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Record W2197202973 · doi:10.3141/2483-02

Relationship of Lane Width to Capacity for Urban Expressways

2015· article· en· W2197202973 on OpenAlexaff
Jian Sun, Jianhao Yang

Bibliographic record

VenueTransportation Research Record Journal of the Transportation Research Board · 2015
Typearticle
Languageen
FieldEngineering
TopicTraffic control and management
Canadian institutionsMinistry of Education and Child Care
Fundersnot available
KeywordsTransport engineeringFlexibility (engineering)Traffic flow (computer networking)Variance (accounting)Highway Capacity ManualEnvironmental scienceStatisticsComputer scienceMathematicsEngineeringBusinessLevel of service

Abstract

fetched live from OpenAlex

To increase the capacity of urban expressways in Shanghai, China, additional lanes were created during the past decade through reconstruction. Field measurements indicate that maximum lane width is 3.97 m and minimum width is only 2.73 m. To investigate the relationship between lane width and capacity for urban expressways, 3 months of traffic flow data were extracted and filtered from the system to manage inductive detectors on Shanghai's urban expressways. Analysis of all 440 segments of expressways in Shanghai showed that only 60 sites could reach their capacity; the characteristics of these 60 sites were further analyzed statistically. An analysis of a variance, a regression analysis, and a t-test were used to explore the relationship between lane width and capacity. The research showed that lane width had no statistically significant effect on capacity. Two causes that might account for this finding are discussed further: (a) free-flow speeds are similar for different lane widths according to the findings of a t-test that found no statistically significant differences and (b) the critical speed when capacity is reached for a Shanghai expressway is very low, only 45 km/h. Thus, drivers can deal with a narrow lane width at such a low critical speed. This finding suggests that geometric design policies for capacity purposes should provide substantial flexibility for use of narrower lane widths on urban expressways with low speed limits, although those lane widths must be subject to safety considerations.

Fetched live from OpenAlex and de-inverted. Abstracts are not stored in this database: the inverted indexes are 8.6 GB of the frame’s 9.3 GB of text, and the host has 13 GB free.

How this classification was reachedexpand

Full frame distilled prediction

Teacher imitation

Not calibrated prevalence, not ground truth. Human validation pending. Learned from the 10,348 direct Codex labels and 10,348 direct Gemma labels. Candidate is the union of thresholded teacher heads; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels or direct frontier model labels.

metaresearch head score (Codex)0.004
metaresearch head score (Gemma)0.000
Version: codex-gemma-dda1882f352aValidation status: machine_predicted_unvalidated
Candidate categoriesnone
Consensus categoriesnone
DomainCandidate signal: none · Consensus signal: none
Study designCandidate signal: Observational · Consensus signal: Observational
GenreCandidate signal: Empirical · Consensus signal: Empirical
Teacher disagreement score0.511
Threshold uncertainty score0.600

Codex and Gemma teacher scores by category

CategoryCodexGemma
Metaresearch0.0040.000
Meta-epidemiology (narrow)0.0000.000
Meta-epidemiology (broad)0.0000.000
Bibliometrics0.0010.001
Science and technology studies0.0000.000
Scholarly communication0.0000.000
Open science0.0010.000
Research integrity0.0000.001
Insufficient payload (model declined to judge)0.0000.000

Machine scores (provisional)

The two teacher heads of the student model, read on this work. A score orders the frame for review; it never asserts a category, and the validation status ships verbatim with every row.

Baseline scores from an immature model (maturity gate not passed, 7 training rounds). Scores rank; they never assert a category.

Opus teacher head0.154
GPT teacher head0.350
Teacher spread0.196 · how far apart the two teachers sit on this one work
Validation statusscore_only:v0-immature-baseline · verbatim from the scoring run: score_only means the number may rank works, and no category label ships from it

Classification

machine, unvalidated

Machine predicted; a candidate call from one teacher head, not a consensus.

The models applied no category: nothing in the taxonomy fit this work.
Study designObservational
Domainnot available
GenreEmpirical

How this classification was reached, model by model and score by score, is at the end of the page under "How this classification was reached".

Quick stats

Citations18
Published2015
Admission routes1
Has abstractyes

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