Wide Outside Lanes Are Superior to Bicycle Lanes

by Wayne Pein

To make busier roads so-called "Bicycle Friendly," added space allows easier overtaking by motorists and resulting comfort for people on bicycles. On urban design roads this added space can be wide outside lanes (WOLs) or bike lanes (BLs). A WOL is a shared-use lane that is wider than a standard 12 foot lane; 14 to16 feet is typically recommended (Figure 1). A BL is a striped and signed space exclusively for the use of bicyclists and is typically 4 or 5 feet wide (Figure 2). Envision no stripe and signs on a BL road and you have a WOL. A third option, a paved shoulder, is similar to a BL but is typically used on rural design roads without curb and gutter.

Figure 1: Wide Outside Lane

Figure 2: Bike Lane


Following are issues that should be considered in deciding whether to install WOLs or BLs.

1. Safety. BLs are often touted as increasing bicyclist safety. Surprisingly, neither BLs nor WOLs have been shown to actually increase safety as defined by reduced collisions. Both simply provide space, make passing easier for motorists and affording comfort to bicyclists. Similarly, neither has been shown to be more safe than the other. However, proving safety or lack thereof through collision studies is quite difficult.

BLs give the illusion of safety, typically reported as bicyclist comfort, presumably due to a perceived protective effect from the stripe. Ironically, BLs 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 (Figures 3-5) collisions are more likely, the three main risks for otherwise legally riding bicyclists, and increase the hazard from debris (item 5). These crashes occur at driveway or roadway intersections, involve turning or crossing maneuvers, and are not prevented with BLs. Note: The Figures do not reflect BL striping.

Figure 3: Drive Out Collision

Figure 4: Left Cross Collision

Figure 5: Right Hook Collision

The three crashes are partly a result of bicyclists being too close to the edge of the road. BLs tend to aggravate this problem because of the constraining nature of the stripe, and the physical, operational, and visual separation between motor and bicycle traffic that BLs produce. The educational countermeasure to bicyclists for these collisions is RIDE BIG - Use More Lane or Use Full Lane. This message is thwarted by BLs because of the restrictive stripe. Bicyclists might ride curbside in a WOL, but a WOL does not direct them to be in that position.

The actual main risks of bicycle-motor vehicle collisions are thus quite different from the perceived main risk which is the bicyclist being struck from behind, known as an Overtaking type crash. The demand for BLs by some bicyclists is a reaction to the perceived risk of an Overtaking collision. However, this crash is very rare, whether the road is narrow, normal, or wide, with or without BL or shoulder stripes. Motorists have little difficulty avoiding a 5 foot high by 2 foot wide bicyclist riding in the same direction, no matter what the road. The few Overtaking collisions that do occur are typically not preventable with BLs because of the circumstances under which they happen - riding unlit at night or driving with distraction are examples.

Nationwide and local level collision studies have shown that most bicycle-motor vehicle crashes are caused by errors made by the bicyclist. The more common of these errors include riding on sidewalks, failure to obey stop signs and traffic signals or yield as appropriate, wrong way riding, riding at night without lights, and failure to recognize risky situations. The way to prevent these mistakes, as well as collisions in which the motorist is largely to blame, is through education. However, many novice bicycle users think that they know all they need to know. The presence of BLs makes the task of promoting bicycle education even more difficult.

[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 (Figures 1-3).]

2. Design Standards. Scant attention has been paid to the design speed of BLs. The AASHTO Guide for the Development of Bicycle Facilities does not address the issue. California has stated "Bike lanes are not advisable on long, steep downgrades, where bicycle speeds greater than 50 km/h (31 mph) are expected. As grades increase, downhill bicycle speeds will increase, which increases the problem of riding near the edge of the roadway." It can be argued that this specified 50 km/h is too liberal and should be lowered. Regarding the design of separated shared use paths, the AASHTO Guide notes, "Grades greater than 5 percent are undesirable because the ascents are difficult for many bicyclists to climb and the descents cause some bicyclists to exceed the speeds at which they are competent or comfortable."

