Comments on the AASHTO Guide for the Development of New Bicycle Facilities


Chapter 2: Design cont'd.

Bicycle Paths

General

John Forester: This section should be deleted. The bike path program of the last 20 years has been a failure. (Note: this statement is taken from a lengthy discussion, included in the author's letter; see attached)

Bill Feldman: There should be a statement in the introductory paragraph which states that due to the many problems involved, bicycle paths parallel and adjacent to existing roadways are generally not recommended.

Diane Bishop: It would be appropriate to discourage use of sidepaths, particularly if a certain number of street crossings per mile are encountered.

Bill Feldman: Delete the following from ¶ 2 of Bicycle Paths, p. 14: "in much the same way as freeways are intended for the exclusive or preferential use of motor vehicles."

John Forester: No things that fit the definition exist. There are only multi-use paths, with all the problems inherent in such facilities. It is pointless to spend lots of money on a facility with high design speed when the traffic that will exist on it makes it too dangerous to travel at that speed.

Bill Feldman: Delete braketed text from second paragraph: "Bicycle paths should be thought of as extensions of the highway system that are intended for the exclusive use of bicycles [in much the same way as freeways are intended for the exclusive or preferential use of motor vehicles]."

AASHTO's proposed new section: The AASHTO Task Force has created an entirely new section as titled below.

"Separation between Bicycle Paths and Highways

"When two-way bicycle paths are located immediately adjacent to a roadway, operational problems may occur. Some problems with bike paths located immediately adjacent to roadways are as follows:

"1. Unless paired, they require on direction of bicycle traffic to ride against automobile traffic, contrary to normal rules of the road.

"2. When the bicycle path ends, bicyclists going against traffic will tend to continue to travel on the wrong side of the street. Likewise, bicyclists approaching a bicycle path often travel on the wrong side of the street in getting to the path. Wrong way travel by bicyclists is a major cause of bicycle/automobile accidents and should be discouraged at every opportunity.

"3. At intersections, motorists entering or crossing the highway often will not notice bicyclists coming from their right, as they are not expecting contra-flow vehicles. Even bicyclists coming from the left often go unnoticed, especially when sight distances are poor.

"4. When constructed in narrow roadway right-of-way, the shoulder is often sacrificed, thereby decreasing safety for motorists and bicyclists using the roadway.

"5. Many bicyclists will use the highway instead of the bicycle path because they have found the highway to be safer, more convenient, or better maintained. Bicyclists using the highway are often subjected to harassment by motorists who feel that in all cases bicyclists should be on the path instead.

"6. Bicyclists using the bicycle path generally are required to stop or yield at all cross streets and driveways, while bicyclists using the highway usually have priority over cross traffic, because they have the same right-of-way as motorists.

"7. Stopped cross street motor vehicle traffic or vehicles exiting side streets or driveways may block the path crossing.

"8. Because of the closeness of motor vehicle traffic to opposing bicycle traffic, barriers are often necessary to keep motor vehicles out of bicycle paths and bicyclists out of traffic lanes. These barriers can be a hazard to bicyclists and motorists, can complicate maintenance of the facility, and can cause other problems as well.

"For the above reasons, bicycle lanes, wide curb lanes, or bicycle routes (shared use) may be the best way to accommodate bicycle traffic along highway corridors depending upon traffic conditions."

Width and Clearance

Diane Bishop: More specifics are needed on: 1) recommended width instead of minimums; 2) a formula for determining width which takes into account volume and use; 3) discussion on determining when to separate uses. Should paths be rated like streets-arterials and collectors?

Sharon Todd: Why not state preferred widths first and then the minimum?

AASHTO: Last sentence of first paragraph modified, deleting the bracketed items and adding those emphasized as follows: "Under certain conditions it may be necessary or desirable to increase the width of a bicycle path to 12 feet (3.7 m); for example, because of substantial [bicycle volume,] number of all-terrain bicycles in the bicycle flow, probable shared use with joggers and other pedestrians, use by large maintenance vehicles, steep grades, and where bicyclists will be likely to ride two abreast."

