Institute for Transportation

About the research

The Swarco Rumble device was compared directly with asphalt rumble strips (Kansas DOT standard) for effectiveness in garnering driver attention. Three measures of effectiveness were used: vehicle speed reduction, sound levels inside the vehicle, and vibration of the vehicle body. Additionally, sound levels at the roadside were examined. A cost comparison was performed based solely on installation and removal time plus life cycle costs. Safety benefits were not quantified. The Rumbler strips performed similarly to the asphalt strips with respect to sound and vibration inside the vehicle, and with respect to speed reduction. Sound levels at the roadside were higher for the Rumbler. For a single application, the Rumbler is approximately three times as expensive as asphalt strips (roughtly $1,500 per approach for the standard KDOT configuration), but if the Rumbler units are reused the costs are very similar. It was demonstrated that the rumbler could be reused without significant loss of performance. The rumblers proved to be very secure, remaining affixed to the pavement for six weeks with the only failures occurring when a couple of the strips were improperly installed (i.e., too little adhesive was used) and when something tore off pieces of the strips (likely farm equipment inappropriately dragging a metal blade). It was recommended that the strips be allowed on KDOT construction projects, and KDOT has since approved their use.

About the research

Although extensive research has been conducted on urban freeway capacity estimation methods, minimal research has been carried out for rural highway sections, especially sections within work zones. This study attempted to fill that void for rural highways in Kansas, by estimating capacity of rural highway work zones in Kansas. Six work zone locations were selected for data collection and further analysis. An average of six days’ worth of field data was collected, from mid-October 2013 to late November 2013, at each of these work zone sites. Two capacity estimation methods were utilized, including the Maximum Observed 15-minute Flow Rate Method and the Platooning Method divided into 15-minute intervals. The Maximum Observed 15-minute Flow Rate Method provided an average capacity of 1469 passenger cars per hour per lane (pcphpl) with a standard deviation of 141 pcphpl, while the Platooning Method provided a maximum average capacity of 1195 pcphpl and a standard deviation of 28 pcphpl. Based on observed data and analysis carried out in this study, the suggested maximum capacity can be considered as 1500 pcphpl when designing work zones for rural highways in Kansas. This proposed standard value of rural highway work zone capacity could be utilized by engineers and planners so that they can effectively mitigate congestion at or near work zones that would have otherwise occurred due to construction/maintenance.

About the research

Flagger-controlled work zones, by their very nature tend to utilize fewer traffic control measures than other work zones. Often these work zones are in place for only a short duration of time, so adding signing or positive protection beyond the minimum guidance directed by the MUTCD is rarely done. In these situations, the flagger is the key to effective traffic control, and so his/her visibility and conspicuity are critical to keeping motorists and workers safe. In an effort to increase flaggers’ visibility and conspicuity, several vendors have begun marketing STOP/SLOW paddles, personal protective equipment, and other ancillary devices equipped with various technologies – typically including embedded LED lighting. While a wide variety of studies have been undertaken to evaluate the technology-enhanced flagger devices, there has been little effort to examine these devices on the basis of perceived usefulness to field personnel and understanding by motorists. This study was aimed at obtaining responses from field personnel regarding the perceived usefulness and workability of these devices, while synthesizing the effects of these technology-enhanced devices based on flagger focus groups and driver survey responses.

The results of the focus groups revealed that weight of devices, conspicuity of flaggers, and awareness of drivers were among the influential criteria for field personnel to opt for a flashing STOP/SLOW paddle over a standard paddle. Interestingly, the standard 24″ STOP/SLOW paddle and the standard fluorescent yellow safety vest with orange striping emerged to be favorites among focus group participants over other technology-enhanced equipment displayed. Additionally, 72 percent of participants agreed that red and/or amber LED lighting attached to cones appeared to have the best potential for large visibility gains, versatility of applications, and ease of use. For the motorist surveys, only 28 percent of drivers indicated that they saw the STOP sign or flagger in work zones when enquired about the things that they observed. When asked about their opinions regarding the displayed STOP sign, 74 percent of in-favor drivers stated that it commanded their attention or fulfilled a need, whereas 86 percent of those not in-favor indicated that they either did not see it or thought it was hard to see. Also, more than half (54 percent) of the surveyed drivers did not think that the flashing STOP/SLOW paddles indicated a more important situation than if the paddle did not flash. Overall, only 26 percent of drivers stated that they drove differently because of the flashing STOP/SLOW paddles.