Since BLs are said to be installed for the explicit purpose of accommodating novices, high speed descents in narrow BLs should be avoided. The laws of physics make 20-40 mph gliding speed on typical descents easily achievable by all bicyclists regardless of experience or ability. At such speeds it is a breach of safety to constrain all bicyclists in a 4-5' BL at the edge of the road. Left Cross and Drive Out threats, the curb itself, natural and motor vehicle induced wind buffeting, and the ever present debris are hazards that demand the rider Use More Lane or Use Full Lane for added leeway and conspicuousness.

The purpose of a paved striped-off shoulder is to reduce the risk of run-off-road crashes by motorists and to provide greater leeway from roadside hazards. It is not for motor vehicles to drive on. Similarly, it is not safe to ride a bicycle on such a facility, a BL or paved shoulder, when there is high speed descending. WOLs or regular width lanes have no design speed limitations that bicycles typically exceed.

BLs must be on both sides of the street, conforming to the "All or None" principle. A BL on one side of the road only, the ascent of a hill for example, is not acceptable due to the great possibility of attracting wrong way riders. Thus, on a hilly road if right of way is at a premium, a WOL on the ascent can be paired with a regular width lane on the descent for even more space and cost savings (item 4).

Basic principles of the road transportation system are one set of rules (uniformity), simplicity, destination positioning (segregation by destination), and cooperation and trust by users. Segregation by vehicle type violates all these concepts. BLs segregate bicycles from other vehicles. There are inherent difficulties and compromises when designing such facilities as HOV lanes (segregation by occupant quota) and dedicated bus lanes. It is no surprise that similar and additional challenges occur when separate space is outlined for bicycling.

[The NCDOT recently determined that left lane HOV lanes are infeasible on I-40 due to the difficulty of exiting right. Similarly, right side BLs make it difficult for bicyclists to exit left at intersections or midblock driveways.]

[In Chapel Hill, the descents on virtually all main roads including Airport Rd., Franklin St., Columbia St., Estes Drive and Estes Dr. Ext., Weaver Dairy Rd., etc. lead bicyclists to routinely achieve speeds of 25 to 40 mph gliding, so BLs are not acceptable. Piney Mt Rd has WOLs on most of the ascents and narrow lanes elsewhere.]

3. Intersections. As noted in item 1. Safety, the three most common adult bicyclist crashes occur at junctions (Figures 3-5). A BL adds to complexities at intersections and roads in general, violating the simplicity principle of roadway design. A 5-lane road becomes a 7-lane road when BLs are added. A WOL does not add to the complexity of the roadway.

Novice bicyclists wishing to turn left tend to not merge to the left far enough in advance or at all, and this error is exacerbated by BLs. Depending on the situation, any bicyclist needing to turn left may have to merge left quite far in advance of the turn, as do motorists, but some motorists would take issue with a bicyclist who is not in the BL (item 7). Thus, all bicyclists, regardless of experience, are deterred from proper vehicular operation by BLs.

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 (Figure 5). WOLs enable bicyclist passing on the right, but it is not as formally legitimized as with BLs.

Right turning motorists turn across the BL rather than merging into it since it is not possible to merge into a 4 to 5 foot wide lane that is for bicyclists only. This can result in Right Hook collisions. Right turning drivers may also improperly, albeit courteously, wait in the through lane to allow bicyclists in a BL to overtake on their right. This obstructs following motor vehicles and creates an ambiguous situation for the bicyclists.

4. Right of Way and Funding. A 4 or 5 foot BL beside a standard 12 foot lane (16 or 17 feet total) requires more space and costs more in ROW acquisition and construction than a 14 or 15 foot WOL. Less total width of a WOL means less impermeable surface to contribute to downstream flooding.

While state and local funding programs differ around the country, bicycling specific facilities typically are funded from relatively small, dedicated sources. Thus, money is limited, and bicycling and walking projects (BLs, off road paths, sidewalks) often compete among themselves for funding.

Although BLs can in theory be funded from much larger sources, such as the Surface Transportation Program (STP) category, DOT's are often loathe to do so. WOLs need not be an identifiable bicycling facility, and thus may be more easily funded. This, in combination with the typically lower cost of WOLs compared to BLs, means WOLs can be more likely to be constructed.

