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Bike Lanes: Pros & Cons
Research supporting
the safety of bike lanes
Opposed to bike
lanes
Related
ideas
- "Sharrows" are "shared-lane arrows" painted onto the
street to show motorists and cyclists that they're
supposed to share the lane. They're being promoted as an
alternative to bike lanes, especially on roadways where
there isn't enough space for a dedicated bike lane. Alta
Planning conducted a
detailed study of sharrows in 2004.
Pros and Cons of Bike
Lanes
by Mike
Dahmus, April 2, 2005
There are no good studies proving that bike lanes or wide
curb lanes are better than the other. ALL theories you hear
on which one is better are resting on somebody's opinion.
[Update, Feb. 2007: A few months ago, a
study did come out which claimed to show a non-trivial
safety enhancement for marked bike lanes vs. wide curb
lanes.]
I'm one of the people who thinks we overprescribe bike
lanes, but it bugs me that so many Forsterites are so
hostile to them in general. Both bike lanes and wide curb
lanes have their place.
I'm operating under the assumption that we're comparing
bike lanes to wide curb lanes; not narrow curb lanes. The
theory that we can reengineer the 98% of Austin that needs
it to a grid pattern like Hyde Park where we don't need
EITHER facility is just ludicrous.
My general feeling on when bike lanes are
appropriate:
- Where there are lots of inexperienced bicyclists
- Where speed differential is fairly high
- Where volume of bicyclists is very high
My general feeling on when wide curb lanes are
appropriate:
- Where speed differential is lower
- Where bicycle volume (all types) is moderate to
low
Where not to put bike lanes:
- Low-speed or congested roadways where turning volume
is very high
- Residential streets (NOTE: DESPITE NEIGHBORHOOD
MISREPRESENTATIONS, "RESIDENTIAL STREET" IS A CATEGORY OF
ROADWAY SEVERAL LEVELS BELOW SHOAL CREEK BOULEVARD).
- Where they can't be swept or otherwise
maintained
- Where you can't commit to "no parking".
Things I believe that are PROs for bike lanes:
- Bike lanes attract new cyclists; wide curb lanes do
not. I think this is self-evident. Patrick agreed, and so
do most people who actually work in the field (not the
people who commute and criticize; but the people who are
paid to try to increase cycling in their particular
city).
- No amount of education so far has been able to match
up against the bike lane stripe as a way to get people
out on their bikes. Of course, this may be a good thing
if you think we don't need more uneducated cyclists out
there.
- You can't attract new cyclists to a road like
Jollyville without a bike lane stripe. Period. The
automobile traffic moves too fast. A wide curb lane
simply doesn't provide the space that new cyclists think
they need in a way which makes sense to them, coming from
the world of the automobile. (We don't make the
right-hand lane up a hill twice as wide so trucks can
pull to the side; we stripe another lane).
- If you accept riding on shoulders on 360, you should
accept riding in bike lanes on Jollyville. The
argumentative convulsions some Forsterites go through to
defend shoulders from the same logic they use against
bike lanes are breathtaking. (They do this, I think,
because they know that even most Forsterites don't want
to share a lane at 65; the same anti-bike-lane reasoning
with a few exceptions would logically apply to
shoulder-riding).
- Most cyclists for whom bike facilities are built are
not the expert cyclists that you and I might be. They are
instead the novice cyclist that I used to be (and
presumably you used to be).
- Even on low-speed roadways, utility for the
population AS A WHOLE sometimes demands the
channelization of low-speed traffic. For instance,
Speedway and Duval north of UT - car speeds are 25-30;
bike speeds are 10; this isn't normally enough speed
differential to justify separation, but the volumes of
cars and bikes are both high, and the corridor's
thoroughput for both cars AND bikes is thus improved by
partial separation of the modes.
- (this is from the link I gave a few days ago) - it is
possible to have a better average passing distance on a
roadway with a wide curb lane, but still have a better
overall level of safety in passing distance with a bike
lane. Whether this happens in practice is debatable - but
it is a fact that you shouldn't use "average passing
distance" to compare the facilities.