Sharon Todd: We don't understand the importance of this addition.

Sharon Todd: Revise the first 5 sentences of paragraph 1, deleting bracketed items and adding those emphasized as follows: "[Under most conditions,] a desirable minimum all paved width for a two directional bicycle path is 10 feet (3m). [In some instances, however, a minimum of 8 feet (2.4m) can be adequate. This minimum should be used only where the following conditions prevail: 1) bicycle traffic is expected to be low, even on peak days or during peak hours; 2) pedestrian use of the facility is not expected to be more than occasional, 3) there will be good horizontal and vertical alignment providing safe and frequent passing opportunities, 4) the path will not be subjected to maintenance vehicle loading conditions that would cause pavement edge damage.] Paths narrower than 10 feet are not recommended as they do not permit safe and frequent passing opportunities where there is high bicycle use, especially where pedestrian use is frequent. Also, a narrow path is subject to pavement edge damage from maintenance vehicle loading conditions. (A segment of path less than 10 feet wide may be acceptable or necessary for short durations, such as when passing between buildings or utility poles that cannot be moved, or when crossing bridges that cannot be modified, or unusual items such as above-ground pipes to underground storage tanks. These should be treated on a case-by-case basis.)

Sharon Todd: Addition to the last sentence, first paragraph: "...and in large urban areas."

Peter Lagerwey: Paths, like freeways, often fill to capacity. Capacity appears to be a function of path width and user mix. For example, a ten-foot multi-use path that has 70% bicyclists and 30% pedestrians appears to have a capacity of about 3000 users/day. However, a ten-foot pedestrian path appears to have a capacity of over 5000 users/day. I don't think we have the necessary research data to correlate path widths and user mix to capacity. However, I do think it would be appropriate to discuss path capacity in the context of meeting demand. In my opinion, the question should concern what is the desired use, not only what is the anticipated use. We will end up with 20-foot wide parking lots of we try to meet total demand in urban areas.

Don Lund: The paved width for a two-way bike path should be eight feet minimum. If the bicycle traffic is equal to or greater than 60 bicycles per peak hour, the minimum width of 10 feet should be used. Also, if maintenance vehicles are expected to use the bike path, a 12-foot minimum paved width is recommended.

Tom Walsh: Re: suggestions that the 8-foot minimum bike path width be increased to 10 feet: While it may be appropriate to add a statement on page 16 regarding the characteristics of all-terrain bicycles, my experience is that the 8-foot width is ideal for most applications.

Rick Knapp: It is indicated that wider bike paths may be appropriate "where bicyclists will be likely to ride two abreast." Based on experience to date, this is likely on every bike path. It may be appropriate to indicate that it is likelyand that fact should be considered in determining the width. On pages 20 and 24, installation of a centerline is indicated as a consideration. I believe that after numerous lawsuits and large judgements against implementing agencies relative to head-on bicycle accidents on bike paths, it is time to call for a centerline stripe on two-way bike paths as a standard.

Bill Feldman: Delete paragraph about minimum width of one-directional bicycle path.

Rich Nowack: On page 16, clearance widths [between a path and adjacent highway] are referenced to the edge of roadway. Since this is the edge of shoulder by AASHTO definition and since shoulder widths vary, the reference point should probably be the traveled way.

Ken Buckeye: A frequently asked question is when to provide railings on bikeways near steep adjacent slopes, retaining walls or near water. In addition, how high should the railing height be when it is "x" feet from the edge of the path. There are some arguments against using the 4.5 foot railing height in all cases, especially when the railing is a substantial distance from the edge of the path. These arguments including being a visual obstruction for users, and aesthetic considerations.

