Ontario Ministry of Transportation

About: Ontario Ministry of Transportation is a government organization based out in Toronto, Ontario, Canada. It is known for research contribution in the topics: Poison control & Asphalt. The organization has 4652 authors who have published 3882 publications receiving 59011 citations.

High-resolution mapping of vehicle emissions of atmospheric pollutants based on large-scale, real-world traffic datasets

Abstract: . On-road vehicle emissions are a major contributor to elevated air pollution levels in populous metropolitan areas. We developed a link-level emissions inventory of vehicular pollutants, called EMBEV-Link (Link-level Emission factor Model for the BEijing Vehicle fleet), based on multiple datasets extracted from the extensive road traffic monitoring network that covers the entire municipality of Beijing, China (16 400 km 2 ). We employed the EMBEV-Link model under various traffic scenarios to capture the significant variability in vehicle emissions, temporally and spatially, due to the real-world traffic dynamics and the traffic restrictions implemented by the local government. The results revealed high carbon monoxide (CO) and total hydrocarbon (THC) emissions in the urban area (i.e., within the Fifth Ring Road) and during rush hours, both associated with the passenger vehicle traffic. By contrast, considerable fractions of nitrogen oxides ( NOx ), fine particulate matter (PM 2.5 ) and black carbon (BC) emissions were present beyond the urban area, as heavy-duty trucks (HDTs) were not allowed to drive through the urban area during daytime. The EMBEV-Link model indicates that nonlocal HDTs could account for 29 % and 38 % of estimated total on-road emissions of NOx and PM 2.5 , which were ignored in previous conventional emission inventories. We further combined the EMBEV-Link emission inventory and a computationally efficient dispersion model, RapidAir®, to simulate vehicular NOx concentrations at fine resolutions (10 m × 10 m in the entire municipality and 1 m × 1 m in the hotspots). The simulated results indicated a close agreement with ground observations and captured sharp concentration gradients from line sources to ambient areas. During the nighttime when the HDT traffic restrictions are lifted, HDTs could be responsible for approximately 10 µ g m −3 of NOx in the urban area. The uncertainties of conventional top-down allocation methods, which were widely used to enhance the spatial resolution of vehicle emissions, are also discussed by comparison with the EMBEV-Link emission inventory.

A Subjective Scale of Speed when Driving a Motor Vehicle

Abstract: An experiment is described which attempts to establish a subjective scale of speed, or more precisely of passive locomotion, such as that experienced by the driver of a motor vehicle. By a method in which the subject is required to produce a speed which in his opinion bears a given proportional relation to the standard speed presented, speed expressed as a sensation Φ and real speed S are tested for a possible power law relation of the form Φ = KSn. It is found that n is not a constant, but has a definite correlation with speed. The time taken by subjects to change from one speed to another is also positively correlated with speed. The implications of these facts are discussed. A more suitable mathematical model is derived from the transformed data from which it is possible to predict performance for sensation ratios other than those tested. Some possible applications of the findings to the study of driver behaviour, and their relevance to speeding offences and accident rate at the ends of motorways, are ...

Environmental monitoring of hydrophobic organic contaminants: the case of mussels versus semipermeable membrane devices.

Abstract: Concentrations of hydrophobic chemicals in mussels and semipermeable membrane devices (SPMDs) from nine studies published over the past decade, amended with new data obtained in the Scheldt−North Sea area, were assessed to understand the similarities and differences between these sampling matrixes. A model was developed to describe the concentration ratios, using literature values of elimination rate constants and steady-state accumulation factors of both samplers as key parameters. The model could successfully describe the results of seven studies. Differences in concentration ratios among these studies were related to the variability of mussel bioaccumulation factors (BAFs) and water sampling rates of SPMDs. For two studies, the model could only describe the data by adopting unrealistically high water sampling rates, and for one study there were not enough data to test the model. We argue that SPMDs will generally yield more reliable estimates of exposure concentrations than mussels, because in situ BAF...