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UBC Theses and Dissertations
Redirection effectiveness of roadside curbs Lafond, Nadine
Abstract
Curbs are commonly used along urban streets, in channelised intersections, and along medians and ramps. One of its purposes is to protect pedestrians. The protection offered by a curb is measured by its ability to redirect errant vehicles. A curb redirection effectiveness depends upon the speed and the angle of impact of a vehicle, the height of the curb, the vehicle mass, and the tire radius. The effectiveness is also influenced by other factors such as the coefficient of friction between the tire and the curb, the tire pressure, and the geometric design of the curb. The redirection ability of a 152 mm high curb of type C design from the AASHTO Manual was investigated during 28 full scale tests. Six vehicles, of a mass between 675 and 1750 kg, impacted the curb at a speed varying from 6 to 34 km/h, at angles of 5°, 10°, or 15°. Four tests were performed to evaluate scrubbing conditions and a 90° impact. Mass was added to some vehicles to measure the influence of the mass without modifying vehicle dimension and properties. It was found that a type C curb does not provide an appropriate protection to pedestrians since it can easily be crossed when the component of the velocity normal to the curb exceeds 2 km/h. Redirection was not achieved in any of the tests performed at an impact angle of 15°. According to the tested data, the probability that a vehicle is not redirected by the curb starts at an impact speed of 10 km/h and reaches 100% at a speed of 40 km/h when approaching the curb at a 5° angle. An equation relating redirection speed to the impact angle, the curb height, and the studied vehicle parameters, was validated. A safe curb height of 205 mm is suggested to substantially improve the curb's ability to redirect an errant vehicle hitting a curb at a shallow angle, up to a normal speed of 4.7 km/h.
Item Metadata
Title |
Redirection effectiveness of roadside curbs
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Creator | |
Publisher |
University of British Columbia
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Date Issued |
1997
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Description |
Curbs are commonly used along urban streets, in channelised intersections, and along
medians and ramps. One of its purposes is to protect pedestrians. The protection offered
by a curb is measured by its ability to redirect errant vehicles. A curb redirection
effectiveness depends upon the speed and the angle of impact of a vehicle, the height of
the curb, the vehicle mass, and the tire radius. The effectiveness is also influenced by
other factors such as the coefficient of friction between the tire and the curb, the tire
pressure, and the geometric design of the curb.
The redirection ability of a 152 mm high curb of type C design from the AASHTO
Manual was investigated during 28 full scale tests. Six vehicles, of a mass between 675
and 1750 kg, impacted the curb at a speed varying from 6 to 34 km/h, at angles of 5°, 10°,
or 15°. Four tests were performed to evaluate scrubbing conditions and a 90° impact.
Mass was added to some vehicles to measure the influence of the mass without modifying
vehicle dimension and properties.
It was found that a type C curb does not provide an appropriate protection to pedestrians
since it can easily be crossed when the component of the velocity normal to the curb
exceeds 2 km/h. Redirection was not achieved in any of the tests performed at an impact
angle of 15°. According to the tested data, the probability that a vehicle is not redirected
by the curb starts at an impact speed of 10 km/h and reaches 100% at a speed of 40 km/h
when approaching the curb at a 5° angle.
An equation relating redirection speed to the impact angle, the curb height, and the
studied vehicle parameters, was validated. A safe curb height of 205 mm is suggested to
substantially improve the curb's ability to redirect an errant vehicle hitting a curb at a
shallow angle, up to a normal speed of 4.7 km/h.
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Extent |
10019127 bytes
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Genre | |
Type | |
File Format |
application/pdf
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Language |
eng
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Date Available |
2009-03-25
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Provider |
Vancouver : University of British Columbia Library
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Rights |
For non-commercial purposes only, such as research, private study and education. Additional conditions apply, see Terms of Use https://open.library.ubc.ca/terms_of_use.
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DOI |
10.14288/1.0050295
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URI | |
Degree | |
Program | |
Affiliation | |
Degree Grantor |
University of British Columbia
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Graduation Date |
1997-11
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Campus | |
Scholarly Level |
Graduate
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Aggregated Source Repository |
DSpace
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Item Media
Item Citations and Data
Rights
For non-commercial purposes only, such as research, private study and education. Additional conditions apply, see Terms of Use https://open.library.ubc.ca/terms_of_use.