Accident Analysis of Ice Control Operations

Highway maintenance involves all work necessary to assure that the highway system is kept safe, open to traffic, and in proper working order. During winter, the removal of snow and ice from streets, roads, and highways is a major maintenance operation. With more than 135 million motor vehicles registered in the United States and roughly four million miles of roads and streets, local governments must be prepared to deal with the removal of snow and ice to insure public safety, and to reduce the adverse impact on the affected area’s economy. Snow and ice covered roads can paralyze the functioning of the community and pose a considerable threat to the public safety. They produce hazardous driving conditions which increase traffic deaths, injuries, and property damage. The general assumption has always been that snow and ice on highways causes accidents. There are a number of reasons for this assumption. Snow and ice reduce the coefficient of friction between the pavement and vehicle tires, making maneuvering of the vehicle very difficult and occasionally impossible. Ice is not always apparent to the motorist and is not uniform, so that the driver is not always prepared when he encounters an icy section on the roadway. Vehicle mobility is reduced, causing possible severe disruption of important public emergency services, such as fire, police, and ambulance operations. Without close attention to the effective removal of snow and ice from roads, the economy of the region involved will suffer, and traffic accidents will escalate. Most activities of individuals, industries, utilities, schools, and government activities are handicapped in social and economic ways during the duration of snow and ice conditions on roads and streets

Public Perceptions of the Midwest’s Pavements: Policies and Tradeoffs in Pavement Improvement

With the budget crisis plaguing so many states, pavement management will compete more vigorously for limited funds. Findings reported from a tri-state pooled-fund research project provide insights and guidelines for pavement improvement derived from the perceptions of the driving public. The Phase II responses from statewide surveys in Iowa, Minnesota, and Wisconsin address the topics of perceptions of the State Departments of Transportation (DOTs), pavement repair tradeoffs, and pavement evaluation. The results disclose specific public perceptions of priorities for spending limited highway funds. Implications for pavement management, policy, planning, as well as for marketing to garner additional funds are explored

Public Perceptions of the Midwest\u27s Pavements: Explaining the Relationship Between Pavement Quality and Driver Satisfaction

A three-phase study involving focus groups and sample surveys was conducted in three Midwestern states to assess the amount of satisfaction that motorists who drive on rural, two-lane state highways have with the pavement characteristics of those highways and to explain the relationship between the actual physical condition of the pavements and motorists\u27 satisfaction. Consistently in each state, the direct relationship between pavement quality and driver satisfaction was mediated by cognitive structure—a set of five specific beliefs motorists have about the pavement. The part of the study that (a) applies a powerful psychological model to the task of understanding motorists\u27 satisfaction with pavements; (b) offers reliable measures of driver satisfaction with pavement quality and of belief-based cognitive structure related to pavements; (c) has accomplished the important task of identifying the most salient pavement features considered by members of the public when they evaluate pavement quality; and (d) illustrates very clearly the importance of considering motorists\u27 beliefs about the pavement, issues of trust, and aspects of the Fishbein\u27s attitude model and Ajzen\u27s theory of planned behavior when trying to predict or understand driver satisfaction are covered. Although the pavement management indices used by the state departments of transportation will continue to be used to establish thresholds for improvement triggers, these indices alone do not explain such broad concepts as satisfaction with a particular pavement

Public Perceptions of the Midwest’s Pavements - Introduction

The “Public Perceptions of the Midwest’s Pavements” is the largest survey of public perceptions of satisfaction and improvement policies on rural, two-lane highways ever conducted in the 20th Century in the USA. The project was a Pooled Fund effort undertaken by the Wisconsin DOT and included equal participation of the Iowa and Minnesota DOTs. Approximately 4500 drivers and over 1000 highway segments were surveyed in the three states in all three phases of the project, between 1996 and 2000. The surveys included improvement policy and construction alternative issues and trade-offs, as well as surveys of beliefs and attitudes of the public that affect public trust and satisfaction. The results of the project are reported in phase reports (pdf), with a report on each phase in each state

