Estimation of free-flow speed

Estimation of free-flow speed

In 2010 Highway Capacity Manual, one preferably determines free-flow speed by deriving it from a speed study involving the existing facility or on a comparable facility if the facility is in the planning stage. Many have used a ‘rule of thumb’ by adding 10 km/h (5 mi/h) above the posted limit to obt...

Full description

Saved in:
Bibliographic Details
Published in:KSCE journal of civil engineering Vol. 18; no. 2; pp. 646 - 650
Main Authors: Fazio, Joseph, Wiesner, Brady N., Deardoff, Matthew D.
Format: Journal Article
Language:English
Published: Berlin/Heidelberg Springer Berlin Heidelberg 01-03-2014
Springer Nature B.V
대한토목학회
Subjects:
Civil Engineering
Coefficients
Correlation
Correlation coefficient
Correlation coefficients
Engineering
Freeways
Gaussian distribution
Geotechnical Engineering & Applied Earth Sciences
Goodness of fit
Highways
Industrial Pollution Prevention
Manuals
Mathematical models
Normal distribution
Radar
Roads & highways
Speed limits
Statistical tests
Streets
Transportation Engineering
토목공학
limit
sign
free-flow
speed
posted
traffic
Online Access:Get full text
Tags: Add Tag
No Tags, Be the first to tag this record!
Description
Summary:In 2010 Highway Capacity Manual, one preferably determines free-flow speed by deriving it from a speed study involving the existing facility or on a comparable facility if the facility is in the planning stage. Many have used a ‘rule of thumb’ by adding 10 km/h (5 mi/h) above the posted limit to obtain free-flow speed without justification. Two team members using a radar gun and manual tally sheets collected 1668 speed observations at ten sites during several weeks. Each site had a unique posted speed limit sign ranging from 30 km/h (20 mi/h) to 120 km/h (75 mi/h). Five sites were on urban streets. Three sites were on multilane highways, and two on freeways. Goodness-of-fit test results revealed that a Gaussian distribution generally fit the speed distributions at each site at a 5% level of significance. The best-fit model had a correlation coefficient of +0.99. The posted speed limit variable was significant at 5% level of significance. Examining data by highway type revealed that average free-flow speeds are strongly associated with posted speed limits with correlation coefficients of +0.99, +1.00, and +1.00 for urban streets, multilane highways, and freeways, respectively.
Bibliography:ObjectType-Article-1
SourceType-Scholarly Journals-1
ObjectType-Feature-2
content type line 23
G704-000839.2014.18.2.030
ISSN:1226-7988
1976-3808
DOI:10.1007/s12205-014-0481-7