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Lanes vs Wide Outside Lanes
When additional space on collector and arterial roads is deemed beneficial to both
bicyclists (for comfort when motorists are passing) and motorists (for ease of passing)
Bike Lanes (BLs) and Wide Outside Lanes (WOLs) are the two options.
A BL is a striped and signed space exclusively for the use of bicyclists and is
typically 4 or 5 feet wide. A WOL is a shared-use lane that is wider than a standard 12 ft
lane; 15 feet is typically recommended. A third option, a paved shoulder, is similar to a
BL but lacks the formal designation of a bicycling facility.
Following are issues in comparing BLs and WOLs. They are listed in no particular order,
and each item is not necessarily equally important.
BLs are typically touted as increasing bicyclist safety. BLs, and WOLs for that matter,
have never been shown to actually increase safety as defined by
reduced collisions. Both simply provide space and thus comfort to bicyclists, and ease of
passing for motorists. BLs, however, give the illusion of safety
due to a perceived protective effect from the stripe, but ironically exacerbate certain
hazards for the unwary rider, the very rider they are installed to accommodate.
BLs constrain bicyclists in the position where Drive Out, Left
Cross, and Right Hook collisions are more likely, and increase
the hazard from debris (see 6).
Two separate bicycle-motor vehicle crash analyses (Bicycle-Motor Vehicle Crashes in
Chapel Hill, 1993-1995 and 1996-1999) spanning 7 years have shown the three
most prevalent collisions in Chapel Hill to overwhelmingly be the Drive Out, Left Cross,
and Right Hook, crashes that occur at driveway or roadway intersections (see also 2).
Figure 1. Drive Out
Figure 2. Left Cross
Figure 3. Right Hook
Note: the above figures do not reflect BL stripping. Drive Out is shown
with bicyclist on sidewalk.
The above three types of crashes are partly a result of bicyclists being too close to
the edge of the road, and BLs tend to aggravate this problem because of the physical,
operational, and visual separation that BLs produce, and the constraining nature of the
stripe. The educational countermeasure for these types of collisions is Use More Lane or
Take The Lane. This message is thwarted by BLs because they restrict bicyclists to be in
The two aforementioned studies, which are consistent with nationwide reporting, as well
as those undertaken in other communities, have shown the actual risk of bicycle-motor
vehicle collision to be very different than the perceived main risk of the bicyclist being
struck from behind, known as an Overtaking type crash. The request for BLs by some
bicyclists is a reaction to the perceived risk of an Overtaking collision. However, this
crash is so rare, even in the absence of BLs, as to not warrant attention, especially when
one recognizes that the few of these that do occur are typically not preventable with BLs
because of the circumstances under which they occur - riding unlit at night or driving
with distraction are examples. Furthermore, the appeal for BLs is fundamentally a desire
for additional road space, and most people are unaware of the option of a WOL and its
benefits, as well as the little known (except among "experienced" bicyclists)
but significant dis-benefits of BLs.
The three main adult bicyclist crashes occur at junctions, and a BL adds to complexities
at intersections and roads in general. A 5-lane road becomes a 7-lane road when BLs are
added. A WOL does not add to the complexity of the roadway. With BLs, bicyclists wishing
to turn left tend to not merge to the left far enough in advance or at all. Motorists
turning right must turn across the BL. Drivers may improperly wait to allow bicyclists to
overtake on their right, thus obstructing following motor vehicles and creating an
ambiguous situation for bicyclists. A BL encourages bicyclists to overtake motorists on
the right side and to go to the front of the queue. Passing on the right is very risky and
leads to many Right Hook collisions. WOLs enable bicyclist passing on the right, but it is
not as formally legitimized as with BLs. However, BLs can be instructional at
intersections with a right-turn-only lane and where a BL through pocket is striped.
