Visibility of Yellow Center Line Pavement Markings as a Function of line Configuration and Line Width

1996 ◽  
Vol 40 (18) ◽  
pp. 919-922 ◽  
Author(s):  
Helmut T. Zwahlen ◽  
Thomas Schnell
Keyword(s):  
Line Width ◽  
Finite Length ◽  
Fold Increase ◽  
Center Line ◽  
Detection Distance ◽  
Pavement Markings ◽  
Upper Limit ◽  
Line Configuration ◽  
Line Type

The end detection distance of finite length yellow center lines (tape, no edge lines included) was determined in the field at night under automobile low beam illumination as a function of the line configuration (single dashed, single solid, and double solid) and width (0.05m, 0.1m). Ten subjects were used in the study. The factor line type (configuration and width), and approach direction were statistically significant. A 16 fold increase in the retro-reflective area resulted in a near 100% average end detection distance increase in the westbound direction, and in a 65% average end detection distance increase in the eastbound direction (different backgrounds). The findings confirm that an about 65% to near 100% increase in the average end detection distance represents the approximate upper limit of what can be achieved by adding more retro-reflective area to a yellow center line. Increasing the material retroreflectivity and/or improving the material angularity might be much more effective to increase the detection distance.

Visibility of New Dashed Yellow and White Center Stripes as Function of Material Retroreflectivity

1996 ◽  
Vol 1553 (1) ◽  
pp. 73-80 ◽  
Author(s):  
Helmut T. Zwahlen ◽  
Thomas Schnell
Keyword(s):  
Finite Length ◽  
Environmental Concerns ◽  
Vehicle Speed ◽  
Detection Distance ◽  
Left Edge ◽  
Pavement Markings ◽  
Industry Standards ◽  
Visibility Distance ◽  
Continued Use ◽  
Pavement Marking

Economic and environmental concerns have raised questions about the continued use of yellow center lines on two-lane highways and yellow left-edge lines on divided highways or freeway entrance and exit ramps. The use of yellow pavement markings as a warning to indicate opposing traffic appears to be a concept that is compatible with certain human factors population stereotypes and accepted industry standards (yellow for caution), but it is unclear how well the general driver population understands the message conveyed by yellow pavement markings. Another question is how the visibility of yellow center lines or left-edge lines compares with the visibility of similar white pavement markings. The effects of color (white and yellow) and material retroreflectivity (low, medium, and high) on the end detection distance of finite-length center lines at night under automobile low-beam illumination were determined. Ten subjects were used in a field experiment (rural, automobile low-beam conditions) to obtain the end detection distances of finite-length center stripes of 0.1-m width. The data show that the end detection distances of new yellow dashed center stripes and new white dashed center stripes are about the same. The average end detection distance was 30 to 35 m for the low-retroreflectivity material and about 62 m for the high-retroreflectivity material (four- to fivefold retroreflectivity increase). It is tentatively concluded that the use of white center stripes most likely will not result in a significant increase in the end detection distance when compared with the use of similar yellow center stripes. It is also tentatively concluded that an increase in the retroreflectivity of the pavement marking materials will result in a significant and desirable increase of the visibility distance, but to provide a minimum preview time of 3.6 sec (at a vehicle speed of 90 km/hr), even higher-retroreflectivity materials than the ones used in this study will be required.

Visibility of New Centerline and Edge Line Pavement Markings

1997 ◽  
Vol 1605 (1) ◽  
pp. 49-61 ◽  
Author(s):  
Helmut T. Zwahlen ◽  
Thomas Schnell
Keyword(s):  
Ohio University ◽  
Detection Distance ◽  
Pavement Markings ◽  
Upper Limit ◽  
Distance Data ◽  
Left And Right ◽  
Pavement Marking ◽  
Main Effects ◽  
Road Marking