Accident Analysis of Ice Control Operations - Abstract

This widely publicized study by Marquette University was the first of its kind in North America to document, with statistical validity, the direct benefits of deicing operations. It was patterned after a German study of the Technical University at Darmstadt during the late 1980s. The Marquette study was conducted during the winter of 1990-1991 in four states: New York, Illinois, Minnesota and Wisconsin. It covered a network of 520 miles of randomly selected twolane undivided highways and 50 miles of multi-lane divided freeways in the four states. The sections included were primarily rural or sub-urban. Data collection included estimated hourly traffic volumes, accidents, and operating parameters including the time and amount of de- icer used for equal 12 hour periods before and after “zero” hour (the hour of the actual spreading of deicer). The direct costs of the operation were also collected and calculated. Estimates of traffic volume reduction due to snow, travel time reduction and the costs associated with the above items were made using standard methodology. Data on winter events were obtained from event logs of the organizations and meteorological data available about the storms. The data collection included over 125 test sections in the four states and a total of 226 events, with almost 4600 sub-events (a single event on a single test section). For two-lane highway sections, the rate for all accidents was about eight times higher in the four hours before than it was in the four hours after “zero” hour (hours with the most significant difference). The rate for injury accidents was nine times higher before than after and for property damage only 7 times higher. There was an 88 percent reduction in accident costs in the four hour after period. The ratio of direct benefits to direct costs was about 6.5 to 1. The average direct costs were paid for after the first 71 vehicles used the highway, or paid for in about the first 25 minutes aft er the “zero” hour. For freeways, the rate for all accidents was about 4.5 times higher in the two hours before (hours with the most significant difference) than after “zero” hour. The rate for injury accidents was seven times higher before than after, and the rate for property damage accidents was two times higher before than after. There was an 88 percent reduction in accident costs in the two hour after period. The ratio of direct benefits to direct costs was about 3.5 to 1. The average direct costs were paid for after the first 280 vehicles used the highway, or paid for in about the first 35 minutes after “zero” hour. The study suggests this type of methodology for state-of-the-art cost benefit studies in the future. It is based on a doctoral dissertation completed at the University

Public Perceptions of the Midwest’s Pavements: Policies and Thresholds

A 5-year, pooled fund study with the Iowa, Minnesota, and Wisconsin departments of transportation assessed the public\u27s perceptions of pavement improvement strategies and developed thresholds of satisfaction using the departments\u27 physical indices, such as pavement ride and condition on rural, two-lane highways in the states. Approximately 3,600 drivers in the three states were involved in the three phases of the project, which included 18 focus groups, 400 statewide surveys in each state, and 2,300 targeted surveys across the three states. A multidisciplinary team from Marquette University and a mass media survey lab conducted the studies. A summary of focus group methods and purposes and a three-state summary of policy and improvement issues are provided. More than 450 highway segments were surveyed in Phase III, with input from 2,300 drivers through a two-step recruitment and postdrive interview. Thresholds of International Roughness Index and condition indices are summarized for the three states. The study found a high degree of trust in the three departments of transportation and public support for building longer-lasting pavements and minimizing delay. A three-step methodology is recommended for other state studies. Physical data thresholds using both public satisfaction and the agreement to improve are presented for each state\u27s physical pavement indices (ride and condition)

Public Perceptions of Wisconsin’s Pavements and Tradeoffs in Pavement Improvement

Findings are reported from Phase II of a three-phase pooled-fund project in Wisconsin, Iowa, and Minnesota to determine perceptions of drivers regarding pavement of rural two-lane highways. Among the survey topics were drivers\u27 trust in the state department of transportation (DOT), pavement improvement trade-offs, and pavement evaluation. Results of the Wisconsin portion of the survey data are the focus of this study. The survey questionnaire was based in part on Phase I focus groups conducted to gauge beliefs about pavements as well as the language describing ruts, tining, and other pavement characteristics. Phase II entailed a statewide telephone survey of at least 400 randomly selected drivers in each of the three states. Although the focus here is on Wisconsin results, survey responses across the three states were very consistent. Included in the findings discussed are perceptions of pavement and the state DOT and pavement improvement options relating to construction, travel time, and delays. Results disclose key public perceptions of priorities with regard to spending limited funds. Also discussed are statistically significant relationships providing additional insights into public perceptions and pavement improvement on rural two-lane highways

Public Perceptions of the Midwest’s Pavements - Wisconsin - Executive Summary

This report summarizes Wisconsin results of a five year, Pooled Fund study involving the Wisconsin, Iowa, and Minnesota DOTs designed to 1) assess the public\u27s perceptions of the departments’ pavement improvement strategies and 2) to develop customer-based thresholds of satisfaction with pavements on rural two lane highways in each state as related to the Departments’ physical indices, such as pavement ride and condition. The primary objective was to seek systematic customer input to improve the Departments’ pavement improvement policies by 1) determining how drivers perceive the departments’ pavements in terms of comfort and convenience but also in terms of other tradeoffs departments had not previously considered, 2) determining relationships between perceptions and measured pavement condition thresholds (including a general level of tolerance of winter ride conditions in two of the states, including Wisconsin), and 3) identifying important attributes and issues that may not have been considered in the past. Secondary objectives were 1) to provide a tool for systematic customer input in the future and 2) provide information which can help structure public information programs. A University of Wisconsin-Extension survey lab conducted the surveys under the direction of a multi-disciplinary team from Marquette University. Approximately 4500 drivers in the three states participated in the three phases of the project. Researchers conducted six focus groups in each state, approximately 400 statewide telephone interviews in each state and 700-800 targeted telephone interviews in each state. Approximately 400 winter ride interviews were conducted in Wisconsin and Minnesota. A summary of the method for each survey is included. In Phase I, focus groups were conducted with drivers to get an initial indication of what the driving public believes in regards to pavements and to frame issues for inclusion in the more representative state-wide surveys of drivers conducted in Phase II of the project. Phase II interviews gathered information about improvement policy trade-off issues and about preliminary thresholds of improvement in terms of physical pavement indices. In Phase III, a two step recruitment and post-drive interview procedure yielded thresholds of ride and condition index summarized for each state. Results show that, in general, the driving public is tolerant of a poorer ride in Winter and they understand the cause. The driving public wants longer lasting pavements and are willing to pay for them. They want to minimize construction delay, improve entire sections of highway at one time but they dislike detours, and prefer construction under traffic even if it stretches out construction time. Satisfaction with pavements does not correlate directly to a high degree with physical pavement indices, but was found instead to be a complex, multi-faceted phenomenon. A psychological model (after Fishbein/Ajzen) was applied to explain satisfaction to a respectable degree (R2 of .7) for the social sciences. Results also indicate a high degree of trust in the three DOTs which is enhanced when the public is asked for input on specific highway segments. Conclusions and recommendations include a three-step methodology for other state studies. Physical data thresholds based on both public satisfaction and the agreement to improve are presented for each state’s physical pavement indices (ride and condition). Recommended changes to the quality ranges of the physical indices where appropriate are also made

