scholarly journals Driver Response to a Dynamic Speed Feedback Sign on Freeway Exit Ramps Based on Sign Location, Interchange Type, and Time of Day

2021 ◽  
pp. 036119812110152
Author(s):  
Md Shakir Mahmud ◽  
Matthew Motz ◽  
Travis Holpuch ◽  
Jordan Hankin ◽  
Anthony J. Ingle ◽  
...  
Keyword(s):  
Time Of Day ◽  
Light Conditions ◽  
Driver Response ◽  
Beneficial Effects ◽  
Passenger Vehicles ◽  
System Versus ◽  
Feedback Sign ◽  
Speed Selection ◽  
Peak Versus ◽  
Horizontal Curvature

A series of field evaluations was performed at three freeway interchange ramps in Michigan that possessed significant horizontal curvature to assess the impacts of a dynamic speed feedback sign (DSFS) on driver speed selection and brake response while approaching and entering the ramp curve. A DSFS with a 15 in. full-matrix display was temporarily installed at each of the three exit ramp locations. The sign was programmed to display the same feedback message at each location, which included the speed number for all approaching vehicles, which alternated with a “Slow Down” message for vehicles approaching above 40 mph. The effectiveness of the feedback sign was tested across various sign locations (at the point of curvature versus 350 ft upstream), interchange types (system versus service), time of day (peak versus off-peak), light conditions (daylight versus darkness), and vehicle types (passenger vehicles versus trucks). Compared with the pre-DSFS site condition, the DSFS reduced curve entry speeds and improved brake response at two of the three ramp locations. In general, the greatest beneficial effects on driver behavior were achieved when the DSFS was positioned at the point of curvature, during which curve entry speeds were reduced by approximately 2 mph. These findings were consistent between the system interchanges and service interchanges, and across all vehicle types. The DSFS was also found to be most effective during daytime off-peak periods compared with peak periods and at night. Further evaluation of DSFS at additional ramp locations, and considering an expanded set of conditions, is recommended.

scholarly journals Evaluating Driver Response to a Dynamic Speed Feedback Sign at a Freeway Exit Ramp Considering the Sign Design Characteristics and Lateral Installation Position

2021 ◽  
Author(s):  
Shakir Mahmud ◽  
Babak Safaei
Keyword(s):  
Lateral Position ◽  
Sign Test ◽  
Detection Range ◽  
Speed Reduction ◽  
Driver Response ◽  
Feedback Sign ◽  
Improved Performance ◽  
Design Characteristics ◽  
Horizontal Curvature ◽  
Exit Ramp

Research was conducted at a freeway exit ramp with significant horizontal curvature to evaluate the effectiveness of dynamic speed feedback signs (DSFS) as a speed reduction countermeasure. Several aspects of the DSFS were evaluated, including display size, border type, lateral installation position, and vehicle detection range. Three different full-matrix DSFS were utilized, which included: 15-inch display panel with yellow border, 18-inch display panel with yellow border, and 18-inch display panel with no border. Each sign was individually installed and tested at identical locations near the start of the exit ramp curve, in both the traditional right-side-mount and an alternative forward-mount within the exit gore area. Speed data and message activation location were collected for vehicles approaching and entering into the curve across the various sign test conditions. Overall, the presence of a DSFS positioned near the start of the curve resulted in curve entry speeds that were, on average, 3.5 mph lower than without a DSFS present at the site. The lowest curve entry speeds were observed for cases where the message activated when vehicles were within 250 to 400 ft of the curve. Interestingly, earlier message activation did not contribute to further speed reductions, although later activation substantially diminished the speed reduction effects. Regarding DSFS lateral position, both the side-mounted and forward-mounted DSFS installations resulted in similar curve entry speeds. Furthermore, there were no discernable differences in curve entry speeds between the 15-inch and 18-inch display panels, although the inclusion of a yellow sign border improved performance.

scholarly journals Driver Response to a Dynamic Speed Feedback Sign on Freeway Exit Ramps based on Sign Location, Interchange Type, and Time of Day

