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Bicycle 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.

1. Safety. 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).

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Figure 1. Drive Out

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Figure 2. Left Cross

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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 them.

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.

2. Intersections. 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 with debris.

4. Funding. 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 savings.

6. 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. bikelanedebris.jpg (16845 bytes)

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.

7. Induced 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.

8. Sociology. 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.

11. 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.

13. Motor 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.

14. 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.

16. Permanence. 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:

  1. 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.
  2. Parking turnover, the pulling into and out of spaces, can be a hazard to bicyclists.
  3. The extended door of disembarking drivers is a hazard to bicyclists who, in error, ride within a door’s width of the parked cars.
  4. 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.
  5. 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 space.




Wayne Pein



This article is the result of the author's analysis of Wide Outside Lanes vs Bike Lanes for the Chapel Hill, North Carolina area for use in various Local Forums. 

It appears here as a basis for discussion of the relative merits of these two alternative forms of providing on-roadway cycling facilities.


Links to other articles debating the wisdom of bike lanes:

Why Bike Lanes are a Bad Idea


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