The New York State Department of Transportation (NYSDOT) places a high priority on the safety of workers and the traveling public in the management of its capital construction and maintenance programs. Minimizing traffic congestion and adverse impacts on the local community, including environmental impacts, also are important considerations. To support these objectives, work-zone traffic control is an integral element in the management of department programs.
Work-zone management is composed of several distinct elements. Among them are: establishment of overall goals and objectives; development of standards and specifications; provision of project-specific traffic control plans; providing staff training and development; contractor/industry outreach; maintaining an accident reporting and analysis system; and maintaining an ongoing traffic control quality assurance program.
The purpose of the program is to gather information to evaluate the overall quality and effectiveness of work-zone traffic control throughout the department, to identify areas where improvement is needed and to facilitate open discussion of traffic control issues.
The work-zone inspection procedure involves an on-site inspection of a sample of projects in each of NYSDOT’s 11 regions.
The inspection is conducted state-wide each year during the peak of construction season (June through October). This helps ensure that adequate work is under way to provide an acceptable sample size and that construction projects are fully active at the time of inspection. For construction, the sample typically includes at least 25% of the projects active at the time of inspection. The goal is to inspect at least 10 projects, although the actual sample varies from as few as eight to nearly 20 in the largest regions.
The construction sample is selected in advance by the main office team. This may not be a truly random sample, but the team members are generally not familiar with project status and thus do not bias selection in favor of good or poor projects. The intention is to select a range of characteristics that provide a representative sample of work active at that time.
Each of the 11 regions is scheduled separately, with a week set aside for each. Typically, two inspection days are scheduled in each region, one for construction projects and one for maintenance activities. Permit activities are covered as they are encountered. For regions with very large programs, an extra half or full day may be added. In addition, time is allotted at night to conduct partial inspections of a limited number of sites to observe night performance of traffic control devices. If night work is active in the region, time also is allotted for inspections when that work is active.
Maintenance work activities are typically not scheduled far in advance. Therefore, each region compiles a list of maintenance work active on the day of the inspection.
The inspection team selects sites to be inspected at the start of the day, with the goal of obtaining a representative sample that economizes on travel time and distance. The list typically includes larger work activities, with minor activities added as encountered.
Inspection teams consist of four to six members, with Main Office Construction Division and Traffic and Safety Division representatives forming the nucleus of the team. A representative from the Federal Highway Administration Division Office with extensive work-zone expertise joins the group several times each year. This participation adds technical expertise, as well as providing an independent perspective to the procedure. A representative of the Transportation Maintenance Division participates in many of the inspections, at least for maintenance projects, and regions are assigned two or three representatives. The Regional Traffic and Safety groups coordinate work-zone traffic control in the regions and typically provide one team member. Other team members include regional construction, design or maintenance groups and the Regional Safety and Health representatives.
Early experience indicated that a four-member team was advantageous in terms of logistics and in holding to one focused discussion during inspections. Additional members make it more difficult to maintain one focused discussion, but the larger team provides several advantages. It permits broader participation in the process, and because more program areas can be involved there is better buy-in into the process and the results. Additional members also provide more technical expertise and a broader range of experience.
Following completion of each inspection a debriefing meeting is held with regional staff providing a preliminary discussion of the results.
The ratings game
Inspections consist of a drive-through of each project with information and comments recorded on standard forms and an overall quality rating assigned.
The form records descriptive information about the project and the temporary traffic controls observed and lists types of devices and safety features encountered and their condition and effectiveness. Features are listed in six broad categories: construction signing/advance warning; channelization; pavement markings; flagging; roadside safety; and miscellaneous traffic control.
In addition to check-offs on the form, narrative comments are added to describe individual features observed. These include points of concern and areas that need improvement, as well as features or treatments viewed as positive.
Based on experience gained over the years, a number of specific points have been identified that are especially problematic, and each region was directed to develop a plan to ensure that these points, referred to as "emphasis points," are adequately addressed on a regional basis. The emphasis points listed are: sign condition; unneeded signs; no low-mounted signs; countdown signs; flagger signs; sign visibility; accommodation of pedestrian and bicycle traffic; merge taper lengths; flagging procedures; temporary concrete barriers; pavement bumps; and temporary sign supports.
These points are graded as "OK," "occasional problem" or "needs improvement."
The inspection consists of driving through the project in each direction, generally on each of the main approaches. In addition, one or more minor approaches, such as intersecting roadways or major driveways, also are examined. The inspection vehicle may stop from time to time to observe specific features in more detail. However, nearly all of the observations are completed from inside the vehicle. Depending on the nature and complexity of the project, multiple trips through the zone may be needed.
The objective is to obtain adequate information to characterize the project, while limiting time spent at each site so that a larger sample can be obtained.
