Evaluation of Highway Design Parameters on Influencing Operator Speeds through Casewise Visual Evaluation

Stamatiadis, Nikiforos; Bailey, Keiron; Grossardt, Theodore H.; Ripy, John

doi:10.3141/2195-15

Cited by 17 publications

(8 citation statements)

References 8 publications

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“…Past studies stressed the important role that landscapes and roadside elements such as vegetation, trees and guardrail barriers play in a driver's perception of the road and a driver's speed [38][39][40][41]. For this reason, to avoid confounding factors, the background pictures were the same in each driving course and the roadside configurations were the same in all sections (combined curves and reference curves) that were analyzed.…”

Section: Apparatusmentioning

confidence: 99%

Coordination of horizontal and sag vertical curves on two-lane rural roads: Driving simulator study

Bella

2015

IATSS Research

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a b s t r a c t a r t i c l e i n f o Available online xxxxThe highway geometric design guidelines for several countries provide suggestions for the coordination of horizontal curves overlapping with sag vertical curves (sag combinations) to avoid combined configurations that produce undesirable optical effects and reduced safety. Such suggestions are derived from studies based on the drawing of the perspective of the road. This drawing method is severely limited with respect to the simulation of the perspective view of the highway to the driver during the dynamic task of driving. Interactive driving simulation methods are deemed to be more efficient for these objectives. This paper reports the results of a study carried out using an interactive driving simulator to evaluate the effects on the driver's speed behavior of different configurations of sag combinations and non-combined curves on a flat grade with the same features as the horizontal curves of the sag combinations (reference curves). The speed behaviors of drivers along the tangent-curve transitions of sag combinations and reference curves were recorded. The speed on the approach tangent, the speed at the midpoint of the horizontal curve and the maximum speed reduction (MSR), the difference between the maximum speed on the last 200 m of the approach tangent and the minimum speed on the first half of the horizontal curve, were analyzed. One-way repeated MANOVA was performed to determine if the driver's speed behavior on the horizontal curves was influenced by different configurations of sag combinations and reference curves. The primary result was that on suggested sag combinations, the driver's speed behavior did not differ in any statistically significant way from that on the reference curves. Whereas the critical sag combinations (configurations that should be avoided) caused high values of maximum speed reduction along the tangent-curve transition, which pointed to the driver's reaction to an incorrect perception of the road alignment. Therefore, this result confirmed the effectiveness of the road design guidelines for the coordination of horizontal curves and sag vertical curves.

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Section: Apparatusmentioning

confidence: 99%

Coordination of horizontal and sag vertical curves on two-lane rural roads: Driving simulator study

Bella

2015

IATSS Research

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“…Stamatiadis et al affirmed that excessive speed is one of the primary safety hazards facing highway users (7). Too often operating speeds exceed design speeds, and speed limits are generally ignored by drivers.…”

Section: Literature Reviewmentioning

confidence: 99%

Driver Speed Behavior on Circular Curves of Undivided Two-Lane Rural Roads

Russo

Fric

Biancardo

et al. 2015

Transportation Research Record: Journal of the Transportation R

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Many researches have proved that one of the parameters that most influence the safe driving is the operating speed defined as the speed at which drivers travel on a dry road in free flow conditions during daylight hours. This study describes a comparison between the driver speed behavior on horizontal circular curves located in Serbia and the driver speed behavior on circular curves located in Italy with analogous infrastructural-geometric contexts. Only curves falling within two-lane rural roads network in low-volume conditions without spiral transition curves have been studied. Operating speed profiles were plotted and a careful analysis was carried out to study the deceleration/acceleration motion at each selected curve. Speed measurements were conducted by using different devices: a) for Italian case, laser detectors were used that emit and receive a pair of laser beams perpendicularly to the road’s axis and they record the instantaneous vehicle speed; b) for Serbian case, sensors were used with an applicant software developed in the LabVIEW programming environment and signals logged in a binary file for which the vehicle speed is measured on basis of the passing time between two consecutive sensors along the curve. Two driver behavior types were found: a) drivers that decelerate approaching the middle of the curve and accelerate leaving it; b) drivers that decelerate on the whole circular curve length. T-test was performed. Statistically, no significant difference was produced from the analysis when circular curves are located in different states which reflect the same geometric, traffic and environmental context

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“…Drivers' pupil sizes vary in response to visual and environmental transitions at tunnel portals, including tunnel alignment, visual reference objects, and illuminance (13). The alignment at tunnel portals should maintain a consistent distance of more than 3 s, according to the Chinese industry standard.…”

Section: Literature Reviewmentioning

confidence: 99%

Safety Evaluation of Illuminance Transition at Highway Tunnel Portals on Basis of Visual Load

Huang

Pan

2014

Transportation Research Record: Journal of the Transportation R

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Highway tunnel entrances and exits are accident-prone locations, especially in the daytime, primarily because of the sharp transitions in lighting in these areas. Therefore, a rational assessment of lighting transitions at tunnel portals is the key to ensuring traffic safety. This study used the EMR-8B eye-tracker system to monitor the pupil changes of eight selected drivers as they drove through 26 typical highway tunnels. The test results showed a power function relationship between drivers’ pupil areas and pupil illuminance at highway tunnel portals. A quantitative relationship between the pupil area and its critical velocity was also established, and the ratio ( k) of the pupil area's changing rate in relation to its critical velocity was used to assess the visual load and to further evaluate the lighting transitions. The results demonstrated that ( a) the relationship between pupil illuminance at the tunnel portal and the driver's pupil area conformed to Stevens’ law from experimental psychology, ( b) the relationship between the driver's pupil area and its critical velocity followed the quadratic function, ( c) the visual load at a tunnel entrance was heavier than that at the tunnel exit, and ( d) the severe transitions in pupil illuminance within 10 m of some existing highway tunnel entrances caused a great visual load, and thus are urgently in need of improvement.

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Evaluation of Highway Design Parameters on Influencing Operator Speeds through Casewise Visual Evaluation

Cited by 17 publications

References 8 publications

Coordination of horizontal and sag vertical curves on two-lane rural roads: Driving simulator study

Coordination of horizontal and sag vertical curves on two-lane rural roads: Driving simulator study

Driver Speed Behavior on Circular Curves of Undivided Two-Lane Rural Roads

Safety Evaluation of Illuminance Transition at Highway Tunnel Portals on Basis of Visual Load

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