Queuing and Natural Diversion at Short-Term Freeway Work Zone Lane Closures

1996 ◽  
Vol 1529 (1) ◽  
pp. 19-26 ◽  
Author(s):  
Gerald L. Ullman
Keyword(s):  
High Volume ◽  
Field Studies ◽  
Operating Conditions ◽  
Work Zone ◽  
Temporary Work ◽  
Short Term ◽  
Traffic Conditions ◽  
Traffic Stream ◽  
Traffic Volumes ◽  
Lane Closures

Research conducted to explore the effects of natural diversion on traffic conditions and travel patterns upstream of temporary work zone lane closures on high-volume urban freeways in Texas is described. Specific objectives were to explore how natural diversion affects traffic volumes at the exit and entrance ramps upstream of the lane closures and the interrelationships between the freeway and frontage road operating conditions that develop at a closure and the amount of natural diversion that occurs. The field studies showed that the rate of queue growth upstream of the short-term lane closures diminished significantly after the first hour at each site. Eventually, the queues approached a balanced state in which the upstream end of the queue became almost stationary. This stabilization was due to significant reductions in entrance ramp volumes both upstream of the freeway queue and within the limits of queuing, as well as to changes in exit ramp volumes within the queue. As a result of these ramp volume changes the constrained flow rate within the queue increased as a function of the distance upstream of the actual lane closure. Using the theory of shock waves in a traffic stream it was shown that the changes in ramp volumes and resulting impact on constrained freeway flow rates within the queue were consistent with the queue stabilization process observed at each site.

Field Evaluation of Late Merge Traffic Control in Work Zones

2005 ◽  
Vol 1911 (1) ◽  
pp. 33-41 ◽  
Author(s):  
Andrew G. Beacher ◽  
Michael D. Fontaine ◽  
Nicholas J. Garber
Keyword(s):  
Field Test ◽  
Traffic Control ◽  
Positive Response ◽  
Field Evaluation ◽  
Field Studies ◽  
Work Zone ◽  
Work Zones ◽  
Short Term ◽  
Term Field ◽  
Lane Closures

The traffic control strategy of the late merge in work zones was devised to improve flow and safety at work zone lane closures. Although some states have put the strategy into practice, only a handful of short-term field studies have formally evaluated its effectiveness. Additional field studies were necessary to assess the efficacy of the strategy and its proper deployment. This paper documents the results of a field test of the late merge traffic control conducted over several months. The late merge strategy was evaluated by comparing its effectiveness with that of traditional plans for work zone lane closures. The field test was conducted on a primary route in Tappahannock, Virginia, at a two-to-one lane closure. Results showed that throughput increased, but the increase was not statistically significant. Likewise, time in queue decreased, but the decrease was not statistically significant. These results were much less dramatic than those of other studies. Possible reasons for this disparity include different driver populations, road types, vehicle mixes, and site-specific characteristics. Despite limited improvements in throughput and time in queue, more drivers were in the closed lane, a positive response to the late merge signs.

Theoretical Approach to Predicting Traffic Queues at Short-Term Work Zones on High-Volume Roadways in Urban Areas

2003 ◽  
Vol 1824 (1) ◽  
pp. 29-36 ◽  
Author(s):  
Gerald L. Ullman ◽  
Conrad L. Dudek
Keyword(s):  
Theoretical Approach ◽  
Urban Areas ◽  
High Volume ◽  
Work Zone ◽  
Primary Data ◽  
Short Term ◽  
Rational Representation ◽  
Traffic Volumes ◽  
New Perspective ◽  
Road Work

A new theoretical approach is described that more accurately predicts the length of queues that will develop when one or more lanes are closed for short-term freeway road work in an urban area. A model was developed that represents the interactions between diversion and traffic queuing on the freeway. The model is based on macroscopic fluid-flow analogies of traffic and a new perspective of the freeway corridor as a section of permeable pipe. Historical traffic volumes on the roadway serve as the primary data input into the model. Unlike other work zone analysis methods, the model presents a rational representation of how traffic queues stabilize upstream of temporary work zone bottlenecks in urban areas. The model can be calibrated to reasonably represent the magnitude of traffic queues developing upstream of actual work zone lane closures on urban freeways in Texas.

Evaluation of Interstate Highway Capacity for Short-Term Work Zone Lane Closures

2004 ◽  
Vol 1877 (1) ◽  
pp. 85-94 ◽  
Author(s):  
Wayne A. Sarasua ◽  
William J. Davis ◽  
David B. Clarke ◽  
Jayaram Kottapally ◽  
Pawan Mulukutla
Keyword(s):  
Work Zone ◽  
Short Term ◽  
Highway Capacity ◽  
Interstate Highway ◽  
Lane Closures

Effect of the Work Zone Double-Fine Law in Texas

2000 ◽  
Vol 1715 (1) ◽  
pp. 24-29 ◽  
Author(s):  
Gerald L. Ullman ◽  
Paul J. Carlson ◽  
Nada D. Trout
Keyword(s):  
Public Safety ◽  
Field Studies ◽  
Work Zone ◽  
Work Zones ◽  
Citation Data ◽  
Short Term ◽  
Texas Department ◽  
Before And After ◽  
The Law ◽  
External Reasons

Results of research conducted to investigate the short-term effects of the double-fine law in work zones implemented in Texas on January 1, 1998, are presented. Field studies of traffic speeds in several work zones were performed before and after the law was implemented. Traffic citation data for these same work zones were also obtained from the Texas Department of Public Safety. Analyses showed that traffic speeds in the work zones 4 to 6 months after the law was enacted were essentially unchanged from before the law was enacted. Similarly, citation frequency and fines levied were not significantly higher than they were before enactment of the law. The data suggested that a higher proportion of drivers who were issued citations after the law was implemented chose to take defensive driving training and to have the ticket subsequently dismissed. However, researchers could not determine whether this was due to the increased fine or to other external reasons.

