Evaluating the Safety Impacts of Flashing Yellow Permissive Left-Turn Indications in Massachusetts: Approach-Level Analysis

Given the novelty of the Flashing Yellow Arrow (FYA) in Massachusetts, this research study provides MassDOT with a greater understanding of their impacts from an approach-level perspective. More so, this study provides the agency with a holistic overview of infrastructure and operational impacts at each of these intersections, ultimately leading to an improved understanding of future design characteristics. Approach-level analyses remain the most appropriate method to assess the true impact of the permissive indication as well as infrastructure (e.g., turn lane length, LT lane offset, etc.) and operational (e.g., clearance intervals, phase sequence, etc.) elements. This study evaluated the before and after crashes at 200 statewide FYA intersections from an approach level to better understand the safety impacts of the LT permissive FYA signal. The advancement of these crash data analytics, methodologies, and applications will continue to remain important in years to come and will increase safety by providing an increased understanding of conflict risk at signalized intersections involving FYAs

The Role of Street Trees for Pedestrian Safety

92312This research report studies the link between street trees and the gap between pedestrians\u2019 perceptions of safety and their actual safety while walking along street corridors. Prior to this report, there was little research highlighting the relationship between street trees and pedestrian safety. The research team undertook two projects to understand the role of street trees and pedestrian safety: (1) An analysis of 181 pedestrian intercept surveys across streets with varying street tree cover; and (2) A GIS mapping analysis that measured urban design variables and street tree characteristics alongside recorded pedestrian-vehicle crashes. Overall, street trees did positively impact pedestrian safety, but the impact was small and further research is needed. These findings support the work of previous research and contain relevant information for street redesign standards and planning, especially Complete Streets guidance and technical assistance. Street trees can serve as an option for applying Complete Streets principles into smaller-scale projects to improve pedestrian mobility and community livability, especially in environmental justice areas. There may also be ways to leverage street tree advocacy and streetscape redevelopment projects through existing funding programs, and promote inter-agency collaboration and public-private partnerships

Measuring Left-Behinds on Subway

ISA# 92312Publication Date from Cover: May 2018The Massachusetts Bay Transportation Authority (MBTA) uses performance measures to monitor its service and measure improvement. This project supports the development of measures that track the customer experience instead of the performance of vehicles. Current measures are based on fare card records and assume that passengers are able to get on the first available vehicle that arrives at a stop or station. There is not currently a way to measure people left behind on subway platforms when vehicles are too full to board. This report presents the development of methods to measure or estimate the number of passengers that are left behind when vehicles are too crowded to board and the distribution of waiting times experienced by passengers, accounting for left-behind passengers. In addition to making use of existing vehicle location data, the study includes evaluation of two potential technologies for measuring passengers: automated passenger counting from surveillance video feeds, and tracking of Media Access Control (MAC) addresses from Bluetooth and Wi-Fi-enabled wireless devices. The occurrence of at least one passenger being left behind can be estimated with 90% accuracy, and the total number left-behind passengers during a rush period can be estimated within 10%. Challenges and opportunities for the future are identified

Construction and Materials Best Practices for Concrete Sidewalks: Phase II \u2013 Long-Term Performance and Hot-Weather Placement Effects

This report summarizes the investigation of construction practices and materials to develop durable concrete sidewalks which can resist scaling damage caused by exposure to freezing environment and deicer application. Over 16 months, a field study accompanied by laboratory testing was conducted to identify factors that affect the performance and durability of sidewalks. The variables considered for the study are concrete mix design, placement and finishing practices, curing methods, and deicer application. The placement of the sidewalks took place in late July 2021, to investigate the impact of hot weather concreting practices on the performance of sidewalks. Forty-eight sidewalk panels were placed behind Robert Brack Structural Engineering Laboratory at University of Massachusetts Amherst (UMass). During the sidewalk placement, cylinders and rectangular prisms were placed for laboratory testing. Thirty-two rectangular prisms were subjected to same curing method as the corresponding sidewalks for scaling resistance test in laboratory via BNQ NQ 2621-900. The results of this study indicate that mixture design formulation, curing method, de-icing method, and temperature based concreting practices impact the performance of scaling in concrete sidewalks. Recommendations incorporating these variables are presented in this report with accompanying testing standards and procedures

Massachusetts Depth to Bedrock Project

The depth to bedrock is perhaps one of the most important surfaces that is fundamental to many practical engineering and geological problems. Yet it is not well understood everywhere. Knowing the depth to bedrock for transportation projects not only influences cost but may also affect selection of the appropriate foundation system for a particular structure. Furthermore, estimates of the bedrock depth, along with the type of overburden (e.g., glacial till, varved clay, sand and gravel) help determine the most appropriate subsurface investigation method to use during project planning, and reduces construction delays and claims brought forward by contractors. Accordingly, there is some level of uncertainty in planning subsurface investigations for any transportation project when depth to bedrock information is lacking. This project is an attempt to reduce the uncertainty in highway project planning by providing interpolated statewide data layers of the depth to bedrock and bedrock altitude at 100-meter resolution based on currently available subsurface data. In addition, maps depicting the level of confidence in the estimate of the bedrock altitude and depth are also provided. The confidence is based on both the interpolated prediction standard error as well as the measurement uncertainties associated with the input data

Change in Mental Models of ADAS in Relation to Quantity and Quality of Exposure

69A3551747131Given the importance of mental models towards safe interaction with Advanced Driver Assistance Systems (ADAS) and the various human factors challenges regarding ADAS such as miscalibrated trust and the effect on workload, it is important to understand how different types of driving experiences and exposures affect drivers\u2019 mental models about ADAS. The objective of this study was to examine how the frequency and quality of exposure (exposure defined as driving through events or situations that have some bearing on the functions of the Adaptive Cruise Control (ACC)) affect drivers\u2019 mental models about ACC, their trust, workload, and their use of the systems as measured by their behaviors around disengaging ACC

Bulletin.

Issued by the University under varying forms of its name.Some volumes incorporate 2-date school years.Includes: Summer session bulletin; Undergraduate course and faculty directory; University of Massachusetts at Boston bulletin; Parents newsletter; Graduate school bulletin; Medical school catalogue; General information; and other miscellaneous publications.Some vols. include Reports (which are issued as Public document no. 31, pt. 1 of Massachusetts); Catalog (which is issued as Public document no. 31, pt. 2 of Massachusetts)Mode of access: Internet.Complete set of Bulletins in University Archives

Fruit notes.

v.48-49 (1983-1984