The objective of the presented two-part study was to provide nighttime pavement-marking visibility data obtained under automobile low-beam illumination conditions in the field for further calibration of the Ohio University pavement-marking visibility model CARVE (Computer Aided Road Marking Visibility Evaluator). A total of 10 subjects participated in Part 1 of the study. The goal of Part 1 was to determine the end-detection distance of finite-length, new, medium-retroreflectivity, yellow pavement marking tape centerlines without edge lines as a function of the centerline configuration (single dashed, single solid, and double solid) and width. The results of Part 1 confirm that an increase in the average end-detection distance of about 55 percent represents the approximate upper limit of what can be achieved by adding more retro-reflective area to a yellow centerline. Part 2 consisted of four main experiments involving 10 subjects each and two follow-up experiments involving a total of 10 subjects. The goal of Part 2 was to provide pavement-marking end-detection distance data for fully marked roads consisting of left and right white edge lines with either a yellow double solid or single dashed centerline. The main effects of width, retroreflectvity, and centerline configuration were found to be statistically significant. A fully marked road consisting of both edge lines and a centerline generally appears to provide end-detection distances that are on average about twice as long as the end-detection distances that can be achieved with a centerline alone, without edge lines.

Latch-Up Induced Slit Voiding in Aluminum Metal Lines

1999 ◽  
Author(s):  
Chunyu Zhang ◽  
Lakshmi Vedula ◽  
Shekhar Khandekar
Keyword(s):  
High Temperature ◽  
Line Width ◽  
Fold Increase ◽  
Metal Line ◽  
Operating Life ◽  
Mixed Signal ◽  
Aluminum Metal ◽  
Temperature Operating ◽  
Latch Up

Abstract Latch-up induced during High Temperature Operating Life (HTOL) test of a mixed signal device fabricated with 1.0 μm CMOS, double poly, double metal process caused failures due to an open in aluminum metal line. Metal lines revealed wedge voids of about 50% of the line width. Triggering of latch up mechanism during the HTOL test resulted in a several fold increase of current flowing through the ground metal line. This increase in current resulted in the growth of the wedge voids leading to failures due to open metal lines.

Assessment of Durability of Wet Night Visible Pavement Markings

2013 ◽  
Vol 2337 (1) ◽  
pp. 67-73 ◽  
Author(s):  
Ronald B. Gibbons ◽  
Brian Williams ◽  
Benjamin Cottrell
Keyword(s):  
Human Factors ◽  
Research Effort ◽  
Detection Distance ◽  
Separate Paper ◽  
Pavement Markings ◽  
Diminishing Returns ◽  
Pavement Marking ◽  
Relationship Of ◽  
The Relationship

This paper describes the visibility experiment conducted as part of a research effort to establish the durability of pavement markings in an on-road installation. Six marking technologies were installed on a portion of Route 460 in Blacksburg, Virginia. A human factors experiment in natural rain conditions was performed to establish the visibility needs of the driver. The retroreflectivity of the markings was measured at intervals of 2 to 5 months, with six measurements over the course of 23 months (these data are discussed in a separate paper). Previous research suggested that a minimum retroreflectivity of 150 mcd/m2/lx should be maintained to meet drivers' visibility needs. As part of this research, a human factors experiment was conducted to test the validity of this recommendation. The distance at which participants could detect the end of a pavement marking was measured as well as the retroreflectivity of the marking at those points. The relationship of detection distance and retroreflectivity found in this study suggests that as retroreflectivity increases beyond 150 mcd/m2/lx, there are diminishing returns on detection distance. This finding suggests that the recommended minimum is appropriate for providing increased visibility for drivers, while keeping retroreflectivity requirements at a reasonable level for marking manufacturers.

scholarly journals CO Observations of High-z Objects

1999 ◽  
Vol 183 ◽  
pp. 159-159
Author(s):  
K. Ohta ◽  
K. Nakanishi ◽  
M. Akiyama ◽  
T.T. Takeuchi ◽  
T. Yamada ◽  
...  
Keyword(s):  
Physical Properties ◽  
Line Width ◽  
Conversion Factor ◽  
Line Ratio ◽  
Molecular Gas ◽  
Nearby Star ◽  
Gas Density ◽  
Upper Limit ◽  
The Mean ◽  
Co Observations