3. Right of Way.
Greater ROW requirements and costs for a standard 12' lane with standard 4' BL (16' total
feet) as compared to a 14' or 15' WOL. Less total width of a WOL means less impermeable
surface to contribute to downstream flooding. The BLs north of Homestead on Airport road
are about 6000 feet long and 5 feet wide, 1 foot wider than is required (17' of total
width including the adjacent lane). Here, 15' WOLs would have saved 24,000 (2 x 6000 x 2)
square feet of impermeable surface, and considerable money in ROW acquisition and roadway
construction costs. Furthermore, the excessively wide BLs have predictably become riddled
In NC, special bicycle facilities "raise a red flag" regarding funding. Money
for bicycling requests comes from small dedicated pots, is limited, and thus more
difficult to acquire. A WOL is not an identifiable bicycle facility and thus may be
"hidden," and also funded from a much larger source of money, the STP. Moreover,
funding for BLs from the small pots requires a local match. This is not the case with
WOLs. WOLs have been the default bicycling "facility" of the NCDOT and the
Division of Bicycle and Pedestrian Transportation for more than 20 years for good reason.
5. Design Standards.
Narrow bicycle facilities have a design standard of 20 mph. In Chapel Hill, the descents
from town center and on other main roads lead bicyclists to routinely achieve speeds of 25
to 40 mph, so BLs are not indicated. High speed bicycling greatly exacerbates the inherent
dangers of curbside riding and BLs in general. At high speeds, bicyclists should be using
the entire lane. The purpose of a striped-off shoulder is to reduce the risk of
run-off-road crashes by motorists, and to provide greater leeway from roadside hazards,
not for motor vehicles to drive on. Why then is it acceptable to ride a bicycle on such a
facility (a BL is essentially a shoulder designated for bicycles) when there is the risk
at high speed? BLs must be on both sides of the street, conforming to the "All or
None" principle. Having a BL on one side of the road only, the ascent, is not advised
due the even greater possibility of attracting wrong way riders. WOLs or regular width
lanes have no design speed limitations that bicycles typically exceed, and may be on the
ascent only, as is the case on parts of Piney Mountain Rd. Thus, where ROW is at a premium
on a hilly road, WOLs can be paired with regular width lanes for even more space and cost
Maintenance and Debris. BLs collect debris, as do shoulders on
any road. Examination of existing BLs proves this. The sweeping action of motor vehicles
results in the debris being swept into the BL where it stays. This debris is
inconsequential and hardly noticeable to motorists, but is a constant hazard for
bicyclists. Sand, tree debris, and gravel are ubiquitous. Gravel itself can cause loss of
control, but also damages tires, causing sidewall cuts (which requires costly tire
replacement) resulting in blowouts and possible loss of control. At the least, debris is
an ever present nuisance in BLs. Thus, BLs require frequent and expensive maintenance,
which unfortunately typically doesn't happen.
Even if regular maintenance were scheduled, the time between sweepings would still be
debris riddled. WOLs require less, if any, maintenance and cost. Because WOLs are narrower
than a regular lane with BL, and since there is no stripe to keep motorists away from
curbside in the absence of bicyclists, the sweeping action of motor vehicles clears debris
from WOLs continuously, pushing it closer to the edge and out of bicyclists' way. However,
there should still be sweeping of WOLs on an as needed basis.
Riding/Perception. BLs are touted as drawing new, but novice,
bicyclists because they "feel" safer. Is it proper to attract novice riders to
potentially dangerous situations because of the perception of safety? Novice bicyclists
fear getting hit from behind, an unlikely type of collision, and so request BLs, the only
on-road accommodation they may know to exist. They don't realize the down sides of BLs nor
the option of WOLs. As bicyclists gain knowledge of the actual risks of riding and how to
reduce these risks, and become aware of the negative issues surrounding BLs, all of this
either by experience or through education, they no longer desire BLs on most roads. It is
argued WOLs serve existing bicyclists well but may do little to encourage would-be
bicyclists unless they are "advertised." WOLs could be marked with "Share
the Road" signs or noted in a brochure or map.