2020 ◽  
Author(s):  
Shakir Mahmud ◽  
Matthew Motz ◽  
Travis Holpuch ◽  
Anthony J. Ingle ◽  
Timothy Gates ◽  
...  
Keyword(s):  
Substantial Reduction ◽  
Light Condition ◽  
Field Evaluation ◽  
Time Of Day ◽  
Speed Reduction ◽  
Driver Response ◽  
Horizontal Curves ◽  
Before And After ◽  
Feedback Sign ◽  
Straight Segments

Roadway segments that include horizontal curves experience a disproportionate number of crashes compared to straight segments. Many of these crashes are lane departure-related, and excessive speed is often a contributing factor. One particularly vulnerable area for such crashes is freeway interchange ramps, which require a substantial reduction in speed to be safely negotiated. While dynamic speed feedback signs (DSFS) have been found to be an effective speed and crash reduction countermeasure at horizontal curves, the use of such signs on freeway interchange ramps has been limited nationwide. Consequently, the effectiveness of DSFS as a speed reduction countermeasure in such settings has remained largely untested. A before-and-after field evaluation was performed at three freeway exit ramps to assess the impacts of a DSFS on driver speed selection and braking characteristics while approaching and entering the ramp curves. The effectiveness of the feedback sign was tested across various conditions, including sign location, interchange type, time of day, light condition, and vehicle type. In general, the greatest benefits to driver behavior were achieved with the DSFS positioned at the point of curvature, during which curve entry speeds were reduced by approximately 2 mph compared to the pre-DSFS condition. These findings were consistent between the system- and service-interchanges and across all vehicle types. The DSFS was also found to be most effective during daytime off-peak periods compared to peak periods and at night. Based on the study findings, the continued use of DSFS as a speed reduction treatment at freeway exit ramps is recommended.

Evaluation of Alternative Messages and Sign Locations on Driver Response to a Dynamic Speed Feedback Sign on a Freeway Interchange Ramp

2020 ◽  
Vol 2674 (12) ◽  
pp. 530-541
Author(s):  
Timothy J. Gates ◽  
Md Shakir Mahmud ◽  
Anthony J. Ingle ◽  
Matthew Motz ◽  
Travis Holpuch ◽  
...  
Keyword(s):  
Driver Behavior ◽  
Field Evaluation ◽  
Speed Reduction ◽  
Driver Response ◽  
Heavy Trucks ◽  
Warning Message ◽  
Feedback Sign ◽  
Speed Management ◽  
Speed Selection ◽  
Advisory Speed

Research was undertaken to determine effective messaging strategies and sign positions for dynamic speed feedback signs (DSFS) when used for speed management at freeway ramp curves. A field evaluation was performed in this setting to assess the impacts of a DSFS on driver speed selection and braking characteristics while approaching and entering the curve. Three feedback messaging strategies were evaluated at three sign positions in advance of the curve. Compared with the existing site (without the DSFS), the DSFS reduced curve entry speeds and improved brake response across all test conditions, particularly for heavy trucks. Overall, considering the combination of both sign position and feedback messaging strategy, the greatest benefits to driver behavior were attained when the DSFS was positioned 255 ft upstream of the curve and the feedback message included the speed number alternating with a SLOW DOWN message. The inclusion of an advisory speed panel with the DSFS did not have a substantive impact on driver behavior. Based on the findings, the continued use of DSFS as a speed reduction treatment at freeway ramp curves is recommended. Specifically, the sign should be positioned to provide adequate time for drivers to perceive and react to the message, such that comfortable braking can be accommodated while approaching the curve. However, the sign should not be placed too far in advance of the curve, as drivers may be more likely to disregard such a premature warning message. Further evaluation of DSFS under various alternative ramp configurations is recommended.