We have made a CO (J=2−1) observation using the Nobeyama 45m telescope aimed at examining physical properties of the molecular gas in the object. Upper limit obtained is 1.8 mK (3σ) at a velocity resolution of 100 km s−1, which leads to an upper limit on the molecular gas mass of 5.3 × 1011M⊙, if we assume a line width of 250 km s−1 obtained in J = 5–4 line and the Galactic CO-to-H2 conversion factor of 4.5 M⊙ K km s−1 pc2. The line ratio between 2–1 line and 5–4 line as well as those from 7–6 and 4–3 lines (Omont et al. 1996) imply that the mean gas density is as high as 103–5 cm−3, which is comparable to that in nearby star burst galaxies (e.g., Solomon et al. 1992).

scholarly journals Notizen:Hyperfeinstruktur von CsCl

1972 ◽  
Vol 27 (10) ◽  
pp. 1516-1517
Author(s):  
J. Hoeft ◽  
E. Tiemann ◽  
T. Törring
Keyword(s):  
Hyperfine Structure ◽  
Line Width ◽  
Quadrupole Coupling Constant ◽  
Rotational Transition ◽  
Coupling Constants ◽  
Coupling Constant ◽  
Vibrational States ◽  
Upper Limit ◽  
Quadrupole Coupling ◽  
Rotational Transitions

Abstract The quadrupole hyperfine structure of 133Cs35Cl was measured on the rotational transition J=1 → 2 at 8.6 GHz. The calculated quadrupole coupling constants of 35Cl in various vibrational states are reported. The observed line width of the rotational transitions yields an upper limit of the quadrupole coupling constant of 133Cs.

scholarly journals Effects of Narrow Linear Disturbances on Light and Wind Patterns in Fragmented Boreal Forests in Northeastern Alberta

Forests ◽  
2018 ◽  
Vol 9 (8) ◽  
pp. 486 ◽  
Author(s):  
Eleanor Stern ◽  
Federico Riva ◽  
Scott Nielsen
Keyword(s):  
Light Intensity ◽  
Forest Fragmentation ◽  
Line Width ◽  
Fold Increase ◽  
Anthropogenic Disturbances ◽  
Abiotic Conditions ◽  
Maximum Wind ◽  
Wind Speeds ◽  
Average Wind ◽  
Seismic Lines

Forest fragmentation threatens forest biodiversity and ecosystem function. One of the concerns relates to increases in edge effects, which among other things affects the forest microclimate that influences the distribution and behavior of species. In Alberta, Canada, boreal anthropogenic disturbances from in situ oil exploration are increasing forest fragmentation, especially in the form of exploratory well pads and seismic lines (i.e., linear forest clearings created during the exploration phase of oil extraction). Dissection of these forests by seismic lines has the potential to change local patterns in wind and light, and thus may alter forest communities. Although alterations of these abiotic conditions are likely, the magnitude of these changes is unknown, particularly the effects of changes in the width and orientation of linear disturbances. Here we investigated changes in light and wind on seismic lines compared to that of adjacent undisturbed forests and nearby cleared openings. Specifically, we examined how seismic line characteristics (i.e., line direction, line width, and adjacent canopy height) altered local responses in these abiotic conditions. Generalized Linear Mixed Effect models predicted a 2-fold increase in average light intensity and maximum wind speeds, and a 4-fold increase in average wind speeds on seismic lines compared to adjacent forests. These changes did not approach the conditions in large openings, which compared to forests had a 3-fold increase in average light intensity, a 16-fold increase in average wind speeds, and a 4-fold increase in maximum wind speeds. Line width and orientation interacted with adjacent forest height altering the abiotic environment with wider lines having a 3-fold increase on maximum wind speed. We conclude that even localized, narrow (<10-m wide) forest disturbances associated with oil sands exploration alter forest microclimatic conditions. Recent changes in practices that reduce line width as well as promoting tree regeneration, will minimize the environmental effects of these anthropogenic disturbances.

