File(s) under permanent embargo
A Tobit model for analyzing speed limit compliance in work zones
journal contribution
posted on 2014-12-01, 00:00 authored by Ashim DebnathAshim Debnath, R Blackman, N HaworthPoor compliance with speed limits is a serious safety concern in work zones. Most studies of work zone speeds have focused on descriptive analyses and statistical testing without systematically capturing the effects of vehicle and traffic characteristics. Consequently, little is known about how the characteristics of surrounding traffic and platoons influence speeds. This paper develops a Tobit regression technique for innovatively modeling the probability and the magnitude of non-compliance with speed limits at various locations in work zones. Speed data is transformed into two groups-continuous for non-compliant and left-censored for compliant drivers-to model in a Tobit model framework. The modeling technique is illustrated using speed data from three long-term highway work zones in Queensland, Australia. Consistent and plausible model estimates across the three work zones support the appropriateness and validity of the technique. The results show that the probability and magnitude of speeding was higher for leaders of platoons with larger front gaps, during late afternoon and early morning, when traffic volumes were higher, and when higher proportions of surrounding vehicles were non-compliant. Light vehicles and their followers were also more likely to speed than others. Speeding was more common and greater in magnitude upstream than in the activity area, with higher compliance rates close to the end of the activity area and close to stop/slow traffic controllers. The modeling technique and results have great potential to assist in deployment of appropriate countermeasures by better identifying the traffic characteristics associated with speeding and the locations of lower compliance.
History
Journal
Safety scienceVolume
70Pagination
367 - 377Publisher
ElsevierLocation
Amsterdam, The NetherlandsPublisher DOI
ISSN
0925-7535eISSN
1879-1042Language
engPublication classification
C1.1 Refereed article in a scholarly journalCopyright notice
2014, Elsevier Ltd.Usage metrics
Categories
No categories selectedKeywords
Licence
Exports
RefWorks
BibTeX
Ref. manager
Endnote
DataCite
NLM
DC