Following completion of the inspection and entry of data and comments an overall quality rating is assigned.
The overall quality rating (a six-point scale) defines traffic control effectiveness at the time of inspection. The rating is based on team consensus following adequate discussion. Ratings are assigned as whole points, and when a significant difference cannot be resolved the majority rating is entered and the minority rating is noted for discussion at the debriefing.
The assigned rating represents a point sample of the project at the time of inspection. However, it is based on an assessment of how well the temporary traffic control serves all traffic conditions that can reasonably be expected. Also considered are anticipated performance of traffic control devices and traffic control schemes during adverse conditions such as darkness and rainfall.
Based on experience of the inspection team, and some inspections actually conducted under adverse conditions, combined with knowledge of the range of traffic conditions likely to occur on the project, it is reasonable to extend the inspection to assess the overall effectiveness of the traffic control. However, it’s also recognized that traffic control on individual projects varies from day to day. The quality rating assigned is thus a point sample that may or may not be representative of the project at other times. Because a large sample is obtained, and is generally selected without prior knowledge of project conditions, the overall sample is thought to be representative of statewide conditions.
Ratings also consider the complexity and difficulty of traffic control on the project. On large, complex projects some noncritical deficiencies can be encountered without lowering the rating as long as the overall effectiveness is not significantly affected. For example, a few signs or channelizing devices in less than optimum condition would not lower the rating on a large project. On small or simple projects, where only a few traffic control devices are needed, even a few relatively minor deficiencies have a greater relative effect, and thus may affect the overall rating.
Minor flaws or deterioration on individual devices, and minor technical flaws in devices or their application, usually have little effect on the overall rating, as long as they can be corrected by minor adjustments or fine-tuning. On the other hand, deficiencies that may induce a driver to make a serious error, or that increase the severity of a driver mistake or accident, have a pronounced effect on the rating.
Following each regional inspection is a debriefing and then three separate reports are prepared. The first provides an overall summary of the statewide inspection, including all construction, maintenance and permit work. This report, which summarizes quality ratings and provides a detailed overview of specific strengths and weaknesses, is submitted to the FHWA in fulfillment of requirments for the federal-aid highway program.
Two other reports are prepared for the construction and maintenance program areas. Quality ratings and emphasis point scores are tabulated program-wide, and results are compared to past years to permit tracking of program progress.
Rise in temp
Results have shown that the quality of temporary traffic control on construction projects, as measured by the quality rating system, increased markedly over the first few years the system was used—both in terms of average ratings and in fewer projects with very low scores. Over the past several years average ratings have stabilized around 4.3 to 4.4, and the percent of projects rated 4 or 5 has stabilized near 85%. Projects rated less than 3 make up only about 2% of the projects inspected.
Considering all emphasis points combined, average scores have improved from 70.9% "OK," with 13.3% "needs improvement," in 1992 to 76.5% "OK" and 7.5% "needs improvement" in 1999.
Over the past decade, NYSDOT has implemented widespread improvements in work-zone traffic control. These include enhanced specifications, implementation of new technology, new design procedures, MUTCD improvements and stricter compliance with existing requirements and basic principles. Several examples that were identified through or supported by the work-zone inspection program include:
Improved temporary traffic barriers
Temporary concrete barrier receives added attention to ensure that it meets warrants and that installations are properly designed to protect the hazard. Special emphasis is directed to protecting barrier ends.
Inspection results have supported the department change from signal flags to stop/slow paddles, and also have focused attention on improved flagging techniques, better setups for flagger stations and elimination of flagger warning signs when flaggers are not present.
Reduction of signing conflicts
An early concern identified by the inspections is the conflict caused by the close proximity of multiple temporary signs, warning drivers of different conditions in the same general area and in some cases providing conflicting information in terms of advisory speed or distance to the condition. Attention focused through several emphasis points, and discussed in the annual summary reports and other correspondence, has achieved substantial improvements for this concern.
Pedestrian and bicycle accommodations
Inspection results over several years indicated that pedestrians and bicyclists are not always adequately accommodated in work zones, placing them at greater risk than they would otherwise face or making it difficult for them to reach their destination. In 2000, a new emphasis point was added to address this issue, and the department is developing design and construction guidelines to ensure safe, convenient accommodations for pedestrians and bicyclists in all work zones.
Traffic control device condition guidelines
In cooperation with the American Traffic Safety Services Association, condition guidelines were developed for traffic control devices to guide project staff and contractors in determining when devices are in acceptable condition.
Interaction between main office and regional staff
A primary benefit of the inspection program has been increased interaction and communication between department staff in the main office, where standards and specifications are developed, and the regional office, which has the responsibility for project design and construction.