Which Streets are Complete? Mapping Pedestrian, Transit, and Cycling Infrastructure at Scale in San Francisco, CA
Notice bibliographique
Résumé
Contemporary American streets are dominated by the automobile, both its movement and storage, which took root in the early 20th century and has been supported by transportation planners in the decades since. Pedestrian fatalities remain stubbornly high – even in cities with “Vision Zero” goals – and cars generate significant levels of both local air pollution and globally-relevant greenhouse gasses. Moreover, the default use of curbside lanes as on-street parking precludes a number of other street designs, such as wider sidewalks, protected bike lanes, transit bulbs and islands, parklets, rain gardens, and street trees. This dissertation probes these long-standing and consequential street layouts with methods that are both highly granular (accurate to the block level), and at the same time, comprehensive to an entire municipality. San Francisco, California, a dense, high-income, and nominally “progressive” American city serves as the case for three separate analyses: an in-person census of roughly 3,000 municipal bus stops, and review of satellite-imagery of nearly 6,400 intersections for the presence or absence of marked crosswalks, and the provision of on-street parking and its obstruction of a growing bike-lane network. Chapter 1 demonstrates that crosswalk provision varies dramatically across San Francisco, from Census tracts with 100% of intersections exhibiting marked crosswalks, to others with less than 10% coverage. Chapter 2 entails the largest bus-stop census of its kind, covering the entire SFMTA system. This approach finds that one third of all bus stops are blocked by on-street parking, and two thirds lack seating of any kind, as well as spatial clusters of stop amenities. Indeed, both high-quality bus stops and marked crosswalks are present to a far greater extent in the city’s northern half, unexplained fully by transit service, density, or pedestrian volumes. Lastly, Chapter 3 identifies fifty miles of angled parking in San Francisco, a format that roughly doubles on-street parking capacity, and decreases the opportunity for high-quality bicycle lanes. These studies provide both salient datasets to guide San Francisco’s street improvements (of which some progress at City Hall has already occurred), and serve as proof of concepts for planners and researchers elsewhere to probe their own blocks granularly and at scale. Indeed, this dissertation demonstrates new frontiers in applied urban analytics, and broadens and challenges the academic literature on transportation equity. It does so by expanding the types of street elements to be spatialized across neighborhoods, and demonstrates how the provision of seemingly-mundane features such as bus stops, crosswalks, and on-street parking can mirror (and exacerbate) other long-running investment disparities.
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Comment cette classification a été obtenuedéplier
Prédiction machine sur la base complète
Imitation des enseignantsNi prévalence calibrée, ni vérité terrain. Validation humaine à venir. Le volet Gemma est une étiquette directe du modèle pour chaque travail de la base, lue sur la notice réduite au titre. Le volet Codex est un classifieur appris des 10 348 étiquettes directes de Codex et calibré sur les taux pondérés de l'échantillon; les champs sans appui suffisant ne portent aucun appel Codex. Le mode candidate est l'union des deux volets; le consensus est leur intersection. Ces sorties portent le statut machine_predicted_unvalidated et ne sont pas des étiquettes humaines.
Scores du classifieur distillé par catégorie (deux têtes)
| Catégorie | Codex | Gemma |
|---|---|---|
| Métarecherche | 0,000 | 0,001 |
| Méta-épidémiologie (sens strict) | 0,000 | 0,000 |
| Méta-épidémiologie (sens large) | 0,000 | 0,000 |
| Bibliométrie | 0,003 | 0,003 |
| Études des sciences et des technologies | 0,001 | 0,000 |
| Communication savante | 0,001 | 0,001 |
| Science ouverte | 0,000 | 0,001 |
| Intégrité de la recherche | 0,000 | 0,000 |
| Charge utile insuffisante (le modèle a refusé de juger) | 0,002 | 0,000 |
Scores machine (provisoires)
Les deux têtes enseignantes du modèle étudiant, lues sur ce travail. Un score ordonne la base pour la relecture; il n'affirme jamais une catégorie, et le statut de validation accompagne chaque rangée tel quel.
Scores de référence d'un modèle non mature (critères de maturité non atteints, 7 itérations). Un score ordonne; il n'affirme jamais une catégorie.
score_only:v0-immature-baseline · tel quel depuis la passe de notation : score_only signifie que le nombre peut ordonner les travaux, et qu'aucune étiquette de catégorie n'en découleClassification
machine, non validéePrédiction automatique; un appel candidat d’une seule source (Gemma direct ou Codex distillé), pas un consensus.
Le détail, modèle par modèle et score par score, se trouve en fin de page sous « Comment cette classification a été obtenue ».