedures defined in the Highway Capacity Manual, thus they are essentially utilized by traffic operations and design engineers. Considering its capability of timing diagram drafting and travel time collection studies, Tru-Traffic is more commonly used by practitioners. All these programs have different built-in objective function(s) to develop optimized signal plans for intersections. In this study, the performance of the optimal signal timing plans developed by HCS, Tru-Traffic, and Vistro are evaluated and compared by using the microsimulation software Vissim. A real-world urban arterial with 20 intersections and heavy traffic in Fort Lauderdale, Florida served as the testbed. To eliminate any bias in the comparisons, all experiments were performed under identical geometric and traffic conditions, coded in each tool. The evaluation of the optimized plans was conducted based on average delay, number of stops, performance index, travel time, and percentage of arrivals on green. Results indicated that although timings developed in HCS reduced delay, they drastically increased number of stops. Tru-Traffic signal timings, when only offsets are optimized, performed better than timings developed by all of the other tools. Finally, Vistro increased arrivals on green, but it also increased delay. Optimized signal plans were transferred manually from optimization tools to Vissim. Therefore, future research should find methods for automatically transferring optimized plans to Vissim.

scholarly journals Analysis of Component Errors in the Highway Capacity Manual Travel Time Reliability Estimations for Urban Streets

2020 ◽  
Vol 2674 (6) ◽  
pp. 85-97 ◽  
Author(s):  
Ernest O. A. Tufuor ◽  
Laurence R. Rilett
Keyword(s):  
Travel Time ◽  
Time Variability ◽  
Travel Time Reliability ◽  
Travel Times ◽  
Highway Capacity ◽  
Highway Capacity Manual ◽  
Urban Streets ◽  
Estimate Travel Time ◽  
The Difference ◽  
Travel Time Variability

The Highway Capacity Manual 6th edition (HCM6) includes a new methodology to estimate and predict the distribution of average travel times (TTD) for urban streets. The TTD can then be used to estimate travel time reliability (TTR) metrics. Previous research on a 0.5-mi testbed showed statistically significant differences between the HCM6 estimated TTD and the corresponding empirical TTD. The difference in average travel time was 4 s that, while statistically significant, is not important from a practical perspective. More importantly, the TTD variance was underestimated by 70%. In other words, the HCM6 results reflected a more reliable testbed than field measurement. This paper expands the analysis on a longer testbed. It identifies the sources and magnitude of travel time variability that contribute to the HCM6 error. Understanding the potential sources of error, and their quantitative values, are the first steps in improving the HCM6 model to better reflect actual conditions. Empirical Bluetooth travel times were collected on a 1.16-mi testbed in Lincoln, Nebraska. The HCM6 methodology was used to model the testbed, and the estimated TTD by source of travel time variability was compared statistically to the corresponding empirical TTD. It was found that the HCM6 underestimated the TTD variability on the longer testbed by 67%. The demand component, missing variable(s), or both, which were not explicitly considered in the HCM6, were found to be the main source of the error in the HCM6 TTD. A focus on the demand estimators as the first step in improving the HCM6 TTR model was recommended.

Variations in Capacity at Signalized Intersections with Different Area Types

2000 ◽  
Vol 1710 (1) ◽  
pp. 199-204 ◽  
Author(s):  
Xuewen Le ◽  
Jian Lu ◽  
Edward A. Mierzejewski ◽  
Yanhu Zhou
Keyword(s):  
Signalized Intersections ◽  
Capacity Analysis ◽  
Adjustment Factor ◽  
Highway Capacity ◽  
Left Turn ◽  
Highway Capacity Manual ◽  
Central Florida ◽  
Start Up ◽  
Study Results ◽  
Lost Time

The capacity analysis procedure for signalized intersections included in the Highway Capacity Manual (HCM) needs to consider the area type of a given intersection. The area-type adjustment factor used in the procedure is based on conclusions from a limited number of studies. In addition, the procedure for using an area-type adjustment factor is not well defined in the HCM. A study undertaken in central Florida to study the effects of four different area types on the capacity of signalized intersections is summarized. These four area types include recreational, business, residential, and shopping. Study results indicated that differences in saturation headways among different area types were significant. The saturation headways observed in recreational areas were significantly higher than those in other areas for both left-turn and through movements. The through-movement saturation headways obtained in residential, shopping, and business areas were not significantly different. This study resulted in a new area-type adjustment factor of 0.92 for recreational areas, whereas the factor is 1.00 for other areas. Results in this study also indicated that the differences in start-up lost time among different area types were not significantly different. In addition, according to the results of the analysis, 75 percent of the yellow interval in undersaturated conditions and 35 percent of the yellow interval in oversaturated conditions were found to be unused and considered clearance lost time.

Gap Acceptance Capacity for Right Turns at Signalized Intersections

1998 ◽  
Vol 1646 (1) ◽  
pp. 47-53 ◽  
Author(s):  
Mark R. Virkler ◽  
Murli Adury Krishna
Keyword(s):  
Field Study ◽  
Unsaturated Flow ◽  
Signalized Intersections ◽  
Signalized Intersection ◽  
Highway Capacity ◽  
Highway Capacity Manual ◽  
Turn On ◽  
Stop Sign ◽  
Intersection Analysis ◽  
Right Turns

The capacity for right turns into gaps at signalized intersections, through right turn on red (RTOR) and free rights (with yield control), is examined. Current treatments provided by the Highway Capacity Manual (HCM), SIDRA, and a stop sign analogy (SSA) are examined. An adjustment to the SSA to eliminate capacity from gaps greater than the unsaturated flow period of the conflicting traffic is then described. The capacity for right turns into gaps is measured through a field study of seven right-turn-only lanes. The measured capacities are then compared with predicted capacities from the SSA and the adjusted stop sign analogy (ASSA). The data indicate that the HCM procedure to estimate RTOR volumes may not properly estimate those volumes. The SSA procedure tends to overestimate right-turn capacity by ignoring the effect of short phase lengths. The ASSA procedure provides lower estimates of capacity than the SSA, but may underestimate capacity. The results of the study can significantly increase the accuracy and usefulness of signalized intersection analysis by helping to answer questions about right-turn capacity, which now cannot be adequately addressed.

