Updated Short-term Freeway Work Zone Lane Closure Capacity Values

Updated Short-term Freeway Work Zone Lane Closure Capacity Values
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.

Freeway Work Zone Lane Capacity

Freeway Work Zone Lane Capacity
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.

Capacity and Road User Cost Analysis of Selected Freeway Work Zones in Texas

Capacity and Road User Cost Analysis of Selected Freeway Work Zones in Texas
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.

Effects of Road Construction Intensity and Operations on Rural Freeway Work Zone Capacity

Effects of Road Construction Intensity and Operations on Rural Freeway Work Zone Capacity
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.