Dan Burden: More separation is needed on slopes, especially for paths above a canal, riverbank, or other steep embankment. The separation should be 6 feet at a minimum, and other considerations should be given, including some type of positive barrier or other means to keep a rider from going down a steep slope.

Diane Bishop: Help with determining what is a hazard near the path would help and knowledge of the desired treatment. For instance, what is the maximum allowable slope, when do you use guardrails (handrails) and what should be their design?

Diane Bishop: When do you use landscaping or markings and what do you do when the recommended 3 foot shy distance is not available?

Diane Bishop: Sometimes vertical clearance is quite low. If it were 7'-6", would you sign it? You wouldn't necessarily want to close the facility if you couldn't meet the minimum.

X: Need typical right of way widths for bicycle facilities plus drainage ditches.

Ken Buckeye: The study "Effect of Bicycle Accommodations on Bicycle/Motor Vehicle Safety and Traffic Operations" may provide recommendations for shoulder widths under different traffic volumes and road designs. In the Mn/DOT Bikeway Design Manual, several roadway design tables identify shoulder widths necessary to achieve "good," "fair," "poor," and "unsatisfactory" bikeways as well as in rating roads for bicycling suitability in our mapping effort. Although these are far from perfect, they are a good guideline for planners and represent a statewide "standard" for bikeways development.

Rick Knapp: On page 16, at the bottom, it indicates that a suitable barrier "may be considered" when a bike path is separated by less than 5 feet from a highway. That should be a requirement; otherwise, some agency will implement two-way bike lanes on one side of the street. On page 18, it goes on to say that the barrier "should be designed so that it does not become a hazard itself." Generally, any fixed object along side a roadway or bikeway represents a hazard, but hopefully not as great as an oncoming motor vehicle. I would suggest that sentence be deleted or rewritten to emphasize a design that is smooth and that is at least 2 feet, preferably 3 feet from the pavement.

Andy Clarke: It a divider is provided between a bike path and a highway, shouldn't the path be wider?

Sharon Todd: I would like to see "and the distance between the edge of the roadway and the bicycle path is less than 5 feet (1.5m)," (p. 16) deleted from this section.

Sharon Todd: Re paragraph 4, 2nd sentence: "When this is not possible...a suitable physical divider, such as a fence" No ODOT engineer would readily approve of a barrier so close to the road.

Curt Yates: Re: "When the distance between the edge of the roadway and path is less than 5 feet, a suitable physical divider, such as a fence, dense shrubs, or other barrier may be considered." To advise that a barrier such as dense shrubbery could make a sidewalk bicycle path acceptable seems a dangerous error. Such a barrier could significantly decrease bicycle safety at intersections, since bicyclists would be even more likely to appear out of nowhere at each intersection crossing. We feel it is a mistake to encourage the two-way path parallel to a highway under nearly any conditions.

Bill Feldman: Difficulties of integrating paths adjacent to the roadway into existing road network should be pointed out; discourage these facilities.

Rich Nowack: More discussion is needed on the proper use of bollards and proper side slope design with associated protection (i.e. guardrails)

Peter Lagerwey: The guide does not specify if railing should be installed along paths where there are steep embankments. In general, we have required railings whenever the top of an embankment comes within five feet of a paved path.

Figure 3

Peter Lagerwey: Graphic is misleading; one has to read the text to discover that the minimum width for a multi-use path is ten feet, not eight. Designers look at the graphic, but do not read the text. While the Guide discourages mixing bicycles and pedestrians, the reality is that there is no such thing as a bike-only path. The eight foot width is only appropriate when an alternative parallel route is provided for pedestrians.

Jim Clark: When an engineer sees figure 3, showing a bikepath of minimum 8 foot width, that's all you're likely to get. Why not state the desirable width (i.e. 10 feet) then suggest an 8 foot minimum when the desirable 10 foot is not possible.

