The safety benefit of stop sign treatments at passive highway–rail crossings has been a subject of research for many years. The objective of this study is to assess the effectiveness of the stop sign treatment on crossing safety. Using the FRA database, the research focused on 26 years of vehicle–train accident history in the United States from 1980 through 2005. A before-and-after and cross-sectional statistical analysis was conducted for 7,394 public highway–railroad grade crossings that were upgraded from being controlled only by crossbucks to stop signs, without other traffic control devices or automatic countermeasures. The study found that accident rates based on annual accident frequency per 1,000 crossings were significantly higher during the period when crossings were controlled only by crossbucks than when they were controlled by stop signs. Further, this study developed negative binomial accident prediction models for paved and unpaved highway–rail grade crossings that included the effect of stop sign treatment. Taking account of specific attributes of crossings controlled only by crossbucks, decision makers and traffic engineers can use the models to examine the accident risks at crossings and assess the potential effectiveness of stop sign treatment.
A speed limit of 55 mph (88 km/h) is typically used on rural highways in the U.S. For locations where curbs are installed along these roadways, some transportation agencies have suggested the use of a reduced 45 mph (72 km/h) speed limit because, according to AASHTO, running into curbs at high speeds may cause significant vehicular damage and even severe injuries. However, it has also been argued that lowering the speed limit after the installation of curbs may cause confusion in drivers, who do not perceive the risk associated with the newly installed curbs and tend to operate their vehicles at the same, higher, speed as before. To better understand driver behavior on rural highways before and after curb installation and with different speed limits, researchers at the University of Tennessee conducted a series of experiments in two-lane and four-lane highways respectively on a high fidelity driving simulator. This paper presents the findings of the four-lane study and compares these to the results from the previous two-lane study. The scenario matrix consists of several dimensions including posted speed limit (45 and 55 mph, or 72 and 88 km/h), curb installation, lateral clearance between the edge of travel lane and the curb (2ft, 6 ft, and no- curb, or 0.6 m, 1.8 m, and no-curb), weather (clear and fog), traffic conditions in the next lane (1400 veh/hr and 400 veh/hr), etc. For each subject under different experimental scenarios, detailed driving parameters, such as driving speed and vehicle position in the travel lane, were recorded and analyzed subsequently. Results of the study suggest that driver behaviors are influenced by the various factors in a complex and interrelated manner. It is likely that drivers do not perceive the risk from the curb in determining their speed on four-lane rural highways. However, it is found that curbs may provide certain guidance to drivers, especially in selecting lane position. Comparing to the previous research in two-lane conditions, it is found that drivers are more likely to choose driving speeds according to posted speed limits, rather than roadway configurations. It is also found that the relative speed between driver’s vehicle and ambient traffic or curbs is an important factor determining drivers’ perception of risk and thus their driving behavior. The influence of subjective effects of these factors to their driving behavior is also observed in the study.
This paper presents the results of special-event route-diversion studies conducted in Dallas to evaluate 14 primary-candidate real-time messages that had resulted from extensive human-factors laboratory studies. The messages were displayed on matrix signs located on the freeway. The results of the study showed that all messages tested were effective in diverting freeway traffic to an arterial alternative route. The messages were equally effective before events that had fixed starting times (e.g., football games). Before events for which the arrival times were not set but spread over long periods of time (e.g., state fairs), some of the messages produced higher diversion rates than others, although all the messages resulted in high diversion rates. /Authors/
Findings of capacity studies conducted at urban freeway maintenance and construction work zones in Houston and Dallas are summarized. Studies were conducted on five-, four-, and three-lane freeway sections. The results indicate that the per-lane capacities are affected by the number of lanes open during the roadwork. For example, the average capacity on a three-lane section with two lanes open was 1500 vehicles per hour per lane (vphpl), whereas the average capacity with one lane open was only 1130 vphpl. Also illustrated is how the data can be used to estimate the effects of the lane closure. The results of the study can be used in scheduling work that involves lane closures on freeways. (Author)
Guidelines for selecting and installing active traffic control devices are beneficial to the practicing engineer who has responsibility for field installation and operation. This paper reports on a portion of the field installation and evaluation of two active traffic control devices for use at railroad-highway grade crossings. As a result, guidelines were developed for the use of a four-quadrant gate system and a highway traffic signal system for use at selected railroad-highway grade crossings. The characteristics of crossings that would be conducive to the use of a four-quadrant gate system and a highway traffic signal system were defined, with the objective of improving safety for the traveling public at the crossings. A four-quadrant gate system should be viewed as being between a standard gate system and a grade-separated crossing in terms of providing a level of safety to the traveling public. There are railroad-highway grade crossings that would not be economically feasible to grade separate, but a four-quadrant gate system would be cost-effective. Similarly, there are specific types of crossings that would receive a higher level of safety with the use of a highway traffic signal system and the upgrade would be cost-effective. The guidelines presented address the characteristics of the different types of crossings that would be appropriately served by these two active traffic control systems.