- The idea (stolen from a semi-Forsterite) that we can
easily get roads restriped with wide curb lanes is in
reality not true. If you want space for bikes to be taken
from car lanes, it generally has to be a bike lane. (I
don't know why this is, but it seems to be true, although
Austin has an exception or two here).
CONS for bike lanes
- Car drivers do tend to think you need to stay in the
bike lane (even when obstructed, unsafe, whatever - they
usually can't see the obstruction). Also, car drivers
often think you should only ride on roads that have bike
lanes. This problem exists with wide curb lanes too, by
the way.
- Bike lanes are theoretically more obstructed than
wide curb lanes. I don't believe this to be true, but
most people do, so I'm listing it here. For instance,
Bull Creek doesn't seem any less obstructed north of 45th
where there are wide curb lanes. In Austin, at least,
BOTH facilities need vast amounts of sweeping which
they're just not getting.
- Sometimes cyclists will stay in a bike lane when they
need to leave it due to an obstruction or intersection
approach. This is a sign of bad bike lane design in most
cases and can be overcome, but is hard to get right,
judging from how often it's done wrong.
- Sometimes cyclists will stay in a bike lane when they
should be leaving it to turn (the "turn left out of the
far right lane" phenomenon). The problem here is that I
see this happen on wide curb lanes fairly often as well.
The only solution here is heavy enforcement.
- Bike lanes supposedly encourage wrong-way cycling.
(Whatever happened to painting arrows, by the way?
Jollyville didn't get them...) - again, I see this often
with wide curb lanes too. Heavy enforcement and more
arrows.
Questioning the safety of bicycle
lanes
by Fred Meredith, May 1,
2003
You may FEEL safer, but it may be a false sense of
security. The only thing that is going to actually make you
safer on those streets is how you and the other road users
behave....
If the bike lane is painted to the intersection, are you
going to stay in it if you go straight across the
intersection?
What should the car turning at that intersection do?
Should he/she come over into the bike lane to make the turn?
Do they know that?
Are you going to stay in the bike lane if it is right
next to parked cars [any one of which could open its
door in your path]? If cars are parked on the left side
of a one-way street and there is a bike lane on the left
side, are there special considerations you should keep in
mind?
Why is the bike lane any safer than being out in the
middle of the traffic lane? There are lots of other lanes
for the rest of the road users, why shouldn't you have one?
If you feel unsafe in a traffic lane, then maybe you need
more experience/practice/or something. Maybe less
paranoia.
by Jeffrey Thorne, Jan. 4,
2005
I have to question some of the statements supporting bike
lanes from the research above.
"encourage bicyclists to ride in the correct
direction of travel"
That doesn't match my observations here in Austin.
Judging by the number of riders I see riding the bike lanes
against traffic flow, I'd say they encourage that
behavior instead. I don't see much riding against traffic
except in bike lanes. I have to wonder about the "national
study" concluding otherwise. According to Jeffrey Hiles'
Listening to Bike Lanes (see below), more cyclists
ride the wrong way on streets with bike lanes than on those
without.
"signal motorists that cyclists have a right
to the road"
That is, they signal that bikes belong in bike lanes,
which some would take to mean ONLY in bike lanes, which is a
false message for motorists and cyclists alike.
"remind motorists to look for cyclists when
turning"
In my experience and in the conclusions of several
studies, bike lanes may actually increase the incidence of
motorists hitting cyclists while turning in front of them.
This seems to be because the motorist who normally would
turn right from the right edge of the road, not cutting off
the cyclist's path (the cyclist would be behind or in front
of the turning car), is encouraged by the bike lane stripe
to make the turn from a farther left position, cutting off
the cyclist's path.
I do support bike lanes as a tool for solving traffic
problems where problems are occurring. Usually, I see bike
lanes being established where riding was safe and enjoyable
already, and in those places they are at best a waste of
paint and at worst creating dangers that weren't present
before.
from Jeffrey Hiles'
Listening
to Bike Lanes
Studies of bicyclists' behavior point to one overriding
rule: The more options cyclists have, the more options they
take. This is true whether or not those options are
officially sanctioned.