[The BLs north of Homestead Rd. on Airport Rd. in Chapel Hill are about 6000 feet long and 5' wide, 1' wider than is required. 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.]

5. Maintenance and Debris. BLs collect debris, as do shoulders on any road. The sweeping action of motor vehicles results in the debris being whisked into the BL where it stays. This debris is barely noticeable to motorists, but is an ever present nuisance and hazard for bicyclists. Tree debris, trash, sand, and gravel are ubiquitous. Gravel itself can cause loss of control, but also damages tires, causing sidewall cuts (which requires costly tire replacement), possibly resulting in blowouts and loss of control. Thus, BLs require frequent and expensive maintenance, which unfortunately typically doesn't happen. Even if regular maintenance were scheduled, the time between sweepings may still be debris riddled.

WOLs require less, if any, maintenance and cost. Because WOLs are typically 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 cleaning of WOLs on an as-needed basis.

6. Induced Riding/Perception. BLs are touted as drawing new and novice bicyclists because they report they "feel" safer or are more "comfortable." While opinion surveys are illustrative, one must reasonably question the significance of the attitudes of those who by definition are not familiar with all of the issues. Furthermore, preferences and opinions do not void the actual safety, fiscal, maintenance, and liberty (item 7) costs of BLs.

The appeal for BLs is a desire for additional road space. Novice bicyclists fear getting hit from behind, the unlikely Overtaking type of collision, or are otherwise intimidated by overtaking traffic, 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 often no longer desire BLs on most roads.

It is argued WOLs serve existing bicyclists well but may do little to encourage would-be bicyclists who are attracted to BLs which are "advertised." However, there is no indication that BLs would induce substantially, or any, more riding than would well advertised, perhaps with signs, WOLs. WOLs could be marked with "Share the Road," "Bicycle Route," "Bikes Belong" or some similar sign in an effort to appeal to prospective riders.

It can be argued that it is not ethical to attract novice riders to potentially dangerous situations because of the mere perception of safety afforded by BLs. Comfort sometimes results in complacency and a false sense of security. A BL, especially, or a even WOL, may seem safe, but are only as safe as the bicyclist riding.

7. Sociology. BLs segregate bicycle traffic 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. This means that bicycle users are entitled to use of the full lane, since no vehicle operator is required to share his or her lane. Bicyclists usually willingly share their lane with overtaking motorists, but there are many situations when the bicyclist must use the full lane.

A BL has the effect of teaching novice riders that they must remain in that space. Usually, on the right side of the lane is where a bicyclist would be riding whether there is a stripe or not. But in the situations where she must move left out of that space: to make a left turn at an intersection or mid block; create shy distance when high speed descending; avoid parked cars, pedestrians, wrong way bicyclists, debris, etc., a bicyclist may be treated as violating a rule. The threat of motorist coercion makes leaving the BL unappealing for all bicyclists regardless of experience.

A BL sends the message to motorists and bicyclists alike that bicyclists have less right to be out of the BL. Where BLs exist, the remainder of the road becomes defacto Motor Vehicle Lanes. BLs create the expectation in motorists that bicyclists will and must stay "where they belong," in the BL. At the least, a bicyclist not in the BL is considered in an unexpected position.

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 Bike Lane!" Some places have made laws requiring bicyclists to be in BLs unless there is specific justification to be out of them.

BLs are requested and prescribed for the worthy cause of making the streets "Bicycle Friendly" so that some bicyclists are more "comfortable" and perhaps more riding will result. But this is at the cost of reduced freedom of all bicyclists to use the remainder of the road, which, with BLs, has now become the Motor Vehicle Lanes. In a WOL or regular lane, bicyclists are free to ride where they choose. "They that can give up essential liberty to obtain a little temporary safety deserve neither liberty nor safety." Benjamin Franklin, Historical Review of Pennsylvania, 1759. BL proponents espouse segregation, while WOL adherents seek integration.

It is argued that BLs are visible icons to the legitimacy of bicyclists. State law says bicyclists are legitimate on all roads (except limited assess roads). Do BL proponents want to be legitimate only on BL roads? Again, WOLs or regular width roads can have "Share the Road," "Bike Route,"or "Bikes Belong" signs if bicyclist legitimacy needs to be affirmed.

