Incidence of Speed on Risk of Severe Injuries or Fatalities During Collisions on Urban Roads
Bibliographic record
Abstract
All stakeholders seem to agree that speed is one of the main causes of road collisions. Thus road safety experts determine speed limits based on road environment. The present study aims at validating the 50 kph legal speed limit in urban environment in the province of Quebec, Canada, and to quantify the risk to be involved in a collision with fatal or serious injuries when this limit is exceeded. In this study, reconstruction of collisions with fatal or serious injuries on urban roads of the city of Montreal was carried out. The study encompassed 39 collisions which occurred on roads with posted speed limit of 50 kph during the years 2001 and 2002. The selected collisions had to satisfy a number of criterion allowing to eliminate masking effect such as alcohol and illegal maneuver. The majority of cases were fatal collisions while the remaining cases involved life threatening injuries. In order to evaluate the relative risk of being involved in a collision with fatal or serious injuries, the traveling speed of 4 control vehicles was recorded. These vehicles were then traveling at free speed on the same road, under similar weather conditions, and at same time of day as the vehicle case. Fifty kph speed reduction scenarios were applied to the collisions for which the case vehicle speed exceeded the legal limit. This made possible the determination of the effect of excessive speed on collisions with fatal or serious injuries. Results of the study show that if the drivers had followed the 50 kph limit, there would have been a reduction of 44 % in the total number of collisions with a reduction of 83 % of frontal collisions, 33 % of side collisions and 23 % of collisions with pedestrians. The results also show that the relative risk of being involved in a collision with fatal or severe injuries is greatly increased at speeds exceeding the legal limit, with a multiplicative factor of 81 at travelling speeds above 80 km/h. Global data shows quite clearly that the legal speed limitation of 50 kph in an urban environment constitutes a valid reference in terms of collision injury reduction and overall road safety.
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How this classification was reachedexpand
Full frame machine prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. The Gemma side is a direct model label for every work in the frame, read from the title-only record. The Codex side is a classifier learned from the 10,348 direct Codex labels and calibrated to design-weighted sample rates; fields without enough sample support carry no Codex call. Candidate is the union of the two sides; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels.
Distilled classifier scores by category (both heads)
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.000 | 0.002 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.001 | 0.001 |
| Science and technology studies | 0.000 | 0.000 |
| Scholarly communication | 0.000 | 0.000 |
| Open science | 0.000 | 0.000 |
| Research integrity | 0.000 | 0.000 |
| Insufficient payload (model declined to judge) | 0.002 | 0.000 |
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.
score_only:v0-immature-baseline · verbatim from the scoring run: score_only means the number may rank works, and no category label ships from itClassification
machine, unvalidatedMachine predicted; a candidate call from one source (direct Gemma or distilled Codex), not a consensus.
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".