Public Perceptions of the Midwest’s Pavements - Minnesota - Executive Summary

This report summarizes Minnesota results of a five year, Pooled Fund study involving the Wisconsin, Iowa, and Minnesota DOTs designed to 1) assess the public\u27s perceptions of the departments’ pavement improvement strategies and 2) to develop customer-based thresholds of satisfaction with pavements on rural two lane highways in each state as related to the Departments’ physical indices, such as pavement ride and condition. The primary objective was to seek systematic customer input to improve the Departments’ pavement improvement policies by 1) determining how drivers perceive the departments’ pavements in terms of comfort and convenience but also in terms of other tradeoffs departments had not previously considered, 2) determining relationships between perceptions and measured pavement condition thresholds (including a general level of tolerance of winter ride conditions in two of the states), and 3) identifying important attributes and issues that may not have been considered in the past. Secondary objectives were 1) to provide a tool for systematic customer input in the future and 2) provide information which can help structure public information programs. A University of Wisconsin-Extension survey lab conducted the surveys under the direction of a multi-disciplinary team from Marquette University. Approximately 4500 drivers in the three states participated in the three phases of the project. Researchers conducted six focus groups in each state, approximately 400 statewide telephone interviews in each state and 700-800 targeted telephone interviews in each state. Approximately 400 winter ride interviews were conducted in Wisconsin and Minnesota. A summary of the method for each survey is included. In Phase I, focus groups were conducted with drivers to get an initial indication of what the driving public believes in regards to pavements and to frame issues for inclusion in the more representative state-wide surveys of drivers conducted in Phase II of the project. Phase II interviews gathered information about improvement policy trade-off issues and about preliminary thresholds of improvement in terms of physical pavement indices. In Phase III, a two-step recruitment and post-drive interview procedure yielded thresholds of ride and condition index summarized for each state. Results show that, in general, the driving public wants longer lasting pavements and are willing to pay for them. They want to minimize construction delay, improve entire sections of highway at one time but they dislike detours, and prefer construction under traffic even if it stretches out construction time. Satisfaction with pavements does not correlate directly to a high degree with physical pavement indices, but was found instead to be a complex, multi-faceted phenomenon. A psychological model (after Fishbein/Ajzen) was applied to explain satisfaction to a respectable degree (R2 of .67) for the social sciences. Results also indicate a high degree of trust in the three DOTs which is enhanced when the public is asked for input on specific highway segments. Conclusions and recommendations include a three-step methodology for other state studies. Physical data thresholds based on both public satisfaction and the agreement to improve are presented for each state\u27s physical pavement indices (ride and condition). Recommendations for changes to the quality ranges of the physical indices where appropriate are also made

Public Perceptions of the Midwest’s Pavements - Iowa - Phase III

There are several objectives to this report. The first objective is to describe the sample with regard to the physical pavement data and three measures of driver satisfaction. In this section, the proportion of respondents who are satisfied with pavements on two-lane, rural, state highways will be examined and the distribution of pavement condition and roughness indices will be presented. The second objective will be a short description of the highway segments and any differences in satisfaction found between regions and pavement types. This was done in Phase II in each state and a letter sent showing the results in all three states. That letter sets forth the revised work plan and budget for Phase III of the project. The third objective is to describe the relationship between physical pavement characteristics and driver satisfaction. This will include a description of both the magnitude of relationship as well as identifying critical International Road Index (IRI) and Pavement Condition Index (PCI) cutoffs where a majority of the sample were satisfied. This will be done for comparative purposes with the Phase II approach, using the total sample to compute cumulative percentages responding to each of the three series of satisfaction questions