I agree with Gord on the issue of the placement of sharrows on
Grovesenor, but disagree about the design of the traffic calming
I measured the location of the sharrows for west bound traffic last
Sunday, and found that they were centered just 10ft (3m) from the
curb. Given that a typical car door will open to 9 1/2 feet, a
cyclist traveling in the center of the sharrow (which is the intuitive
and intended positioning of cyclists) would be cycling within the door
zone, which defeats the purpose of the sharrow. The lane widths along
this section of road are 2.4m (8ft) for parking, plus 4.3m (14ft) for
each of the travel lanes. So far, so good. The Transportation
Association of Canada recommends a minimum distance of 3.4m from curb
to the center of the sharrow marking when they are painted next to
parked cars. Clearly, that is not the case here. I sent an email to
Kevin Nixon and Ruth Marr pointing out this discrepency on Sunday. I
have not yet heard back. Presumably this can be fixed.
Regarding the traffic circles, Gord is right that the geometry will
force cyclists to merge into the travel lane prior to the traffic
circle, with bicycles and cars traveling single file through the
traffic circle. In the CROW manual I have, the recommended best
practice for bike lanes entering roundabouts (and presumably traffic
circles) is to drop the bike lane and merge cyclists into the travel
lane. Although this seems counter intuitive, it does make sense.
Anyone approaching a traffic circle must scan for vehicles already in
the traffic circle and give way to any vehicles that are present.
That means drivers will be focused on traffic from their left as they
enter the traffic circle. I think asking them to merge to the right
as they come up to a traffic circle would have led to drivers cutting
off cyclists. Similarly, I think that if the bike lane extended up to
the traffic circle, cyclists would have been tempted to ignore the
traffic circle and follow the straight line through without yielding
to traffic already in the traffic circle. The one complaint I may
have with the design is that the dashed line leading up to the traffic
circles does not begin early enough (although I have not measured
it). I would like to see the dashed line start 10m in front of the
traffic circles to give a reasonable amount of space to complete this
This need to merge in and out of the traffic lane is a bit of a catch
22. The traffic circles slow down traffic, which is good, and having
cyclists merge in and out heightens awareness of our presence. The
downside is that some cyclists might not be very comfortable doing
that. One area where the city definitely failed was in public
education over how to use the new traffic circles. We asked for and
received assurances there would be an educational component to the new
infrastructure, but obviously that never came through. I guess it
will be up to us to provide that education.
On Oct 15, 4:13 pm, David Wieser <davidwie...@gmail.com
> I agree with everything Gord said. I do like that there are the traffic calming circles instead of stop signs. They could just be designed better for cyclists.
> Sent from my iPhone
> On 2010-10-15, at 4:09 PM, Gord McGonigal <gord.mcgoni...@gmail.com
> > Add me to the list of people that currently don't understand the
> > treatment on Grosvenor.
> > West of Cambridge, at the traffic circles every couple of blocks, the
> > bike lane ends and bikes must merge with cars before going through the
> > circle. The geometry further implies that cyclists must yield to
> > overtaking motorists (as it is clearly the bike lane that ends). I am
> > not sure how this is an improvement for me. I suppose it is nice I may
> > not have to stop at a 4-way stop, but the constant need to merge I
> > found to be quite annoying (even in light traffic). And for
> > inexperienced cyclists it seems downright dangerous if they have to
> > merge with cars every several blocks!
> > East of Grosvenor it is not as bad, but I think there are still
> > problems. The sharrows are not placed far enough away from the parked
> > cars. It makes no sense that the safest line for a bicycle should be
> > along the edge of the sharrow and not the middle.
> > Gord
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