The side of the street on which bicyclists ride, for
example, is influenced by the kind of space they have in
which to ride. Thom and Clayton (1992a) observed bicyclists
riding at mostly busy intersections with standard 12-foot
lanes and speed limits mostly either 50 or 60 kph (31 or 37
mph). A full 97.6 percent of the cyclists rode on the side
of the street with the flow of traffic (p. 97). On most of
the streets at the seven intersections studied, bicyclists
would have had to ride close to on-coming traffic if they
had chosen the other side of the street.
The picture changes where bicyclists have more room. A
study of bicyclists on nine streets with striped bike lanes
(Cycecki, Perry, & Frangos, 1993) found that 22 percent
of the cyclists who rode on the streets chose to ride facing
the motor traffic on their side of the street. On one street
the bike lane was marked with four arrows per mile "to show
clearly that bicyclists must ride with traffic." Apparently
the arrows did not deter wrong-way riding as much as the
extra space encouraged it; 23 percent still rode facing
traffic. On another bike-laned street, 39 percent cycled
against the flow (pp. 29, 31).
from Tom Wald, Feb. 12,
2007
If you've biked on west 29th St between Rio Grande and
Shoal Crest (between Guadalupe St and Lamar Blvd), you
probably recognize a case where the painting of bike lanes
is highly questionable.
On this stretch of road, from the center line to the curb
is about 14 feet. (Not so incidentally, 14 feet is the
maximum lane width for which Texas State Law *explicitly*
allows a bicyclist to use the entire lane). However, there
are currently bike lanes marked on this stretch of road.
These bike lanes measure about two to four feet wide, if my
spatial memory is correct.
My impression is that some motorists get fairly
frustrated when I ride outside of the marked bike lane on
this road, as is evidenced by their aggressive driving,
creating unsafe situations for all involved, and horn
signals. I don't really fit inside the bike lane -- in some
places, I think any of my bikes are too wide for the
lane.
Of the three choices -- bike lane, sharrows, and no
markings -- having marked bike lanes easily takes last
place. If sharrows were used, I'd like to see them centered
somewhere between 40-50% from the center line so that
motorists don't get any impression that it's reasonable to
pass. Perhaps though, in 2007, no markings is the best
choice.
Supporting Bike Lanes
Mike
Dahmus, Mar. 30,
2005
Most of the people who argue that bike lanes are almost
always bad tend to be in one of these groups (or
combinations thereof):
1. focused with laser-sharp precision on the needs of
current (experienced) transportational cyclists (i.e. don't
think or care about kids, novices, elderly) - tend to be
people who live in areas where cycling just tends to happen
by itself and doesn't need promotion or encouragement.
2. inexperienced with suburban cycling conditions (i.e.
why would you ever need a bike lane or marked shoulder if
roads are laid out in a grid pattern with design speeds of
30 mph) - tend to be disproportionately European, some
Amercan adherents among Forsterites mainly in the northeast
or midwest United States - areas which haven't seen much
growth since the 1960s or so. IE - these are people who
never have to ride on roads like Jollyville to get where
they want to go.
3. careless about the needs of the city to ensure good
traffic flow for all users of a corridor - i.e. sometimes
the bike lane exists to increase the likelihood that
motorists can maintain some reasonable level of speed, and
this isn't necessarily a bad thing. IE, these are people who
think the city shouldn't care that automobile traffic would
often and suddenly be restricted to 10 mph or so on any
given street since some motorists don't effectively know how
to pass cyclists without the help of a stripe.
They also tend to neglect statistical thinking in their
arguments - focusing, for instance, on the average passing
distance they get from motorists in wide curb lanes vs bike
lanes, rather than looking deeper to the 10th percentile
case. (more
details).
Those of us in the real world note that many Shoal Creek
corridor users are very young or very old, and that it tends
to attract novice cyclists of all ages (me, for instance).
It, while theoretically a low-speed corridor, has an
apparent design speed of 40 mph or so, and serves as a
transportation spine which can be an alternate for Burnet
Road and Mopac for cyclists (improving conditions for
cyclists and drivers if it succeeds in attracting most
cyclists away from those two corridors). It also functions
as a minor arterial itself (even though bogusly reclassified
as a collector) and thus needs to worry about flow of cars
in addition to bikes.
Another site by Michael Bluejay... |
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