Design Speed

Rick Knapp: The reference to unpaved bike paths should be deleted. Unpaved paths should be considered "recreational trails," not bike paths. Although agencies may permit bicyclists on such trails, they should not be labelled as bike paths, as they will be inherently unsafe due to some of the reasons emphasized on page 9 where pavement surface is discussed. (See discussion in Section 1003.5 of the California Highway Design Manual, Attachment 3)

Andy Clarke: Trail/unpaved path design is a big omission that should be corrected this time around. The bicycle path chapter could be divided into paved and unpaved.

Horizontal Alignment and Superelevation

Diane Bishop: Some engineers like to include curves in their design for speed control near a street intersection or other decision point. A discussion of this practice would help (I'm not sure it's a great idea). Similarly, should it assumed that speeds will be slower at the beginning/end of a path? If terrain dictates, could the beginning/end curves be tighter than the rest of the path? If so, the curve radii table should include slower speeds. I assume from what the book does say that signs would be necessary for speeds slower than 20mph.

Glenn Grigg: Bicycles do not require super-elevation on curves, just added width. Highway engineers seem to have a hard time visualizing how bicycles lean when turning. It is very important that this section be corrected.

Don Lund: Superelevation transitions and minimum curve radii for reverse superelevation conditions need to be discussed in the new Guide.

Don Lund: Combination of horizontal alignment and vertical alignment should be discussed briefly and reference made to the AASHTO Green Book.

Andy Clarke: Last paragraph: Re: the negative effects of substandard curves being partially offset by pavement widening: Substandard designs will make facilities less desirable, less safe. Readers should be made aware of this.

Sharon Todd: Re; formula given on page 18: This is true where e is (+). Path can be made where e is (-) but radius will be longer.

Sharon Todd: Re: Add "+ or -" to 2nd paragraph, page 19: "Based on a superelevation rate (e) of + or - 2 percent..."

Grade

Don Lund: Include a statement to the effect that sustained grades of no more than 2 percent should be maintained if a wide range of riders is anticipated.

Diane Bishop: We can't always keep the grade at 5% or less and need more direction for those circumstances, particularly if curves are needed. Would some extra super help on the curves?

Sharon Todd: More guidance is needed on grades. Note: Sharon enclosed a copy of an ODOT policy on grades on paths, shoulders, wide curb lanes, and bike lanes.

AASHTO: Add in the following at the end of the section: "Grades steeper than 3 percent may not be practical for bicycle paths with crushed stone surfaces."

X: What to do when all grades are in excess of 5 percent?

John Forester: Limitations on grade and length of grade are unworkable. You have to get over the mountains that exist. Any reasonable highway engineer knows that you minimize slopes where possible without too much increase in cost, and the same principle applies to bike paths.

Sight Distance

Don Lund: Combined design speeds for both directions need to be taken into account when determining the stopping sight distance on two-way bike paths.

Diane Bishop: A discussion on designs to address personal security might be appropriate for this section.

Steve Yost: The eye height for a cyclist is stated to be 4.5 feet and the object height (for calculating stopping sight distance) is assumed to be zero. For determining bicycle braking distance, the sight distance in the descending direction (where "G" is negative) controls the design of a two-way bicycle facility. Has consideration ever been given to use of 3.5 foot eye height for cyclists when working the calculations? After all, a cyclist is usually in the crouched position when descending a slope (therefore lower than 4 feet) and the cyclist's sight is somewhat diminished just by being in this crouched position (due to a limited range of motion of the head and neck). In the AASHTO Green Book, the height of a driver's eye is considered to be 3.5 feet above the road surface.

Intersections

AASHTO: Delete bracketed items from 1st paragraph, 2nd sentence: "If alternate locations for a bicycle path are available, the one with the [fewest intersections and/or] the most favorable intersection conditions should be selected."

Sharon Todd: 1st paragraph, 3rd from last sentence and last sentence: "...a grade separation structure may be the only possible or practical treatment...however the cost of a grade separation will be prohibitive." This means "no build."

