Freeway Work Zone Lane Capacity
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Author | : Raymond A. Krammes |
Publisher | : |
Total Pages | : 44 |
Release | : 1992 |
Genre | : Express highways |
ISBN | : |
Recommendations on estimating the capacity of short-term freeway work zone lane closures are presented. The recommendations are based upon 45 hours of capacity counts at 33 different work zones between 1987 and 1991. These new data indicate average capacities for short-term freeway work zone lane closures from 3 to 1 lanes and from 2 to 1 lanes that are significantly higher than older values reported in the 1985 Highway Capacity Manual. A base capacity value of 1,600 pcphpl is recommended for all short-term freeway work zone lane closure configurations.
Author | : Alex Drakopoulos |
Publisher | : |
Total Pages | : 121 |
Release | : 2009 |
Genre | : Traffic safety |
ISBN | : |
The focus of this report is a capacity analysis of two long-term urban freeway Work Zones. Work Zone #1 tapered four mainline lanes to two, using two separate tapers; Work Zone #2 tapered two mainline lanes to one. Work Zone throughput was analyzed throughout the day over multiple days and traffic operations conditions were analyzed up to a distance of five miles upstream of the Work Zone entrance. Historical data from pavement-embedded detectors were used to analyze traffic conditions. The database consisted of five-minute volume, speed and occupancy data collected from 78 detectors for a total of 50 days. Congestion during each analyzed Work Zone existed for more than fourteen hours each day; Work Zone impacts adversely affected freeway operations over distances of 3.7 to 4.2 miles. Speed and occupancy conditions further upstream were, however, not affected, or even improved due to significant trip diversion. Work Zone capacity was defined based on the maximum traffic flows observed over a one-hour period; throughput values were also compiled over longer periods of time when traffic was within 90% of the maximum observed one-hour flows, as well as over the multi-hour mid-day period. The Highway Capacity Manual freeway capacity definition based on the maximum observed 15-min period was not used, since it would have no practical application in estimating Work Zone throughput when congested conditions prevail for the majority of the hours of the day. Certain noteworthy changes took place for the duration of the analyzed Work Zones: per-lane throughput dropped; morning peak periods started earlier, evening peak periods ended later and lasted longer; mid-day volumes dropped accompanied by the highest occupancies of the day. Trip diversion was evident in lower volumes entering the analyzed freeway corridor, higher volumes using off-ramps and lower volumes using onramps upstream of the Work Zones. The majority of diverted traffic comprised smaller vehicles (vehicles up to 21 feet in length); combination truck volumes increased and their use of the median lane increased, contrary to smaller vehicles that shifted toward a heavier use of the shoulder lane.
Author | : |
Publisher | : |
Total Pages | : 216 |
Release | : 2009 |
Genre | : Highway capacity |
ISBN | : |
Author | : |
Publisher | : |
Total Pages | : 246 |
Release | : 2007 |
Genre | : Highway capacity |
ISBN | : |
Author | : Raymond A. Krammes |
Publisher | : |
Total Pages | : 30 |
Release | : 1994 |
Genre | : Express highways |
ISBN | : |
Author | : Ronaldo Luna |
Publisher | : |
Total Pages | : 0 |
Release | : 2014 |
Genre | : |
ISBN | : |
Capacity is affected by construction type and its intensity on adjacent open traffic lanes. The effect on capacity is a function of vehicles moving in and out of the closed lanes of the work zone, and the presence of heavy construction vehicles. Construction activity and its intensity, however, are not commonly considered in estimating capacity of a highway lane. The main purpose of this project was to attempt to quantify the effects of construction type and intensity (e.g. maintenance, rehabilitation, reconstruction, and milling) on work zone capacity. The objective of this project is to quantify the effects of construction type and its intensity on work zone capacity and to develop guidelines for MoDOT to estimate the specific operation type and intensity that will improve the traffic flow by reducing the traffic flow and queue length commonly associated with work zones. Despite the effort put into field data collection, the data collected did not show a full speed-flow chart therefore extracting a reliable capacity value was difficult. A statistical comparison between the capacity values found in this study using either methodologies indicates that there is an effect of construction activity on the values work zone capacity. It was found that the heavy construction activity reduces the capacity. It is very beneficial to conduct similar studies on the capacity of work zone with different lane closure barriers, which is also directly related to the type of work zone being short-term or long-term work zones. Also, the effect of different geometric and environmental characteristics of the roadway should be considered in future studies.
Author | : Wayne A. Sarasua |
Publisher | : |
Total Pages | : 78 |
Release | : 2005 |
Genre | : Highway capacity |
ISBN | : |
Author | : |
Publisher | : |
Total Pages | : 258 |
Release | : 2003 |
Genre | : Highway capacity |
ISBN | : |
Author | : Darrell W. Borchardt |
Publisher | : |
Total Pages | : 68 |
Release | : 2009 |
Genre | : Cost effectiveness |
ISBN | : |
This research was developed to produce usable and meaningful estimates for work zone capacities under a variety of roadway and traffic conditions, work zone configurations, and lane closure scenarios within Texas. Using data collected at eighteen work zone sites, the research presents updated guidance for expected capacities of various freeway work zone lane closure configurations. In addition, models used to evaluate traffic conditions in work zones were evaluated and recommendations for their use were made. Finally, recommendations concerning road user cost analysis for freeway construction projects are included.
Author | : Hojjat Adeli |
Publisher | : |
Total Pages | : 256 |
Release | : 2004 |
Genre | : Highway capacity |
ISBN | : |
Periodic resurfacing, rehabilitation, restoration, and reconstruction work is needed on the aging highway system to maintain a desired level of service for the traveling public. However, temporary work zones on highways disrupt the normal flow of traffic and reduce the level of service. Freeway work zones have become a major source of traffic congestion and travelers' delays which result in reduced freeway capacity, increased driver frustration, increased traffic accidents, increased road user delay cost, and increased fuel consumption and vehicle emissions. In this research, scientific models have been created for estimation of the work zone capacity for the first time. A case-based reasoning (CBR) model has been created for freeway work zone traffic management considering work zone layout, traffic demand, work characteristics, traffic control measures, and mobility impacts. A freeway work zone traffic delay and cost optimization model has been developed in terms of the length of the work zone segment and the starting time of the work zone using average hourly traffic data. An adaptive computational model has been created for estimating the work zone capacity and queue length and delay. A neuro-fuzzy logic model has been developed for estimation of the freeway work zone capacity taking into account 17 different factors impacting the work zone capacity. An object-oriented model has been developed for freeway work zone capacity and queue delay and length estimation. The model has been implemented into an interactive software system, called IntelliZone. IntelliZone's capacity estimation engine is based on pattern recognition and neural network models incorporating a large number of factors impacting the work zone capacity. This research provides the foundation for a new generation of advanced decision support systems for effective management of traffic at work zones. The extensive parametric study of main factors impacting the work zone capacity provides quantitative and objective results of value to work zone engineers and highway agencies when creating traffic management plans for work zones.