Accidents on Rural Interstate and Parkway Roads and Their Relation to Pavement Friction

Friction measurements were made with a skid trailer at 70 mph on 820 miles of rural, four-lane, controlled-access routes on the interstate and parkway systems in Kentucky. These facilities were subdivided into test sections and half-mile sites. Accident experience, friction measurements and traffic volumes were obtained for each subdivision. The expression of accident occurrence which correlated best with skid resistance was wet-surface accidents per 100 million vehicle miles. There was a definite trend exhibiting a rapid decrease of accidents with increasing Skid Number (70 mph) to 26 ± 1; thereafter, with increasing Skid Numbers, the rate of decrease was considerably lessened. This trend was developed using test-section data and verified using half-mile sites. Analysis of Peak Slip Numbers and accident occurrences indicated similar trends to those developed with Skid Numbers

Skid Resistance of Pavements [Sept. 1972]

Standard pavement types and experimental surfaces on roads throughout Kentucky were evaluated in terms of skid resistance and effects of traffic, wear, and polishing. Friction-vs-speed gradients and the relationships between locked-wheel and incipient friction were determined. Asphaltic concrete pavements on high-speed, four-lane roads were found to be significantly more skid resistant than on two-lane highways and somewhat more skid resistant than concrete surfaces (especially those containing calcareous gravel aggregates). Sand-asphalt surfaces containing significant proportions of limestone sands showed inadequate level of friction for the traffic sustained. Several experimental sand asphalts without limestone sands exhibited greater skid resistance; Kentucky rock asphalt surfaces remain the most skid resistant of all surfaces investigated

Skid-Test Trailer: Description, Evaluation and Adaptation

A two-wheeled skid-test trailer and towing vehicle were acquired in 1969. The trailer was designed primarily for measurement of steady-state friction at and above normal traffic speeds. Measurement of instantaneous wheel loads also permitted determination of peak or incipient friction. Factors and variables associated with the testing device and calibration and test procedures were investigated and standardized, and the trailer was adopted for routine testing. Comparative tests with the trailers of General Motors, Ohio, and West Virginia were conducted, and the data were correlated. The interim standard method of test using an automobile was correlated with the trailer to permit conversion of data accumulated in preceding years

Accidents on Rural Interstate and Parkway Roads and Their Relation to Pavement Friction

Friction measurements were made with a skid trailer at 70 mph (31 m/s) on 770 miles (1240 km) of rural, four-lane, controlled-access routes on the interstate and parkway systems in Kentucky. Each construction project was treated as a test section. Accident experience, friction measurements, and traffic volumes were obtained for each. Various relationships between wet-weather accidents and skid resistance were analyzed. The expression of accident occurrence which correlated best with skid and slip resistance was wet-weather accidents per 100 million vehicle miles. Accidents increased greatly as Skid Numbers (70 mph or 31 m/s) decreased from 27 ± 1. Analysis of Peak Slip Numbers and accident occurrences indicated similar trends

Skid Resistance of Pavements [July 1972]

Standard pavement types and experimental surfaces on roads throughout Kentucky were evaluated in terms of skid resistance and effects of traffic, wear, and polishing. Friction-vs-speed gradients and the relationships between locked-wheel and incipient friction were determined. Class I bituminous pavements on high-speed, four-lane roads were found to be significantly more skid resistant than on two-lane highways and somewhat more skid resistant than concrete surfaces (especially those containing calcareous gravel aggregates). Sand-asphalt surfaces containing significant proportions of limestone sands showed inadequate level of friction for the traffic sustained. Several experimental sand asphalts without limestone sands exhibited greater skid resistance; Kentucky rock asphalt surfaces remain the most skid resistant of all surfaces investigated

Accidents on Rural Interstate and Parkway Roads and their Relation to Pavement Friction

Friction measurements were made with a skid trailer at 70 mph (31 m/s) on 770 miles (1240 km) of rural, four-lane, controlled-access routes on the interstate and parkway systems in Kentucky. Each construction project was treated as a test section. Accident experience, friction measurements, and traffic volumes were obtained for each. Various relationships between wet-weather accidents and skid resistance were analyzed. Averaging methods were used as a means of developing trends and minimizing scatter. A moving average for progressively-ordered sets of five test sections yielded more definite results. The expression of accident occurrence which correlated best with skid and slip resistance was wet-weather accidents per 100 million vehicle miles (161 million vehicle kilometers). Accidents increased greatly as Skid Numbers (70 mph or 31 m/s) decreased from 27. Analysis of Peak Slip Numbers and accident occurrences indicated similar trends

Iron Behaving Badly: Inappropriate Iron Chelation as a Major Contributor to the Aetiology of Vascular and Other Progressive Inflammatory and Degenerative Diseases

The production of peroxide and superoxide is an inevitable consequence of aerobic metabolism, and while these particular "reactive oxygen species" (ROSs) can exhibit a number of biological effects, they are not of themselves excessively reactive and thus they are not especially damaging at physiological concentrations. However, their reactions with poorly liganded iron species can lead to the catalytic production of the very reactive and dangerous hydroxyl radical, which is exceptionally damaging, and a major cause of chronic inflammation. We review the considerable and wide-ranging evidence for the involvement of this combination of (su)peroxide and poorly liganded iron in a large number of physiological and indeed pathological processes and inflammatory disorders, especially those involving the progressive degradation of cellular and organismal performance. These diseases share a great many similarities and thus might be considered to have a common cause (i.e. iron-catalysed free radical and especially hydroxyl radical generation). The studies reviewed include those focused on a series of cardiovascular, metabolic and neurological diseases, where iron can be found at the sites of plaques and lesions, as well as studies showing the significance of iron to aging and longevity. The effective chelation of iron by natural or synthetic ligands is thus of major physiological (and potentially therapeutic) importance. As systems properties, we need to recognise that physiological observables have multiple molecular causes, and studying them in isolation leads to inconsistent patterns of apparent causality when it is the simultaneous combination of multiple factors that is responsible. This explains, for instance, the decidedly mixed effects of antioxidants that have been observed, etc...Comment: 159 pages, including 9 Figs and 2184 reference