Sharon Todd: 1st paragraph, second from last sentence: "Unless bicycles are prohibited from the crossing highway, providing for turning movements must be considered." What? Doesn't fit.

AASHTO: Delete bracketed items and add those emphasized to 2nd paragraph: "The type of traffic control to be used (signal, stop sign, yield sign, etc.) should be [selected by application of the warrants of the MUTCD] in accordance with the MUTCD. [Bicycles should be counted as vehicles in these determinations and thus, bicycles may be given priority at some intersections.]" Also deleted from the end of this paragraph was a draft suggestion, apparently from an earlier revision: "[At crossings with very infrequent automobile traffic, such as residential or commercial driveways, bicycles may be given priority. Adequate sight distance and proper signing should always be provided.]"

Diane Bishop: Recommendations for reasonable traffic control at path/street intersections would be helpful (perhaps MUTCD is a better place). A vision clearance triangle similar to streets should be established. A discussion of ramp size would be helpful.

Bill Feldman: There should be a statement which stresses the importance of properly integrating the bike path into the existing system of roadways for those bike paths which begin and end at existing roadways. Care should be taken by proper design or signing to ensure that bicycle traffic isn't just dumped somewhere, but directed safely (in the proper direction) onto the intersecting roadway.

Dick Unrein: Expand to include warrants for grade-separated structures; include volumes, delay times, safety, and cost factors.

Andy Clarke: Re: the sentence: "Bicycles should be counted as vehicles in these determinations and thus, bicycles may be given priority at some intersections." Parallel bike path should be given the same priority as the main road over side roads, driveways, etc.

Curt Yates: it is stated that "it is preferable that the crossing of a bicycle path and a highway be at a location away from the influence of intersections with other highways." On the contrary, an existing signalized intersection may be the best place for a bicycle path crossing of a busy multi-lane highway. It seems a mistake to encourage midblock crossings of such highways.

Peter Lagerwey: Private driveways crossing paths: The Guide does not address the issue of who has right-of-way at private crossings. The public thoroughfare (the path) should have priority over private crossings; therefore stop and yield signs should be posted for the motor vehicles, not the path users.

AASHTO: added paragraph at end of section: "Curb-cuts at intersections should be the same width as the bicycle paths. Curb-cuts and ramps should provide a smooth transition between the bicycle paths along the roadway."

Figure 5: Sight Distances for Crest Vertical Curves

Rick Knapp: Definition of "S" refers to "site" rather than "sight."

Figure 6: Lateral Clearances on Horizontal Curves.

AASHTO: Add the following note to this figure: "Lateral clearances on horizontal curves should be calculated based on the sum of the stopping sight distances for bicyclists traveling in opposite directions around the curve."

Signing and Marking

Andy Clarke: Safe access and egress for cyclists must be provided. Signposting should begin away from the actual start of the path.

Diane Bishop: More discussion of use of a centerline would help; for instance what do you do if you feel the path is too narrow to add a centerline? This might be a good place to recommend against separating bikes and peds on one trail.

Pavement Structure

Diane Bishop: We need a recommendation for shoulder surfacing (3/4 is too loose yet is same as subbase).

Diane Bishop: Replace "ten" with "fifteen" as follows in Paragraph 5, sentence 2: "At unpaved highway or driveway crossings of bicycle paths, the highway or driveway should be paved a minimum of [ten] fifteen feet on either side of the crossing to reduce the amount of gravel being scattered along the path by motor vehicles."

AASHTO: Delete bracketed item and add emphasized one to Paragraph 5, sentence 2: At unpaved highway or driveway crossings of bicycle paths, the highway or driveway [should] may be paved a minimum of ten feet on either side of the crossing to reduce the amount of gravel being scattered along the path by motor vehicles.

Structures

AASHTO: Revise the first sentence as follows, adding "drainage facility,": "An overpass, underpass, small bridge, drainage facility, or facility on a highway..."