Recommendations for implementing speed control at construction and maintenance work zones are presented. The following implementation steps are identified and discussed: (a) determining the need for speed reduction, (b) selecting a reasonable speed, (c) selecting a speed control treatment based on effectiveness, practicality and cost, and (d) selecting a location for the speed control treatment implementation. Four speed control approaches are studied: flagging, law enforcement, changeable message signs, and effective lane width reduction. The advantages and disadvantages of each of these approaches are discussed. Limited cost data for each of the approaches are also presented. The conclusions and recommendations are based on the results of field studies and observations at numerous street and highway work zones in Texas.
Extensive mortality was observed among white-tailed deer (Odocoileus virginianus), but not mule deer (0. hemionus), in south-western North Dakota during the autumns of 1970 and 1971. It was estimated that at least 2,000 white-tailed deer died during the outbreak. The virus of epizootic hemorrhagic disease (EHD) of deer was isolated from a dead white-tailed deer and considered to be the etiologic agent responsible for the outbreak. Neutralizing antibodies to EHD were detected only in mule and white-tailed deer from the outbreak area. While a significantly higher percentage (P 0.05) of mule deer possessed EHD neutralizing antibodies, there were no differences by age or sex of the deer. The outbreak is discussed in relation to the known epizootiology of EHD. J. WILDL. MANAGE. 37(3):331-335 Beginning in late July or early August of 1970 and lasting until the first week of November, an epizootic of a hemorrhagic disease ravaged white-tailed deer herds in western North Dakota. Geographically, the epizootic area involved included the Little Missouri River drainage and the headwaters of streams to the east of it as well as parts of the lower Yellowstone River that border or are in North Dakota. Within this area, 195 deer carcasses were discovered and it is estimated that this represents not more than 10 percent of the deer which succumbed. Additionally, one sick mule deer and a few sick or dead pronghorn antelope (Antilocapra americana) were also found. The virus of infectious bovine rhinotracheitis (IBR) was isolated from an antelope but not from any of the deer (Richards 1972). During the summer of 1971 additional mortality was experienced within the epizootic area, but of a magnitude that was far less than during the 1970 epizootic. Most of these 1971 losses occurred in individual herds that had probably not been involved in 1970. The 1970 and 1971 die-offs occurred in the same area of North Dakota which experi nced extensive deer and antelope losses in 1962 (Fig. 1) (Richards 1963, 1964). The virus of epizootic hemorrhagic disease was considered to be the etiologic agent responsible for the 1962 epizootic. Tissue and serum samples collected from recently dead deer were submitted to the Department of Veterinary Science at the University of Wisconsin, Madison, for virus isolation studies. Also serum samples collected from hunter killed deer in 1970 and 1971 were tested for neutralizing antibodies to EHD virus and the closely related bluetongue virus (BT). This report concerns the results of these studies. MATERIALS AND METHODS Tissue and serum samples collected from four white-tailed deer found dead of hemorrhagic disease were submitted for virus isolation attempts. First, an attempt was made to reproduce the disease in a 5-month old male white-tailed deer. The liver, lung, and spleen collected from a yearling buck in Billings County within 1 hour after death were inoculated intravenously into the ex1 Research funded by Project W-67-R, Federal Aid to Wildlife Restoration Program. 2 Present address: Veterinary Public Health Section, Florida Division of Health, P.O. Box 210, Jacksonville, 32201. 3 Present address: Dean, College of Natural Resources, University of Wisconsin, Stevens Point, 54481. J. Wildl. Manage. 37 (3):1973 331 This content downloaded from 207.46.13.126 on Sat, 24 Sep 2016 04:50:42 UTC All use subject to http://about.jstor.org/terms 332 HEMORRHAGIC DISEASE IN DEER * Hoff et al. 1 2 3 4 6 7 a 13 10 11 12 13 14 15 16 17 is 19 21 22 3 24 2 2 b V A 29 3D 3 1 32 CAMT.1)II I 1 LlIn I w ln Ia ? ~ In Il r NES I 1 III L?lr II )1 L?r I I) ?L ll ? ) CWAN 31 .1-L n ?I L C1 ?I ???I 1I 111 1? 1 A 111 I . n L ~ LI l ?? ? I? U ~ I -1 11 CY LIl In~??n r ~ II In ?~I rl Irr u ?A
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