ION - Waterloo Region's Light Rail Transit

[ijmorlan]

The thing about five minute headways is that it starts to get nasty for traffic at crossings. At a five minute headway, there is an average of 2.5 minutes between trains.

I always hear this, even here, and I don't get it.  If we have the ridership to justify a rain every 5 minutes (or every 3 minutes)...that's 250 people per train, then that justifies keeping those crossings down...if it was an intersecting road, with cars on it, we would keep the traffic signals green for far longer to clear the traffic jam...and there wouldn't even be discussion about that, but somehow because it's people on a train, that's a reason to reduce service on the intersecting road?

I have a few comments, but no firm conclusion.

It’s no problem to have one bus per cycle of the traffic lights. I believe this is typically around 2 minutes or so. Even more is possible, but especially if there is a stop at the intersection you can start to have problems. So based on this, there should not be a problem at regular intersections.

On the other hand, crossings work differently and some of them block traffic for much longer than necessary. For example, northbound trains leaving Seagram stop University traffic before the train even leaves. This isn’t so bad, especially since pedestrians can use the time, but it does mean the train takes more time from the crossing than it really needs. Much worse, however, northbound trains leaving the public square stop shut down Erb and Caroline before they even close their doors. On top of that, they’re closing down an intersection: nobody can move (well, in reality pedestrians can do some crossings of the intersection that don’t cross the tracks, but officially they can’t). In effect, it’s really the intersection of 3 routes: two roads and a train line, each of which needs its green time.

Note too that traffic lights go on their own schedule, which can be optimized but isn’t pre-empted by anything except emergency services. One LRT per 2 minutes in each direction could pretty much shut down a railway crossing permanently whereas one LRT per minute arriving at a traffic light in an on-road segment should be OK, just as it is OK for buses (but note the warning above about stopping), because the LRTs in each direction would have to wait and go together when their direction got its green.

The comment about the number of people on a train is very on-point: if the traffic being carried by the train line is similar to that being carried by the crossing street, it’s perfectly reasonable for the train to take half the time, even if that results in the street being backed up. It’s not the fault of the LRT that it’s efficient.

So overall I think that from the point of view of “snarling” (to use the word always used by LRT denialists) traffic, frequencies down to about every 5 minutes should be OK with the system as it is. Going above that would require at a minimum re-timing some of the crossings and possibly re-design of some areas.

Even without such an increase in frequency, it would be prudent to allow Caroline St. traffic to proceed when only the southbound LRT track is in use. There is no conflict between that track and Caroline St. other than turns onto westbound Erb St. At higher frequency however this improvement would be necessary unless road traffic is significantly reduced from how much we have now.