Bill Feldman: There should be an introductory statement to the effect that for bicycle traffic (as for motor vehicles) structures are a key link in the transportation system and to avoid having these facilities acting as barriers to bicycle traffic, all structures should be designed to accommodate shared use to the fullest extent practical by providing paved shoulders or wide curb lanes.

Ralph Hirsch: Mention stairs and ramps, although they can be significant barriers or aids to bicyclists; illustrations would help.

X: Mention criteria for constructing bicycle/ped overpasses and merits of steps vs. ramps to reach the top.

Peter Lagerwey: Mention advantages/disadvantages of overpasses and underpasses. Overpasses tend not to be used, cannot be built to 20 mph design speeds without long approaches, and raise aesthetic concerns. Underpasses have security implications and may invite debris and graffiti.

Dan Burden: Bridges continue to be a nightmare for the average bike rider. Minimum widths (6 foot shoulders) need to be specified. Minimal openings for longitudinal and lateral seams, and recommendations for other surface conditions need to be stressed.

Peter Lagerwey: With respect to a path crossing an existing highway bridge: can a five foot separation between a path and the edge of the bridge and the motor vehicle lane substitute for a 4.5 foot railing? Logic would say "yes" since a five-foot separation between a path and a motor vehicle lane is already allowed.

Steve Yost: I question the minimum 4.5 feet fence height along bicycle paths and lanes over bridges. This seems to be too low. Does research bear this minimum to be acceptable?

Steve Yost: Do we really want handrails attached to the top of a bridge barrier at handlebar height?

Dick Unrein: A separate section on Railings, Fences, and Barriers should be provided with designs, situations, approach angles and sight distances.

AASHTO: the following sentence had been added to the end of the 2nd paragraph (Railings) during their revision process but later removed: "Railings or barriers with rub rails may also be considered for some small drainage structures."

Diane Bishop: In the option of using sidewalks as one-way or two-way facilities, an obvious addition is the fact that the bridge deck doesn't have room.

Sharon Todd: Re: paragraph 5 ("One option is to carry the bicycle path across the bridge on one side"). This contradicts paragraph 2 of the Bicycle Path section on page 14.

Bill Feldman: I don't think the second option (para. 6) is viable. How can one transition a bi-directional bike path (onto one side of a roadway) into bike lanes without having bicycle traffic cross the roadway at both ends of the bridge? I suppose this might be ok in some rare instance where bicycle traffic doesn't have to cross "at grade." Wide curb lanes should be provided anyway if at all possible.

Andy Clarke: Paragraph 5: add in factor #4 in deciding to carry a bike path across a bridge on one side: "(4) safe crossing facility"

Sharon Todd: [Consider the ODOT policy on Guidelines for retaining walls on bicycle projects; Susan enclosed a copy; see attached letter.]

Curt Yates: it is stated that a third option for bicycle path bridge crossing is to "use existing sidewalks as one-way or two-way facilities." To condone the use of a bridge sidewalk for two-way bicycle traffic seems an error, since it encourages riding against traffic with no separation except a curb. (In such a situation, the addition of a physical barrier between the highway and sidewalk might be useful, since there are no intersections on a bridge. However, this option is not mentioned.

Sharon Todd: Re: option 3 (paragraph 7): This contradicts the sidewalk and multi-use discouragement sections. Must make it clear that the bridge presents an extenuating circumstance and that the sidewalk design is not to be continued far beyond its abutments.

AASHTO:Added to the end of paragraph 7 regarding option 3: "Under certain circumstances, the bicyclist may be required to dismount and cross the structure as a pedestrian."

Andy Clarke: Re: AASHTO's additional language at the end of paragraph 7, it should be noted that making cyclists dismount destroys the continuity and attractiveness of a route and should be a last resort before closure.

X: Give criteria for inclusion of retaining walls.

Andy Clarke: New bridges should accommodate bicyclists.