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 ANALISIS KINERJA SIMPANG BERSINYAL BERLENGAN EMPAT

2015 ◽  
Vol 1 (1) ◽  
pp. 69-76
Author(s):  
Mohd Isa T. Ibrahim ◽  
Meliyana Meliyana ◽  
Saifannur Saifannur
Keyword(s):  
Data Collection ◽  
Traffic Flow ◽  
Service Level ◽  
Traffic Volume ◽  
Degree Of Saturation ◽  
Highway Capacity ◽  
Average Delay ◽  
Highway Capacity Manual ◽  
The North ◽  
High Traffic Volume

Simpang Surabaya is one of the intersections that have high traffic volume. Problems that occur in Simpang Surabaya is the density of traffic flow at peak hours. The objective of  this studyis to analyze the performance of four approaches intersection with traffic signals.Video camera was installed in the data collection then  analyze with Indonesian Highway Capacity Manual (MKJI). The result showed that  at peak hour the highest flow  on the North approache, South approache, East approache, and West approaches respectively 1135 smp hour, 2218 smp hour, 863 smp/hour and 1517 smp hour. Capacity of existing condition in North approache, South approache, East approache, and West approache respectively by 1436 smp/hour, 2806 smp/ hour, 1092 smp/ hour  and 1920 smp/hour. The degree of saturation of each approache is 0.79 and the average delay is 44.92 sec / smp. Based on the results obtained, the Simpang Surabaya is at the service level D.

scholarly journals Multi Vehicle-Type Right Turning Gap-Acceptance and Capacity Analysis at Uncontrolled Urban Intersections

2018 ◽  
Vol 48 (2) ◽  
pp. 99-108 ◽  
Author(s):  
Doddapaneni Abhigna ◽  
Dipak P. Brahmankar ◽  
Kodavanti Venkata Raghavendra Ravishankar
Keyword(s):  
Capacity Analysis ◽  
Vehicular Traffic ◽  
Gap Acceptance ◽  
Highway Capacity ◽  
Highway Capacity Manual ◽  
Vehicle Type ◽  
Traffic Stream ◽  
Critical Zones ◽  
The Right

Intersections are the critical zones where conflicting, merging and diverging movements influence the intersection capacity. Uncontrolled intersections in particular pose dangerous situations to vehicular traffic. During peak vehicular flow, the unpredictable crossing behavior of minor stream vehicles induces delay and reduces the capacity of the intersection. Capacity at uncontrolled intersections is typically measured either by gap acceptance method, empirical regression approaches and conflict technique. Gap acceptance is an important characteristic for analyzing uncontrolled intersections. The behavior of different vehicle types and gap of subject vehicle type from minor street taking right turn to merge with major traffic stream is analyzed using gap acceptance method. The objective of the current study is to analyze the effect of major stream vehicle type combinations on the minor stream vehicle gap-acceptance behavior and to determine the capacity of the minor stream taking into account the influence of the right turning vehicles. The capacity of minor stream calculated using Highway Capacity Manual (HCM) 2010, Luttenin’s model, and Tanner’s model are compared. It is observed that two wheelers are more aggressive than three wheelers for most of the major stream vehicular combinations observed in this study.

Generalized Delay Model for Signalized Intersections and Arterial Streets

1997 ◽  
Vol 1572 (1) ◽  
pp. 112-121 ◽  
Author(s):  
Daniel B. Fambro ◽  
Nagui M. Rouphail
Keyword(s):  
Performance Measure ◽  
Signalized Intersections ◽  
Level Of Service ◽  
Delay Model ◽  
Highway Capacity ◽  
Average Delay ◽  
Variable Demand ◽  
Highway Capacity Manual ◽  
Arterial Streets ◽  
Proposed Model

Average delay per vehicle is the primary measure for determining the level of service at signalized intersections. This performance measure is also a major component in the calculation of average travel speed used to determine the level of service on arterial streets. The most widely used models for estimating delay at signalized intersections are those in Chapters 9 ("Signalized Intersections") and 11 ("Urban and Suburban Arterials") of the Highway Capacity Manual. This research reviewed the literature on models for estimating delay at signalized intersections to identify limitations and formulate revised models to address those limitations. Specific problems that were addressed included the inability to account for actuated-control parameters, oversaturation and variable demand, and metering and filtering by upstream traffic signals. The research team developed a generalized delay model to address these limitations and then validated the generalized model with both field and simulation data. The proposed model is sensitive to actuated-control parameter settings, oversaturation and variable demand conditions, and filtering and metering effects of upstream signals. The proposed model is also a good predictor of delays observed in the field and estimated by microscopic traffic simulation programs for the conditions studied. The generalized delay model is recommended for inclusion in future editions of the Highway Capacity Manual.

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