Median Design and Accident Histories

The purpose of this study was to provide information concerning the accident histories of various median types to verify minimum requirements for width and cross section. Previous accident studies failed to disclose significant relationships between median width and accident rates. Those studies did not recognize or control several important variables that were controlled in the present study. The efforts here are to compare median types on rural, four-lane, fully controlled access facilities with similar geometries other than median types. An attempt was made to account for some of the Variability in the accident data. Thus, this study gives information on the operational performances of several medians and offers persuading analyses with respect to the design or styling of medians

Accidents at Median Crossovers

Safety improvements are often controversial subjects, especially when the subject is highways. Judgments must be made weighing lives and injuries against the hard realities of financing the construction and maintenance of highway systems. Median crossovers on rural and urban freeways and expressways are controversial design features. State police and maintenance forces claim that median crossovers are necessary and essential for their work and that more frequent location of crossovers is desirable. Engineers involved with highway safety maintain that crossovers create accidents, are not necessary, and should be eliminated. When working on an accident study evaluating median type, it became obvious that at times median crossovers were causing frequent accidents, especially in some locations and certain situations. Crossovers are locations on controlled access roadways where emergency and maintenance vehicles can cross the median to change their direction of travel. However, the motoring public also finds crossovers convenient for their use, even though the maneuver is illegal. This creates an accident producing situation. Accidents at median crossovers involving U-turning vehicles accounted for up to 25 percent of the total accidents on several road sections during some years investigated in this study. For a four year period involving the majority of toll roads and interstate roads in Kentucky, an average of five percent of all accidents were caused by vehicles using median crossovers. The purpose of this study was to analyze existing crossover locations, usage, and accidents so as to develop criteria on the necessity for and the location of median crossovers. Primarily, three sources of information were used. An inventory of existing crossover locations was obtained to determine the prevailing philosophy, if any, on crossover locations. Secondly, a comprehensive analysis of U-turn accidents at median crossovers was performed. The accident analysis included special study of roads where U-turn accidents were most prevalent. To evaluate crossover usage, interviews were conducted with district highway engineers and questionnaires were given to all state police who patrol interstate or toll roads in Kentucky. The questionnaire also provided an opportunity for the state police to express their opinions concerning the location and necessity for crossovers

Experimental Guardrail Installation

This is the final report on a limited investigation comparing the performance of painted steel, galvanized steel and aluminum guardrails. A previous report was issued in 1964. The final inspection of the project was made in November 1969. The project consisted of approximately 2500 lineal feet of each type of guardrail (see Figure 1 and Table 1). The painted steel and galvanized steel were installed in November 1962. The aluminum guardrails were installed in February 1963. All rails are the deep-beam type and were installed in accordance with special provisions which covered material requirements and erection procedures. The special provisions were included in the first report

Grooving Pavement Centerlines for Lane Demarcation

Lane demarcation is conventionally accomplished by use of white traffic paint placed as a skip line. Most traffic paints are beaded by premixing glass beads in the paint, by drop-on applications, or a combination of the two. The retrodirective properties of the beads greatly enhance nighttime visibility during dry weather; however, visibility of the lines is practically nil during wet nighttime driving. Submerged beads cannot redirect the light when the need for guidance is mosL critical. Thermoplastic striping materials have been used to varying degrees of success by numerous agencies. Wet nighttime visibility of thermoplastics, as experienced in Kentucky, is generally far superior to that of conventional beaded paints. Thermoplastics are placed at a thickness of 125 mils and are thereby less likely to become submerged than conventional paints, which are placed at film thicknesses in the order of 14 mils and dry to approzimately 8 mils. Late in 1965, the California Division of Highways reportedly issued a policy requiring the use of raised pavement markers as a replacement for most painted lines on future freeways and conventional highways. Other agencies have employed raised markers in various forms and have reported excellent to good wet nighttime visibility for markers remaining in place. Major disadvantages of the thermoplastics and raised markers are: they are quite expensive as compared to paint, they break or crack under traffic, and the present loss is high as a result of traffic and snow removal equipment. In addition, the raised markers are rather difficult to install. Christensen Diamond Services, Inc. of Salt Lake City, Utah, reportedly introduced the concept of grooving centerlines in an attempt to provide a rumble effect for alerting drivers straying outside their traffic lanes. It was later observed that the painted grooves were more visible at night during wet weather than were normal paint stripes. The concept of grooving and painting centerlines was thus promoted, and, as a result, several test sections were placed on Nebraska highways in the summer of 1968. In order to evaluate the effectiveness of grooving the centerline prior to striping, a section uf newly constructed pavement of I 71 in Carroll County, Kentucky, was chosen for an experimental installation. This interim report covers installation of the grooves and a preliminary evaluation of their value to date

Elements of Median Design in Relation to Accident Occurrence

The purpose of this study was to compare the accident histories of different median types and to provide verification of generally recommended median widths and slopes. A major limitation of the analyses was the small number of possible combinations of median width and cross slope available for study. The analyses reported provided evidence from accident histories to support the general requirement that wider medians are safer medians. It was indicated that medians should be a minimum of 30-40 feet wide for high speed facilities and that flat slopes should be provided; 4:1 slopes are inadequate for medians less than 60 feet wide. There was an indication that 6:1 or flatter slopes should be used. Raised medians provided an unsuitable vehicle recovery area on rural highways and were also undesirable from the standpoint of roadway surface drainage. The irregular interstate medians which result from independent roadway alignment should be used only with adequate clear zones in the median. Twelve-foot shoulders should be provided where guardrail is to be used