BLs separate and segregate physically, operationally, visually (left turning drivers don't
readily notice BLs which are much narrower than regular lanes), and socially.
§20-4.01 (49) of the NC traffic code says: "...for the purposes of this
Chapter bicycles shall be deemed vehicles and every rider of a bicycle upon a highway
shall be subject to the provisions of this Chapter applicable to the driver of a vehicle
except those which by their nature can have no application."
Thus, bicycle riders have equal rights to the road as do other vehicle operators. A BL
has the effect of sending the message to motorists that bicyclists have less right to be
out of the BL. BLs create the expectation in motorists that bicyclists will and must stay
"where they belong," in the BL. Some motorists make the incorrect assumption
that bicyclists should be on the sidewalk. This can manifest as "Get on the
sidewalk!" yells, honking, or even physical harassment. When on-road space is
specifically outlined for BLs, that assumption is even stronger. "Get in the Bicycle
Lane!" Some places have made laws requiring bicyclists to be in BLs unless there is
justification to be out of them.
A BL has the effect of teaching novice riders that they must remain in that space, no
matter how unsafe it may be. These riders may then not readily learn vehicular bicycling
principles. New bicyclists more readily learn vehicular bicycling principles in WOLs.
Usually, to the right of the painted line is where a bicyclist would be riding whether
there is a stripe or not. But in the situations where she MUST move out of that space: to
make a left turn (depending on bicyclist speed and traffic conditions, the rider may have
to merge out of a BL very far in advance of a turn. Also, not all left turns are made at
intersections. Many are made into midblock driveways where no break in the BL is
provided.); create shy distance from the curb when high speed descending; avoid illegally
parked cars; peds; wrong way bicyclists; debris; whatever; a bicyclist may be treated as
violating a rule. "Those &*%$ bicyclists can't even stay in the lanes we gave
them!" Or worse. "The accident was her fault. She was not in the Bicycle Lane
where she was supposed to be."
It is argued that BLs are visible icons to the legitimacy of bicyclists. But why should
bicyclists rely on BLs for legitimacy? State law says bicyclists are legitimate on all
roads. Do bicyclists want to be legitimate only on BL roads? WOLs or regular width roads
can have "Share the Road" or "Bikes Belong" signs if bicyclist
legitimacy needs to be affirmed, which it doesn't. A BL tends to restrict bicyclists to a
rightmost portion of the road, and this is enforced by some militant drivers. In a WOL or
regular lane, bicyclists are rightly free to ride where they choose. BLs require no
cooperation, and none is manifested. WOLs require and foster cooperation.
9. Sidewalk Riding.
BLs and WOLs reduce the incidence of sidewalk riding, which is good, but the strength of
the effect of each is unknown and subject to local conditions.
10. Wrong Way Riding.
BLs more readily enable wrong way riding. Wrong way riding in BLs is a significant
collision threat with motor vehicles, especially those pulling out of side streets and
driveways, and also with correct riding bicyclists who are in the same path. Imagine the
hazard to downhill bicyclists on Airport Rd. riding north from Rosemary St. if the
bicyclists who currently ride the wrong way on the sidewalk were to ride the wrong way in
a newly created BL. Bicyclists are not as likely ride the wrong way in WOLs, though wrong
way riding can and does happen anywhere.
Overtaking Separation Distance. The separation distance between
overtaking motor vehicle and bicycle is slightly less in a BL than in a WOL, even though a
WOL is narrower overall. This is an ironic finding in that a BL is supposed to provide
"comfort" to bicyclists from passing motor vehicles, yet drivers pass closer
than in a WOL. The ambiguity in a WOL may cause motorists to move over farther. With a BL,
as long as the bicyclist is in her lane and the motorist in his, there is no need to move
over. Perhaps in a WOL the driver tracks down the left lane line, whereas with a BL the
driver centers himself between the two lines or even tracks down the BL.