Phase-advance shifts of human circadian pacemaker are accelerated by daytime physical exercise

2001 ◽  
Vol 281 (1) ◽  
pp. R197-R205 ◽  
Author(s):  
Toshihiko Miyazaki ◽  
Satoko Hashimoto ◽  
Satoru Masubuchi ◽  
Sato Honma ◽  
Ken-Ichi Honma
Keyword(s):  
Physical Exercise ◽  
Single Pulse ◽  
Time Of Day ◽  
Phase Advance ◽  
Circadian Pacemaker ◽  
Light Conditions ◽  
Melatonin Rhythm ◽  
Dim Light ◽  
The Difference ◽  
Isolation Facility

Effects of forced sleep-wake schedules with and without physical exercise were examined on the human circadian pacemaker under dim light conditions. Subjects spent 15 days in an isolation facility separately without knowing the time of day and followed a forced sleep-wake schedule of a 23 h 40-min period for 12 cycles, and physical exercise was imposed twice per waking period for 2 h each with bicycle- or rowing-type ergometers. As a result, plasma melatonin rhythm was significantly phase advanced with physical exercise, whereas it was not changed without exercise. The difference in phase was already significant 6 days after the start of exercise. The amplitude of melatonin rhythm was not affected. A single pulse of physical exercise in the afternoon or at midnight significantly phase delayed the melatonin rhythms when compared with the prepulse phase, but the amount of phase shift was not different from that observed in the sedentary controls. These findings indicate that physical exercise accelerates phase-advance shifts of the human circadian pacemaker associated with the forced sleep-wake schedule.

scholarly journals Environment and Sporulation in Phytopathogenic Fungi IV. The Effect of Light on the- Formation of Conidia of Peronospora Tabacina Adam

1963 ◽  
Vol 16 (1) ◽  
pp. 88 ◽  
Author(s):  
IAM Cruickshank
Keyword(s):  
Light Source ◽  
Monochromatic Light ◽  
Continuous Light ◽  
Visible Spectrum ◽  
Phytopathogenic Fungi ◽  
Time Of Day ◽  
Light Conditions ◽  
Low Light ◽  
Maximal Inhibition ◽  
Effect Of Light

Using a leaf�disk technique, an analysis of the effect of light on the sporulation intensity of P. tabacina was carried out. The following points were demonstrated: (I) Under conditions of continuous light, sporulation of P. tabacina is sensitive to very low light intensities. ED5!1 for inhibition of sporulation was 16 ftvV cm- 2 for incandescent light (4 f,c.), and 0�58 p.W cm-2 for a monochromatic light source (469 mpo) in the region of maximum effectiveness. (2) Dark treatments induced sporulation under otherwise continuous light conditions. The response was directly proportional to the length of the exposure to darkness over the period 1�5-7 hr. (3) The time of day at which sporulation occurred could be modified by adjustment of the time of day at which darkness was initiated. (4) Within the visible spectrum, the region exerting maximal inhibition on sporulation occurred at 450-525 mJL.

Evaluation of Cycloate Followed by Evening Two-Leaf–Stage Phenmedipham Application in Fresh Market Spinach

2016 ◽  
Vol 30 (2) ◽  
pp. 464-471 ◽  
Author(s):  
Ran N. Lati ◽  
Beiquan Mou ◽  
John S. Rachuy ◽  
Steven A. Fennimore
Keyword(s):  
Light Intensity ◽  
Weed Control ◽  
Growing Season ◽  
Field Studies ◽  
High Light Intensity ◽  
Time Of Day ◽  
Light Conditions ◽  
Fresh Market ◽  
Reference Treatment ◽  
Leaf Stage