A Preliminary Evaluation of Mounds to Divert Wayward Vehicles Away from Rigid Obstructions

In the summer of 1965, the first fatality report involving an interstate median bridge pier in Kentucky caused concern among state and national officials for the safety of motorists who perchance or otherwise enter upon a collision course toward an unprotected bridge pier. A consensus of opinion seemed to indicate that some form of attenuation or deflection device was necessary. Early innovations employed various short guardrail configurations to deflect wayward vehicles from the piers. The use of small, short sections has since evolved until present methods include surrounding the bridge pier with several hundred feet of guardrail, including ramped-end treatment (see Figure 1). The use of guardrail has not been questioned from the standpoint of safety design, yet some effort has been applied by Kentucky and other states to finding an alternative approach. From these efforts, the use of mounds to decelerate and deflect vehicles originated. It was thought that this design concept was consistent with current safety developments as well as being an economical treatment of the problem, since most of the work involved in constructing the mound can be done during grade and drain construction using natural materials available on location. These mounds have since been constructed on certain interstate projects and on all bridge locations of the Jackson Purchase (51.4 miles) and Pennyrile (56.6 miles) Parkways in Kentucky. Having found no records of accidents involving these mounds in the interim, there has been no substantial means of evaluating the effectiveness of this innovation in preventing or reducing the severity of collisions with bridge piers. Consequently, it was decided that low speed excursions over a mound might provide a basis for evaluation. The Division of Research made a series of driver-controlled traverses at low speeds on a typical site constructed on a 60-foot median. The purpose of this report is to summarize the results obtained from these initial, low-speed tests and, in so doing, attempt to make some determination of the reliability of this particular type of earthwork. It is anticipated that these low-speed tests will be supplemented eventually by testing at higher speeds, using some form of remote guidance system in place of the human driver. Also, it must be emphasized that conclusions drawn from this report apply only to low-speed encroachments. Additional effects which may be encountered during high-speed testing can only be hypothesized at this time

Nerves and classifying spaces for bicategories

This paper explores the relationship amongst the various simplicial and pseudo-simplicial objects characteristically associated to any bicategory C. It proves the fact that the geometric realizations of all of these possible candidate `nerves of C' are homotopy equivalent. Any one of these realizations could therefore be taken as the classifying space BC of the bicategory. Its other major result proves a direct extension of Thomason's `Homotopy Colimit Theorem' to bicategories: When the homotopy colimit construction is carried out on a diagram of spaces obtained by applying the classifying space functor to a diagram of bicategories, the resulting space has the homotopy type of a certain bicategory, called the `Grothendieck construction on the diagram'. Our results provide coherence for all reasonable extensions to bicategories of Quillen's definition of the `classifying space' of a category as the geometric realization of the category's Grothendieck nerve, and they are applied to monoidal (tensor) categories through the elemental `delooping' construction.Comment: 42 page

Energy Reallocation to Breeding Performance through Improved Nest Building in Laboratory Mice.

Mice are housed at temperatures (20-26°C) that increase their basal metabolic rates and impose high energy demands to maintain core temperatures. Therefore, energy must be reallocated from other biological processes to increase heat production to offset heat loss. Supplying laboratory mice with nesting material may provide sufficient insulation to reduce heat loss and improve both feed conversion and breeding performance. Naïve C57BL/6, BALB/c, and CD-1breeding pairs were provided with bedding alone, or bedding supplemented with either 8g of Enviro-Dri, 8g of Nestlets, for 6 months. Mice provided with either nesting material built more dome-like nests than controls. Nesting material improved feed efficiency per pup weaned as well as pup weaning weight. The breeding index (pups weaned/dam/week) was higher when either nesting material was provided. Thus, the sparing of energy for thermoregulation of mice given additional nesting material may have been responsible for the improved breeding and growth of offspring

RSPCA and the criminology of social control

This paper contributes to a rethinking of animal abuse control and animal welfare protection in criminology, specifically, and in the social sciences more broadly. We do this, first, through a broad mapping of the institutional control complex around animal abuse in contemporary Britain. Second, we focus on the institutional strategies and practices, past and present, of the main agency of animal protection, and the policing thereof, in this society, namely the Royal Society for the Prevention of Cruelty to Animals (RSPCA). In looking back to this charity’s growth since the first decades of the nineteenth century at the time of the birth of modern industrial capitalism and also to its current rationale and practices as a late-modern, corporate organisation, we explore the seeming paradox of a private body taking a lead on the regulation and prosecution of illegalities associated with animal-human relationships. Finally, the ideology and strategy of the RSPCA are explored in the context of the often visceral and culturally influential ‘morality war’ associated with proponents, respectively, of animal rights (‘abolition’) and ‘anthropic’ welfare proponents (‘regulation’ and ‘protection’)