Estimating Interstate Highway Capacity for Short-Term Work Zone Lane Closures

2006 ◽  
Vol 1948 (1) ◽  
pp. 45-57 ◽  
Author(s):  
Wayne A. Sarasua ◽  
William J. Davis ◽  
Mashrur A. Chowdhury ◽  
Jennifer H. Ogle
Keyword(s):  
Work Zone ◽  
Short Term ◽  
Highway Capacity ◽  
Interstate Highway ◽  
Lane Closures

scholarly journals Incorporating Practical Degree of Saturation in Capacity Estimation of On-Street, Mid-Block, Off-Line Bus Stops

2021 ◽  
pp. 036119812110241
Author(s):  
Faheema Hisham ◽  
Jonathan M. Bunker ◽  
Ashish Bhaskar
Keyword(s):  
Failure Rate ◽  
Waiting Times ◽  
High Volume ◽  
Operating Conditions ◽  
Degree Of Saturation ◽  
Traffic Conditions ◽  
Bus Stop ◽  
Transit Capacity ◽  
Bus Stops

The effectiveness of an on-street bus facility depends on the general traffic that shares the lane used by buses. The Transit Capacity and Quality of Service Manual (TCQSM) methodology was used to estimate facility bus capacity based on critical stop operation. Hisham et al. provided an improved understanding of performance of an on-street, mid-block, off-line bus stop by relating bus stop capacity to the adjacent lane traffic flow rate. Using the TCQSM methodology, bus stop capacity was determined by adopting an estimated operation margin that relates to a design bus stop failure rate. However, failure rate is theoretically ambiguous and difficult to quantify in practice, particularly under high volume traffic conditions. In contrast, degree of saturation is a direct measure of operating conditions experienced by buses using the stop, and by the adjacent lane general traffic, so it directly affects approach delay and queuing. The aim of this study was to better understand performance at on-street, mid-block, off-line bus stops by considering degrees of saturation of loading areas and the adjacent lane rather than design failure rate according to the TCQSM methodology, and to ensure that waiting times upstream of bus stops are kept to acceptable levels by determining bus stop maximum working capacity.

Two-Level Signalized Intersection

2008 ◽  
Vol 2060 (1) ◽  
pp. 53-64 ◽  
Author(s):  
Eon Kyo Shin ◽  
Jang Hee Lee ◽  
Ju Hyun Kim ◽  
Jung Sik Kim ◽  
Yong Woo Jeong
Keyword(s):  
Traffic Congestion ◽  
Single Point ◽  
High Volume ◽  
Complete Separation ◽  
Signalized Intersection ◽  
Traffic Conditions ◽  
Delay Times ◽  
Traffic Volumes ◽  
New Type ◽  
Intersection Types

Severe traffic congestion often occurs at intersections of high-volume traffic arteries. To reduce this congestion, innovative intersection designs such as the single-point urban interchange (SPUI), center-turn overpass (CTO), and echelon interchange (EI) have been implemented. This paper introduces a new type of intersection, the two-level signalized intersection (TLSI), which improves the efficiency of intersection operations under a wide variety of traffic conditions. The paper compares the TLSI with other innovative intersection types. Unlike the SPUI, CTO, or EI, the TLSI provides for complete separation of east–west and north–south traffic. The TLSI also enables the use of directional separation and leading, lagging, or overlapping lefts on both upper and lower levels. Simulation results indicate that, compared with these other innovative intersection types, the TLSI has the shortest delay times in most evaluation scenarios as well as the least sensitivity to variations in traffic volume. However, the TLSI shows significant delay when traffic volumes on the major and minor roads are vastly different.

Validation of On-line Respiration Meter and its Applications by Computer Simulation

1992 ◽  
Vol 26 (5-6) ◽  
pp. 1355-1363 ◽  
Author(s):  
C-W. Kim ◽  
H. Spanjers ◽  
A. Klapwijk
Keyword(s):  
Steady State ◽  
Activated Sludge ◽  
Respiration Rate ◽  
Oxygen Demand ◽  
Operating Conditions ◽  
Mass Balances ◽  
Short Term ◽  
Respiration Rates ◽  
On Line ◽  
Made In

An on-line respiration meter is presented to monitor three types of respiration rates of activated sludge and to calculate effluent and influent short term biochemical oxygen demand (BODst) in the continuous activated sludge process. This work is to verify if the calculated BODst is reliable and the assumptions made in the course of developing the proposed procedure were acceptable. A mathematical model and a dynamic simulation program are written for an activated sludge model plant along with the respiration meter based on mass balances of BODst and DO. The simulation results show that the three types of respiration rate reach steady state within 15 minutes under reasonable operating conditions. As long as the respiration rate reaches steady state the proposed procedure calculates the respiration rate that is equal to the simulated. Under constant and dynamic BODst loading, the proposed procedure is capable of calculating the effluent and influent BODst with reasonable accuracy.

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