afransen
Senior Member
Roundabouts explicitly work with continuous flows. Traffic lights require platoons to work efficiently. So it is best not to mix them, or you get surges of traffic causing delays at roundabouts.
Since everyone has to slow down and possibly stop before entering the roundabout, I can foresee traffic being backed up from one roundabout to the next in rush hour unless the roundabout is 4 lanes wide. Eglinton is just too busy for a string of roundabouts. This is probably better suited for Rathburn, Burnhamthorpe or Royal York.Roundabouts explicitly work with continuous flows. Traffic lights require platoons to work efficiently. So it is best not to mix them, or you get surges of traffic causing delays at roundabouts.
A reason to wear masks on any underground railway?Here’s one more good reason to wear a mask on the T: new scientific research has discovered unhealthy levels of air pollution on subway platforms in Boston and New York City.
During the summer of 2019, researchers from the NYU Grossman School of Medicine measured air samples in 71 stations during the morning and evening rush hours in Boston, New York City, Philadelphia, and Washington, D.C. Their findings were published on Wednesday in the journal Environmental Health Perspectives.
While New York’s subway stations had the dirtiest air, the study team found that the concentration of airborne pollutants on underground train platforms in Boston still reached levels that raise concerns for riders and for transit employees who spend long periods of their day underground.
The study team found that the average level of fine particulate pollution on Boston’s underground subway platforms was 139.8 micrograms per cubic meter – a level of pollution that’s categorized as “unhealthy” under the EPA’s air quality index.
Air quality measurements at above-ground stations, on the other hand, were found to be comparable to the ambient levels of air pollution on surrounding streets.
“Our findings add to evidence that subways expose millions of commuters and transit employees to air pollutants at levels known to pose serious health risks over time,” said the study’s lead author David Luglio, a doctoral student at NYU Grossman, in a press statement accompanying the research paper.
Among the MBTA stations that were analyzed, the study team found the dirtiest air samples on the Broadway station on the Red Line. More detailed analysis found that the primary source of pollution seems to be iron dust generated from train wheels and rails, as well as from wear and tear from trains’ collector shoes that brush against the third rail. Dust from decaying organic matter was another major component of underground pollution.
Notably, the study only measured air quality on the rapid transit network, not on commuter rail platforms, where diesel exhaust from trains could generate even higher levels of hazardous pollution.
The authors plan to do additional research into why some subway systems, like Philadelphia’s, are less polluted than others, and to recommend practices that could improve air quality in stations relatively quickly.
The MTBA is in the midst of a major project to upgrade ventilation and improve air quality at the Back Bay station, where passengers can often smell the exhaust from diesel commuter rail trains. Streetsblog has reached out to the agency to comment on this research; this story will be updated if and when they respond.
The Montreal Metro is actually better for brake dust because they use wood brakes.Apparently something similar was found on the London Tube platforms by some YouTubers with a PM2.5 detector. TfL apparently responded that subways use friction brakes which causes the high PM2.5, but that they were looking at using regenerative braking. Why had they not already done so! The maintenance savings alone are significant, never mind the health impacts. I would also expect rubber tire metro to be worse for PM2.5.
But its all-underground and with less than optimal ventilation.The Montreal Metro is actually better for brake dust because they use wood brakes.
The worse PM 2.5 is from tire particles.The Montreal Metro is actually better for brake dust because they use wood brakes.
The worse PM 2.5 is from tire particles.
It's actually a real problem. A lot of PM2.5 will remain in cities even after EVs are adopted just from tire wear. It's just that currently, diesel engines, car exhaust and brake dust swamp the contributions from tire wear.
Overall, PM2.5 levels were found to be highest in the Toronto metro, a system that is largely below-grade and using a traditional steel wheel-steel rail rolling stock design. Steel wheel-steel rail metro design has been noted to generate PM “rail dust”.(5, 19-23) This environment is also subject to the regular resuspension of particles due to the piston effect of train movement. The piston effect has been suggested by the examination of temporal variability in metro PM levels which coincide with a sharp rise in wind speed/turbulence and the motion of a train.(21, 24) Montreal is also a below-grade system, but the much lower sampled PM2.5 levels may be due to the use of rubber wheels and concrete rollways compared to a conventional steel wheel-steel rail design. 21% of daily PM2.5 exposure in Toronto, 11% in Montreal, and 12% in Vancouver.
No. It's not even a Phase 3, in that there's no alignment chosen etc. It's aspirational, and the former GTAA CEO was the one really pushing for it; not sure if the current one sees it as a priority.Is there enough funding to continue the line to Pearson, or is that a phase 3?
I believe that the hope was that the GTAA would be contributing funding to complete the connection between the LRT and Pearson (along with their whole 'Union West' transit hub concept), but COVID has really destroyed their financial situation and I don't see it happening any time soon now.Is there enough funding to continue the line to Pearson, or is that a phase 3?
Why not extend the line directly to Terminals 1 and 3 instead? The stations do not have to be too massive. plus you have direct access to both terminals, unlike the previous Union Station West concept.I believe that the hope was that the GTAA would be contributing funding to complete the connection between the LRT and Pearson (along with their whole 'Union West' transit hub concept), but COVID has really destroyed their financial situation and I don't see it happening any time soon now.