Vendor: University of Kansas

About the research

Safety in highway work zones has been a major concern for many decades. Over the years, government agencies and highway industry have developed work zone safety training programs to educate general public, professionals, and government employers. Existing training programs are conducted in the old fashion classroom setting which has some disadvantages such as high travel costs and locations far away from jobs. The objective of this research project was to develop a web-based training program for highway work zone safety. The developed program was built on advanced computer science technologies and delivered via Internet so that a trainee can access the training materials at any time and at any location as long as there is an Internet service. Training topics cover sign, marking, highway traffic signal, and temporary traffic control. At the end of training, a trainee will have an opportunity to take an on-line quiz with 50 questions. A certificate will be sent to the trainee via e-mail if that person’s test score is higher than the passing grade. The developed web-based training program has several advantages. First, using the developed program will eliminate the travel costs for the instructors and trainees. Second, both the instructors and trainees will spend less time away from their jobs. Third, the developed program can be easily modified and updated with any new information. Finally, trainees can learn the training materials at their own pace. The self pace format can be easily fitted in a busy working schedule.

Vendor: University of Kansas

About the research

Portable changeable message signs (PCMSs) have been employed in highway work zones as an innovative temporary traffic control (TTC) device in the United Stated for many years. The traditional message format on a PCMS is text-based, which has been found to have several limitations in recent studies, such as confusing drivers and delaying their responses during driving, being difficult to read for older drivers and non-English-speaking drivers, and having a short range of legibility. The use of graphic-aided messages on PCMSs has many advantages over text-based PCMSs based on a number of previous laboratory simulation experiments. This research project used field experiments and driver surveys to determine the effectiveness of a graphic-aided PCMS on reducing vehicle speed and drivers’ acceptance of utilizing a graphic-aided PCMS in the upstream of a one-lane two-way rural highway work zone. Field experiment were conducted to compare the effectiveness of text PCMS, graphic-aided PCMS, and graphic PCMS on reducing vehicle speed in a highway work zone in Kansas , and to develop regression models of the relationship between mean vehicle speed and distance under three PCMS conditions. Driver surveys were conducted to evaluate drivers’ opinions on the implementation of a graphicaided PCMS in the highway work zone. The findings showed that 1) using a text, a graphic-aided, and a graphic PCMS resulted in a mean vehicle speed reduction of 13%, 10%, and 17%, respectively; 2) using a graphic-aided PCMS reduced mean vehicle speed more effectively than using a text PCMS from 1,475 ft to 1,000 ft in the upstream of a work zone; using a graphic PCMS reduced mean vehicle speed more effectively than using a text PCMS from 1,475 ft in the upstream of the work zone to the location of the second TTC sign (W20-4 sign); 3) the majority of drivers understood the work zone and flagger graphics and believed the graphics drew their attention more to the work zone traffic conditions; and 4) more drivers preferred the information to be presented in the graphic-aided and graphic formats if the graphic-aided and graphic PCMSs were available.

About the research

The current report details efforts to determine if observers attend more closely to moving work zone signs if those signs are surrounded by a fluorescent yellow green border. The logic of this signage change is that there is insufficient color contrast between the warning signs and the vehicles on which they are mounted. Two laboratory studies were conducted using very sensitive and robust techniques to measure attention to signs with and without the FYG border. In each study, a different method for assessing attention was used. In the first study, a perceptual change detection method was used in which observers were required to detect a change to an object in a traffic scene. Changes to more frequently attended objects are noticed more rapidly. A comparison of change detection times for signs with and without the FYG border revealed no difference in the amount of attention allocated to the sign when the FYG border was added. In the second study, eye-tracking data was collected for a set of observers. An increase in fixation time on an object indicates more attention is being paid to that object. In this study, there was again no difference between the two sign types. We conclude there is no evidence that the addition of a FYG border increases driver attention to vehicle mounted warning signs.

Vendor: Iowa DOT

About the research

The Traffic Graphics Software is a comprehensive set of images for use in CorelDraw, including macros, which help produce professional diagrams easily and quickly. This evaluation examined the effectiveness of the software in creating traffic control diagrams. A full day of training was provided by the Professional Traffic Graphics. The software was evaluated by KDOT personnel from two departments: traffic engineering and public relations. Both areas found the software easy to use and capable of generating complex traffic control diagrams quickly and efficiently. The traffic engineering area felt that the software was powerful and easy-to-use, but not necessarily superior to the CAD-based software currently used for this purpose. The public relations personnel felt that this software would represent an improvement over their current methods of generating traffic control diagrams. One key difference between the two responses may be that the public affairs personnel had previous experience with CorelDraw, whereas the traffic engineering personnel did not. The public affairs personnel felt the software was a good investment and would recommend its purchase if the decision was theirs to make. In general, the Traffic Graphics Software is simple to use, although Corel Draw receives mixed reviews with respect to its learning curve.

Vendor: Professional Traffic Graphics