Peter Lagerwey: path next to active rr tracks: guidance needed. We treat rr tracks like any other motor vehicle lane; we require paths to be at least five feet from edge of rail. This also allows paths to meet most state regulations requiring 8.5 feet of clearance from center of track to any obstruction.

Bill Feldman: Delete second option for carrying bike path across bridge (wide lanes or bicycle lanes).

Curt Yates: Perhaps Chapter 2, Roadway Improvements, should include a "structures" section. Including structures only under Chapter 3, Bicycle Paths, seems incomplete and confusing.

Drainage

Dan Burden: Many bike paths continue to be built with minimal consideration for drainage, especially on parallel bike paths. Some consideration in wording should be added to address the need for a swale or other treatment to interrupt the water flow discharge from the highway to the bicycle path. Some minimal elevation is needed in areas likely to pond.

Diane Bishop: How close could the ditches be (or how deep) before they pose a hazard?

X: More detail needed on: drainage ditches, runoff, swamps and swales, puddling, ten-year flood levels, floodplains, culverts vs. bridges.

Rick Knapp: It states that "ditches should not create hazards for bicyclists." That sentence should be reworded to state that they "should be designed in such a way that they do not create hazards for bicyclists."

Lighting

Diane Bishop: I would appreciate more information on when to light a path; perhaps tying it to volume of use and/or location and encouragement. Spacing and height, as well as the intensity listed would be useful.

X: Need appropriate height of light posts along bikeways

Andy Clarke: Change the 4th sentence as follows: Lighting should also be [considered] provided through underpasses or tunnels

Andy Clarke: Change the last sentence as follows: "Luminaires and standards should be at a scale appropriate for a pedestrian or bicycle path and narrow enough poles for a U-lock."

Restriction of Motor Vehicle Traffic

Don Lund: A section is needed on barrier posts and bollards. When barrier posts are used to prevent motor vehicles from entering the bike path, the barriers must be at least 3 feet in height.

Diane Bishop: A standard for marking in advance of bollards would be useful. Should the bollards be flexible? How tall Sleeves in the pavement (for locking the bollard) need a design which isn't a hazard when the bollard has been removed.

Tom Walsh: This section could be accompanied by sketches of a design detail that has proven effective for each of the two physical barriers described. Reference to use of exclusion sighs consistent with section 2B-28 of the MUTCD might also be added.

Bill Feldman: Barriers to keep out m.v.'s might be hazards to bike traffic.

Peter Lagerwey: The Guide suggests a five-foot spacing for bollards. How many bollards are advisable? Having two bollards directs bicycles from both directions into the center. Having one or three bollards works best.

Peter Lagerwey: No guidance as to when bollards are appropriate. We generally do not put them at private crossings.

Peter Lagerwey: How far should bollards be from intersections? Bring them back away from the intersections. Bicyclists slow up in the intersection to negotiate the bollards if they are too close to the curb. This increases exposure time and takes the cyclist's attention away from watching turning motor vehicles.

Multi-use

Sharon Todd: Remove language on sidewalks and move to a separate section.

Susan Kavulich: The use of bicycle paths seems to be changing in the last few years with the growing popularity of mountain bikes, and the current Guide doesn't cover this type of facility. Multi-use trails for mountain bikes, equestrians, hikers, etc., seem to be proliferating. The Guide really needs to delve more into standards for multiple uses of a trail, and guidelines for separation of different trail users within the same right-of-way. Our Dept. of Natural Resources is researching the issue of multi-use rural trails and I'll pass along to you any information that may help with this section of the Guide.

AASHTO: Add the word "skateboarders" to the list of users in paragraph 2, sentence 4.