12. Motor vehicle
speed. BLs narrow the motorists' travel area as compared to a
WOL so may have a traffic calming effect. On the other hand, BLs may result in higher
driver speed when overtaking bicyclists than when in a shared WOL. BLs allow motorists to
pass bicyclists without slowing down. As long as the driver is in his lane and the
bicyclist in hers, why slow down? The ambiguity of a WOL induces motorist caution, thus
slower speed. This has not been formally studied (it would be nearly impossible to
undertake), but it is common anecdotal knowledge among experienced bicyclists.
Vehicle Encroachment. There is greater uniformity of motor
vehicle tracking, and motorists are less likely to encroach on the adjacent travel lane
when overtaking a bicyclist in a BL. However, encroachments are not necessarily a bad
thing. There is no evidence of motorist collisions due to bicyclist induced encroachments.
Moreover, this finding is questionable. The study has design flaws.
Bicyclist Lateral Position. Bicyclists are more likely to ride
further from the edge of the roadway in a BL than in a WOL. This has several advantages,
but also the disadvantage of being passed closer (11). However, why bicyclists ride further
from the roadway edge in a BL is unknown, but could be due to greater bravery on the part
of the bicyclist, or more curbside debris in the BL which forces the rider further out.
15. Buffer Zone.
BLs provide a tangible buffer for pedestrians, especially along roads with no sidewalk
setback from the curb. BLs are also a buffer for drivers pulling out from driveways to
enter the roadway. This is good for drivers, bad for bicyclists who may be obstructed or
struck. WOLs are not a formalized buffer, but provide greater separation distance than a
standard width lane.
BLs are politically difficult to remove once in place. A WOL may be more easily converted
to additional travel lanes. This should not be a problem in Chapel Hill however.
17. Parking. It is argued that
BLs in urban areas diminish the availability of on-street parking, which, from a cyclist's
viewpoint, is not all that bad. However, as with BLs, "No Parking" signs can be
placed along WOLs. However, once painted, BLs have ha habbit of staying in place. In any
case, parking is an anathma to bicycling for several operational (items 1-4) and
philosophical (item 5) reasons:
- The space occupied by parked cars is potentially useful for bicycles to travel on.
Parking narrows the available travel corridor, reducing driver overtaking space and
causing some bicyclists to feel less comfortable.
- Parking turnover, the pulling into and out of spaces, can be a hazard to bicyclists.
- The extended door of disembarking drivers is a hazard to bicyclists who, in error, ride
within a doors width of the parked cars.
- Turning onto a road with on-street parking from side streets is more difficult due to
reduced visibility from the parked cars. Note that motorists also have this problem.
- Some bicyclists feel marginalized because the storage of privately owned automobiles on
a public right-of-way has superseded their concerns, items 1-4 above.
When to use bicycle lanes (or striped shoulders). BLs are
best used, if at all, on higher speed (45 speed limit) roads with few driveways,
intersections, and turning movements for both bicyclists and motorists, the lack of high
speed bicycle descents, and where commitment is made for regular debris cleanup. An
example is 15-501 bypass. (Here, there are four foot shoulders, and these could have been
specified as BLs except that it was easier to fund them as shoulders, and they essentially
function like BLs anyway. But, there is no commitment to debris removal.) WOLs are
appropriate everywhere else. Airport Rd. and Raleigh Rd. both have 15' WOLs from curb face
to line. These function very well for both bicyclists and motorists. Ideally though, they
would be 15' from edge of gutter pan to line, providing even more space. Unfortunately,
BLs locally have been placed inappropriately on low speed roads that would be better
served with WOLs. All of the roads with BLs in Carrboro and Chapel Hill would be easy
places to ride a bicycle without the stripe given the same or similar total available road
Links to other articles debating the wisdom of bike lanes:
Why Bike Lanes are a Bad Idea