Terhaar, Edward F.

This presentation pertains to report 2014-44, Implementation of Automatic Flagger Assistance Devices (AFADs) for Minnesota Department of Transportation Flagger Operations.

Flagging operations are a critical part of construction and maintenance activities on our highways. Flagging personnel are trained to effectively and safely communicate the location of construction or maintenance activities to the traveling public. Due to the nature of the work; flagging personnel are located on the roadway near the work zone; which can result in dangerous vehicle and flagger interactions. With the increasing levels of distracted drivers; safety of flaggers and workers in work zones is an increasing concern. Unfortunately; flagging personnel deaths and near misses continue to occur on our highways during each construction season. Flagging operations can occur during both stationary and moving operations on two-lane; high-speed roadways. Stationary operations occur at a single location for a specific amount of time. The use and benefits of AFADs at stationary locations is documented in the report Implementation of Automatic Flagger Assistance Devices (AFADs) for Minnesota Department of Transportation (MnDOT) Flagger Operations. Moving operations involve work zones that are continuously moving; such as pavement crack sealing operations. The use of traditional AFADs in a moving operation is difficult due to the towing requirements of the devices. In order to capture the benefits of AFADs in a moving work zone; the stationary AFAD needed to be modified to allow for self-propelled motion to follow the moving operation.

This Sinusoidal Rumble Strip Design Optimization Study presents results of sound level monitoring of four types of centerline rumble strips installed along Trunk Highway (TH) 18 in Mille Lacs and Aitken counties in Minnesota. This study is in response to objections raised by some landowners about the unwanted noise caused by vehicles traveling over rumble strips when they drift over the edge or centerline of the roadway. By changing and modifying the design, the ultimate goal is to provide the maximum safety by capturing the drivers attention through in-vehicle generated sound levels while minimizing the associated external noise generated by the rumble strips. Tests on TH 18 were performed with three different vehicles passenger car, pickup truck and a class 35 tandem dump truck. A single speed of 60 mph was used, as this was shown to provide the most meaningful data in the previous study. For each of the designs, an initial test was performed with vehicles traveling on normal pavement, followed by three passes on the rumble strip. Rumble strip designs 1 and 4 created lower exterior sound level increases but created interior levels similar to designs 2 and 3. The external results correspond to the depth of the rumble strip design, with designs 1 and 4 having a maximum depth of 1/8 inch less than designs 2 and 3. The interior sound level increases are similar for all four designs but vary by vehicle type. All of the designs created increases greater than 10 dBA for the passenger car, which is a desirable level for gaining attention of the driver. For the pickup truck, the interior sound level increases ranged from 4.5 to 6.8 dBA, while the increases for the dump truck ranged from 0.8 to 2.7 dBA.

This Rumble Strip Noise Evaluation study presents results of sound level monitoring of three types of longitudinal rumble strips installed along the edge of two-lane rural roads in Polk County, Minnesota. The study is in response to objections raised by some landowners about the unwanted noise caused by vehicles traveling over rumble strips when they drift over the edge or centerline of the roadway. By changing and modifying the design, the ultimate goal is to provide the maximum safety by capturing the driver's attention through tactile and sound levels while minimizing the associated external noise generated by the rumble strips. Both exterior and vehicle interior sound levels were measured from three longitudinal edge of pavement rumble strip designs - California, Pennsylvania and Minnesota. Simultaneous digital audio files were also recorded. Three vehicles were used - a passenger car, pickup, and semi-trailer truck. Tests were performed at 30, 45 and 60 mph. Comparison of exterior and interior sound levels and audio shows that the Pennsylvania design is the quietest, both interior and exterior. The interior level of the Minnesota and California designs are similar but exterior levels are higher for the Minnesota design.

Flagging operations are a critical part of construction and maintenance activities on our highways. Flagging personnel are trained to effectively and safely communicate the location of construction or maintenance activities to the traveling public. Due to the nature of the work, flagging personnel are located on the roadway near the work zone, which can result in dangerous situations. With the increasing levels of distracted drivers, safety of flaggers and workers in work zones is an increasing concern. Unfortunately, flagging personnel deaths and near misses continue to occur on our highways during each construction season. Automated Flagger Assistance Devices (AFADs) are portable traffic control devices used by flagging personnel instead of traditional flagging equipment. The Minnesota Department of Transportation Research Services section purchased three sets of AFADs for district use. The objective of this research project was to explore the use of the equipment and demonstrate utility. Research shows that it is safer to pull flagger personnel out of traffic using these devices. However, based on conversations with MnDOT personnel, there has been resistance in the past using these devices on a regular basis.