Curt Yates: Sidewalk type facilities: Our biggest complaint with this section has been regarding its treatment of sidewalk bike paths. Because this undesirable type of facility continues to be a popular request from our local areas, we would like to see a stronger recommendation against sidewalk bike paths. The Guide explains the disadvantages of multi-use paths; however, it could go much further in point out the dangers associated with a two-way bike path adjoining one side of the roadway. We would like to see the Guide specifically recommend against the type of sidewalk path which is separated from the roadway by a 2 to 3 foot grassy berm. Currently, the Guide is ambiguous on this point, saying that "when the distance between the edge of the roadway and the bicycle path is less than 5 feet, a suitable physical divider...may be considered." It seems that this type of divider could increase the hazards, rather than solving the safety problem.

John Forester: The whole bike path position requires complete rethinking. I believe that we must give up the idea of fast transportational bike paths except in those locations where pedestrians don't exist. Rather, we must accept the idea that nearly all paths are multi-use paths that can be safe only when used at far less than normal cycling speeds, and base our policy accordingly. Under these conditions, there is no point in designing what we formerly considered to be bike paths Multi-use paths serve a useful function and will continue to be built., However there is no point in designing these to be used as roadways. Cyclists must use them slowly, watching out for unexpected hazards at every point, and able to go fast only when they can determine by actual observation that no such hazards exist. Slow speed limits must be applied, as has been found necessary on several very well-designed paths or trails. Under these conditions, no special standard for bike paths is necessary or desirable; the traditional practices for park paths are suitable. (Note: this statement is taken from a lengthy discussion, included in the author's letter)

Dan Burden: Bicyclists are now in greater conflict with pedestrians and other trail users. More detail and definition of how to provide for bicyclists, especially with minimum center lining for curves, hills, acceptable vertical crests, and vertical sag distances need to be specified. Since landscaping has proven to be an ongoing problem, more must be said about curves and stopping sight distances, acceptable heights of shrubs, and other factors related to vegetation.

Ralph Hirsch: Bicycle/pedestrian compatibility is only mentioned in terms of sidewalks and bike pathsnot at all in context of pedestrianized or m.v.-restricted areas.

Diane Bishop: In reality, I would guess most paths are multi-use. Is it truly advisable to separate pedestrians from bicyclists, as the Guide suggests? Is there experience that it does work?

Curt Yates: Regarding off-road paths, we have also had increasing numbers of requests for assistance with greenway type bicycle paths. Discussion with local requestors frequently reveals that they have little awareness of any design standards for joint-use paths, though they typically include bicyclists as main user groups for their projects. Specific inclusion of greenway-type paths in the Guide may be warranted, with a particular focus on pathways in flood plain areas. One question related to this greenway type of request has arisen several times: are there surfaces other than asphalt which can be acceptable for bicycle travel? The section in the Guide on pavement structure begs the question, saying merely that "hard all weather surfaces are usually preferred over those of crushed aggregate, sand, clay, or stabilized earth..."

AASHTO: insert after paragraph 3: "It is important to recognize that the development of extremely wide sidewalks does not necessarily add to the safety of sidewalk bicycle travel. Wide sidewalks encourage higher-speed bicycle use and can increase potential for conflicts with motor vehicles at intersections, as well as with pedestrians and fixed objects."

Sharon Todd: Revised paragraph 5 adding emphasized items: "Using a single path for bicycles and horses... Two parallel paths within the same corridor has been found to work well."

Sharon Todd: Add the following to the last paragraph: "Where snowmobile use is not desired or when they may damage the pavement surface due to insufficient snow depth, local regulations may be required."

Peter Lagerwey: The Guide currently recommends separating bicycles and pedestrians but does not provide any guidance on how this should be accomplished. For example, if the minimum width for a two-way bicycle path is eight feet and the minimum width for a two-way pedestrian path is five feet, is it appropriate to construct 13-foot paths with a strip that designates eight feet for bikes and five feet for pedestrians? If we create two separate paths, does there need to be a five-foot separation or a 4.5 foot railing between the two paths? I think it is important that AASHTO say something on this issue because the issue of bicycle/pedestrian conflicts is receiving more attention as trails everywhere become more congested.


Return to BikePlan Source Home Page
Return to Guide Comments