Ian Swain wrote the following note recently, and I thought this topic deserved a thread of its own.

Dear Steve:

Something in the Star’s article on Cherry Street last week made me curious. Here’s the relevant quotation (emphasis added):

But the Cherry St. configuration isn’t likely to replace the traditional centre-road streetcar pattern. For one thing, it requires building truck access in behind the buildings on the transit side of the street, something that couldn’t be retrofitted into most existing neighbourhoods.

There’s also the challenge of right turn signals. The transitway envisioned for this section of Cherry would be only 800 to 900 metres long, or about three stops. To build it any longer would slow down streetcars because they would have to constantly pause to make way for turning motorists, Dawson said. 

Do you think the superintendent of TTC route planning is correct that a streetcar right-of-way on one side of the street is inevitably slowed by right-turning cars? Or is it just reluctance on the part of the city to slow right-turning cars a bit with better transit priority?

Thanks,
Ian

First, let’s put Cherry Street in context.  The eastern waterfront is a blank slate for new development and street design allowing us to think about the way building access is provided.  On Cherry itself, the situation is special when compared to proposed new Transit City lines.  The existing street grid contains short blocks and the desire is for for a strong pedestrian presence.  Placing the streetcar right-of-way on the east side of Cherry makes the space an extension of the car-free eastern sidewalk. 

The short blocks would be a problem, as they are everywhere, regardless of where the right-of-way is located.  Views of the proposed layout are in the TTC report starting at page 15.

Current signal priority arrangements look one block ahead and deal with nearside stops.  A good example is on King between Sherbourne and Jarvis where a traffic signal was added at George Street.  Although there is no stop here, George is close enough to the nearby signals that there is not enough time between the point where an approaching car is detected and the cross street for the signal reliably provide a green phase for transit.

Sherbourne and Jarvis Streets are also close to George, but they have transit stops where the car will almost always wait, and this gives the signals more time to cycle.  The proposed design for Cherry uses nearside stops at Front Street and this has the advantage of giving the signals time in which they can clear for the streetcars.

On Queen’s Quay West (the existing Harbourfront Line), the stops are farside and this arrangement almost guarantees a red light for the streetcar because the distance (and hence time lag) between detection and arrival at the signal is shorter than needed to cycle the signal in the streetcar’s favour.  This can be seen for cars approaching Lower Simcoe (the Harbourfront Centre stop between John and York) where detection occurs after cars leave a farside stop with a short run to the next signal.

The problem with closely spaced intersections and signals applies throughout the old streetcar network especially as many existing pedestrian crosswalks are converting to full traffic lights.  Some way is needed for transit operators to request priority far enough in advance that signals can be cleared by the time their vehicles arrive.  Although it is possible, indeed common, to link the cycle of minor intersections to nearby major signals, problems arise in providing this on a bi-directional basis.  Moreover, signal timings are always optimized for road traffic flow overall, not for transit vehicles that stop periodically for passengers.  Definitely, we need a more sophisticated method of requesting transit priority than simply being within “x” metres of an intersection.

The issue with right turns for overall street design is not the signals per se, but the need for road traffic to use driveways entering properties on the east side of Cherry.  These conflicts can be eliminated by suitable layout placing the delivery access behind buildings in laneways rather than on the main street.  However, when we come to existing arterials such as Eglinton, Sheppard or Finch, the driveways are already in place and we don’t have the option of closing most of them off with an LRT right-of-way.  This dictates a centre-of-road alignment bringing its own problem of eliminated left turn lanes and access.

Cherry must also be seen in the larger context of plans for Queen’s Quay itself.  The Dutoit Allsopp Hillier site includes a number of views of this proposal.  Queen’s Quay will change from a central right-of-way to side-running by virtue of the closure of the existing eastbound traffic lanes.  Properties on the south side of Queen’s Quay have relatively few access points for cars, but some of them are not at locations where a right-of-way crossing already exists.  This is definitely a challenge for the designers today and for the TTC’s operations once the changes are implemented.

Fortunately, much of Queen’s Quay East remains to be developed and it may be possible to co-ordinate a side-running right-of-way for the East Bayfront portion of the line and continue the Cherry Street layout to the west.  A major debate, still in progress, concerns the section from east of Yonge to west of Bay.  There is a strong desire by local community groups to bring the streetcars back onto the surface somewhere on Bay Street so that the existing ramp west of Bay can be eliminated and no ramp will be required to the east.  Access to the Harbour Castle Hotel is a challenge from a traffic point of view, but the primary desire is to make a better pedestrian zone around the Bay Street intersection including pedestrian flows between transit and the Ferry Docks.

Moving the portal for the streetcar tunnel onto Bay Street (ironically where it was originally intended to be) runs into problems with the close street grid and the steep grade needed to fit a ramp between any pair of streets.  The design of Queen’s Quay from York to east of Yonge will be strongly affected by whatever is technically feasible and acceptable for its impacts on traffic, pedestrians and transit.

The Waterfront shows in microcosm the difficulties faced by integrating a major change of street space use into an existing community.  In some places, we have the comparative luxury of designing from scratch, but this doesn’t eliminate all problems.

Transit City designs face the arduous task of fitting into streets that are overwhelmingly auto-oriented.  One goal of the Official Plan is redevelopment to eliminate parking abutting the sidewalks so that these will become pedestrian-friendly areas.  This is more than an exercise in plunking a streetcar line down the middle of a road, and the right-of-way treatments need to complement the redevelopment that will come.