As previously noted (item 2), the road system is based on mutual cooperation and trust by users. The BL stripe removes any need for cooperation, resulting in closer and likely higher speed overtaking (item 9). BL proponents fundamentally mistrust other road users. WOLs, like normal width shared lanes, require and foster cooperation and trust.

8. Sidewalk and Wrong Way Riding. BLs and WOLs tend to reduce the incidence of sidewalk riding, but the strength of the effect for each is unknown and subject to local conditions. Sidewalk bicycling has been shown to have about twice the accident rate as bicycling on the roads.

BLs more readily enable wrong way riding, possibly because the BL is viewed as a safe haven. Wrong way riding in BLs and elsewhere 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. Bicyclists are not as likely ride the wrong way in WOLs, though wrong way riding can and does happen anywhere.

While sidewalk riding should be discouraged, sidewalks will likely always be a perceived attractive place to ride by some bicyclists. For those too timid to use an available WOL, the sidewalk can be an alternative.

9. Overtaking Operations. The separation distance between overtaking motor vehicle and bicycle has been found to be about 6" less in a BL than in a WOL. It is ironic that a BL that is supposed to provide "comfort" to bicyclists from passing motor vehicles also encourages motorists to pass closer. Perhaps with a BL, as long as the bicyclist is in her lane and the motorist in his, there is little perceived need on the part of the motorist to move over.

Related, 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. This may be another manifestation of motorists not moving over, or moving over as far, for bicyclists in a BL. It could also be due to less total space afforded by a WOL, which could be addressed with wider WOLs. There is no evidence of motorist collisions due to overtaking-bicyclist encroachments.

Bicyclists tend to ride further from the edge of the roadway in a BL than in a WOL. This has several advantages. It is not known why bicyclists ride further from the roadway edge in a BL. It may be due to more curbside debris in the BL which forces the rider away from the edge, or the rider may be emboldened by the stripe. In any case, riding further from the edge is a positive behavior, and one which is espoused by experienced bicyclists whether there is a BL stripe, the road is wide, or narrow.

It is argued that BLs narrow the motorists' travel area so may have a traffic calming effect. However, this effect, if it exists at all, is likely to be location specific. Many narrow rural roads, for example, are quite high speed. It also may be that motorists pass bicyclists at higher speed on a BL road than in a shared lane. This is often reported by experienced bicyclists. Again, as long as the motorist is in his lane and the bicyclist in hers, there is little perceived need to slow down. Possibly the ambiguity of overtaking in a WOL encourages motorist caution, thus slower speed.

Conclusions. 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. Providing WOLs on main roads enables bicycling by all abilities of rider at the least cost without artificially introducing complexity and problems. Many WOLs exist on North Carolina roads, but they often go unnoticed because they unglamourously do their job. Note that many conspicuous "problem" streets have narrow lanes.

[In Chapel Hill, five lane Airport Rd. and Raleigh Rd. both have 13' WOLs from gutter pan edge (virtual) to line. These function acceptably, but ideally should be 15 feet. Other streets with WOLs include Estes Dr. from the library to Curtis Rd., eastbound Franklin St. in front of University Square, Pinehurst, parts of Piney Mt. Rd., and others.]

BLs may be warranted on limited access highways which have on and off ramps, the lack of driveways and intersections, and very high speed motoring. In such situations, the absence of turning movements and cross traffic, and large speed differential makes BLs a more viable option. The BL should be a minimum 6 feet wide with ample clearance to lateral obstructions. Regular debris removal should be scheduled.

Bicycle riding is unfortunately often made out to be - by injury control professionals, the media, and bicyclists themselves - more difficult and dangerous than it actually is, requiring "elite" skill or BLs. Given the problems of BLs, it is apparent that BLs require as much or more skill than WOLs, which are simply wider regular roads.

The inherent baggage BLs bring is not worth any speculative reward of better and more bicycling beyond what can be expected by providing WOLs. The best way to make most busy roads "Motorist Friendly in the Presence of Bicyclists, Resulting in Bicycling Friendliness" is to provide WOLs. They are simple, and simply better.