scholarly journals The effect of aggregation on visibility in open water

2016 ◽  
Vol 283 (1839) ◽  
pp. 20161463 ◽  
Author(s):  
Graeme D. Ruxton ◽  
Sönke Johnsen
Keyword(s):  
Open Water ◽  
Fold Increase ◽  
Life History Trait ◽  
Detection Distance ◽  
Common Life ◽  
Predator Prey ◽  
Qualitative Understanding ◽  
Trophic Webs ◽  
Risk Dilution ◽  
Water Species

Aggregation is a common life-history trait in open-water taxa. Qualitative understanding of how aggregation by prey influences their encounter rates with predators is critical for understanding pelagic predator–prey interactions and trophic webs. We extend a recently developed theory on underwater visibility to predict the consequences of grouping in open-water species in terms of increased visual detection of groups by predators. Our model suggests that enhanced visibility will be relatively modest, with maximum detection distance typically only doubling for a 100-fold increase in the number of prey in a group. This result suggests that although larger groups are more easily detected, this cost to aggregation will in many cases be dominated by benefits, especially through risk dilution in situations where predators cannot consume all members of a discovered group. This, in turn, helps to explain the ubiquity of grouping across a great variety of open-water taxa.

Human Factors Assessment of Pavement Marking Retroreflectivity in Simulated Rain and Dry Conditions

2021 ◽  
pp. 036119812110111
Author(s):  
Timothy P. Barrette ◽  
Adam M. Pike
Keyword(s):  
Human Factors ◽  
Subjective Rating ◽  
Detection Distance ◽  
Pavement Markings ◽  
Dry Conditions ◽  
Simulated Rain ◽  
Pavement Marking ◽  
Over Time

Pavement marking retroreflectivity standards are typically developed with dry conditions in mind, however, driving at night during rainfall is seemingly one of the most challenging and stressful situations for a driver. Furthermore, existing research indicates continuous wet retroreflectivity is relatively weakly correlated with dry retroreflectivity and deteriorates differently over time, leading to the obvious conclusion that dry retroreflectivity standards alone are not enough to ensure that pavement markings meet the needs of drivers across the breadth of roadway conditions that may occur. Consequently, developing standards for minimum continuous wet retroreflectivity for new installations and for maintenance purposes represents an important area for research. This study aims to develop new installation and maintenance values for continuous wet retroreflectivity based on a multifaceted, closed-course study of detectability of pavement markings in simulated rain and dry conditions. A series of 20 pavement marking samples was evaluated in relation to detection distance and subjective rating. The results of the study indicated that pavement markings need to be maintained at a continuous wet retroreflectivity value of 50 mcd/m2/lux based on a participant pool that skewed older in age, but that likely represents something close to the 85th-percentile driver. Additional salient findings included observed wet retroreflectivity loss in the existing literature of approximately 7% per month, as well as the maximum preview time in simulated rain conditions being substantially lower than in dry conditions.

scholarly journals CO Observations of High-z Objects

1999 ◽  
Vol 186 ◽  
pp. 362-362
Author(s):  
K. Ohta ◽  
K. Nakanishi ◽  
M. Akiyama ◽  
T.T. Takeuchi ◽  
T. Yamada ◽  
...  
Keyword(s):  
Physical Properties ◽  
Line Width ◽  
Rest Frame ◽  
Conversion Factor ◽  
Molecular Gas ◽  
Nearby Star ◽  
Gas Density ◽  
Upper Limit ◽  
The Mean ◽  
Co Observations

We have made a CO(J=2-1) observations using the Nobeyama 45m telescope aimed at examining the physical properties of the molecular gas in this object. The upper limit obtained is 1.8 mK (3σ) at a velocity resolution of 100 km s−1, which leads to an upper limit on the molecular gas mass of 5.3 × 1011M⊙, if we assume a line width of 250 km s−1 obtained in the CO(J = 5 - 4) line (rest-frame) and the Galactic CO-to-H2 conversion factor of 4.5 (M⊙ K km s−1 pc2). The line ratio between the 2–1 line and the 5–4 line as well as those from the 7–6 and the 4–3 lines (Omont et al. 1996, Nature, 382, 428) imply that the mean gas density is as high as 103–5 cm−3, which is comparable to that in nearby star burst galaxies (e.g., Solomon et al. 1992, ApJ, 387, L55).

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