Fresh market spinach has one primary herbicide, cycloate, which does not control all weeds. Previous studies demonstrated that cycloate PRE followed by (fb) phenmedipham at the four-leaf spinach stage is a safe and effective treatment. However, this treatment is not useful for the main growing season of fresh spinach due to its short crop cycle and the 21-d preharvest interval requirement of phenmedipham. This study evaluates the potential to use the combination of cycloate PRE fb phenmedipham on two-leaf spinach. Greenhouse and field studies were conducted in 2014 using three spinach varieties with low (‘Nordic' and ‘Sardinia') and high (‘Regal') tolerance to phenmedipham. Greenhouse studies revealed that phenmedipham at 90 g ai ha−1was safe to Regal when applied at the two-leaf stage. Sardinia was more susceptible to phenmedipham injury under high (310 W m−2) light conditions than low (258 W m−2) light conditions. Impact of time of day on phenmedipham safety was evaluated in the field: day-long exposure to high light intensity following morning applications vs. evening applications fb exposure to low light intensity. Injury estimations taken 3 d after treatment (DAT) were lower for evening than for morning applications. Nonetheless, injury 11 DAT and spinach yield evaluations found no differences between morning and evening applications. Subsequently, cycloate (1,700 g ha−1) PRE fb phenmedipham (90 and 180 g ha−1) applied in the evening at the two-leaf stage was evaluated. A reference treatment was cycloate PRE fb phenmedipham (270 g ha−1) at the four-leaf stage. Treatments with cycloate fb two-leaf phenmedipham at 90 and 180 g ha−1were safe to spinach and improved weed control compared to cycloate alone. Cycloate fb 180 g ha−1phenmedipham at the two-leaf stage reduced weed biomass by 88% compared to cycloate alone. This level of weed control was similar to the reference treatment. Results here show that phenmedipham applied at the two-leaf stage is safe to fresh market spinach and it has the potential to be used during most of the fresh spinach growing season.

The impact of weather, road surface, time-of-day, and light conditions on severity of bicycle-motor vehicle crash injuries

2018 ◽  
Vol 61 (7) ◽  
pp. 556-565 ◽  
Author(s):  
Morteza Asgarzadeh ◽  
Dorothee Fischer ◽  
Santosh K. Verma ◽  
Theodore K. Courtney ◽  
David C. Christiani
Keyword(s):  
Motor Vehicle ◽  
Time Of Day ◽  
Motor Vehicle Crash ◽  
Road Surface ◽  
Light Conditions ◽  
Vehicle Crash ◽  
Surface Time ◽  
Crash Injuries ◽  
The Impact

Involvement of phytochrome in regulation of transpiration: red-/far red-induced responses in the chlorophyll-deficient mutant of pea

2003 ◽  
Vol 30 (12) ◽  
pp. 1249 ◽  
Author(s):  
Svetlana V. Sokolskaya ◽  
Natalia V. Sveshnikova ◽  
Galina V. Kochetova ◽  
Alexei E. Solovchenko ◽  
Sergei A. Gostimski ◽  
...  
Keyword(s):  
Red Light ◽  
Time Of Day ◽  
Constant Darkness ◽  
Deficient Mutant ◽  
Light Conditions ◽  
Wild Type ◽  
Rates Of Change ◽  
Acute Response ◽  
Dependent Component ◽  
Aurea Mutant

Transpiration rhythmicity and intensity were investigated in the chlorophyll-deficient mutant XL18 of Pisum sativum L. and in the phytochrome-deficient mutant aurea of Lycopersicon esculentum Mill. A custom-built psychrometer was used. In the XL18 mutant an acute transpiration response to monochromatic irradiation was observed such that red (R) light increased and far-red (FR) decreased transpiration rate, with equal rates of change. This result indicates that phytochrome is involved in regulation of transpiration. In wild type pea the chlorophyll-dependent component of transpiration was also shown to involve phytochrome. Monochromatic irradiation by red or far-red light induced an increase in transpiration with acceleration dependent on time of day. The response was irreversible by light of either wavelength. We conclude that both photoreceptors are involved in the acute response. Investigation of the daily course of transpiration revealed rhythmic changes in wild type pea and tomato under natural light conditions and in constant darkness. The rhythm was not apparent in the XL18 mutant in constant darkness, or in the aurea mutant under natural illumination. The latter results show that phytochrome, as a photoreceptor, is essential for maintaining the rhythm upon irradiation, while the photosynthetic component is crucial in darkness.

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