Separated Bike Lane Planning and Design Guide

Chapter 5: Menu of Design Recommendations

Design Recommendations

Four Step Design Process

The separated bike lane design process can be categorized into four general categories - Directional and Width Characteristics, Forms of Separation, Midblock Considerations, and Intersection Considerations. These categories form the basis of a four-step design process where the decisions within each step inform future design decisions, resulting in an iterative design process based on available street width, transportation priorities, and other project goals. This chapter groups the design process into these four categories and provides flexible design options to best meet local conditions and the community's goals.

When designing these newer types of facilities, it is important to document the numerous decisions made throughout the design process. Documentation should demonstrate that the final design was developed based on the best available data, good engineering judgment, and sound design principles.

STEP 1: Establish Directional and Width Criteria

• The decision of one-way and two-way separated bike lanes should be based on traffic lane configurations, turning movement conflicts, parking requirements, and surrounding bicycle route network options and destinations.
• Width considerations include expected bicycle volumes, required buffer width, and maintenance requirements.
• Alignment decisions for running the separated bike lane on the right-side, left-side, or in the center of the road, include transit stop conflicts, intersection and driveway conflicts, locations of destinations, and parking placement.

STEP 2: Select Forms of Separation

• Separation type decisions should be based on the presence of on-street parking, street width, cost, aesthetics, maintenance, motorized traffic volumes and speeds.

STEP 3: Identify Midblock Design Challenges AND Solutions

• There are several potential conflicts that may occur at midblock locations along a separated bike lane.
• Transit stops occurring on the same side of the street as the separated bike lane present a challenge due to interactions among cyclists, transit vehicles, and those accessing transit stops.
• Locating accessible parking spaces may require additional design adjustments.
• Loading zones should be well-located and designed to minimize conflicts.
• Driveways present concerns due to challenges with sight distance and driver expectations
  that can be minimized through design treatments and driveway consolidation.

STEP 4: Develop Intersection Design

• Intersection design should focus on the safety of all users with additional consideration
  on delay, queuing, user expectations, motorized traffic volumes and speeds.
• Sufficient sight distance for all street users at intersection approaches should
  be provided.
• Designs should protect or provide safe interactions between separated bike lane users and conflicting turning movements.
• Signs and markings should be included to appropriately guide and prompt safe behaviors through intersections.

Design Recommendations: Flexibility in the Planning and Design Process

The designs presented in this chapter are based on current design guidance and the state of the practice and are intended to be a starting point for a flexible design process that takes into account site conditions, context, and continually evolving design resources. The graphic below highlights the key elements of a successful design process, but the order and exact execution of the steps are flexible. Evaluation and design are iterative processes, with designs evolving as municipalities evaluate how a facility is functioning.

Figure 7

Step 1: Directional and Width Characteristics

The selection of separated bike lane width and directional characteristics depends on a combination of factors that are most often determined by the existing street and surrounding network characteristics. The most critical considerations are to reduce conflicts with turning vehicles, provide sufficient width for safe operations and ease of maintenance, and ensure predictable behavior by the street users.

Direction and Width: One-Way Separated Bike Lane on a One-Way Street

A one-way separated bike lane on a one-way street is the least complicated design. This type of design can most easily be implemented on existing streets through the conversion of a motor vehicle lane or removal of on-street parking. Another advantage of this type of facility is the ability to provide a reasonable signal progression for cyclists, improving travel time and signal compliance. One potential complication of this design may be wrong-way riding by bicyclists. This can occur if there are no suitable and attractive bicycle routes (such as a parallel facility) near this separated bike lane.

1. One-way separated bike lanes should have a minimum width of 5 ft. Wider separated bike lanes provide additional comfort and space for bicyclists and should be considered where a high volume of bicyclists is expected. Widths of 7 ft and greater are preferred as they allow for passing or side-by-side riding. Additional care should be taken with wider lanes such that the separated bike lane is not mistaken for an additional motor vehicle lane.
2. Total clear width between the curb face and vertical element should be at least the fleet maintenance (sweeping or snowplow) vehicle width. Widths (inclusive of the gutter pan and to the vertical buffer element) narrower than 7 ft will often require specialized equipment. Consultation with a Public Works department is recommended during the planning process.
3. A minimum 3 ft buffer should be used adjacent to parking. For further guidance on buffer selection and installation, see page 83.
4. For further guidance on typical signs and markings for separated bike lanes, see page 127.

One way Separated Bike Lane on a One-Way Street (Left-Side Running)

Long Beach, CA, has installed left-side, one-way separated
bike lanes along a pair of one-way streets downtown.
(Source: City of Long Beach)

Consider a left-side running separated bike lane under the following conditions:

• The corridor includes a high frequency transit route resulting in potential conflicts with transit vehicles, stops, and transit riders.
• There are fewer driveways, intersections, or other conflicts on the left-side of the street.
• The most likely destinations for bicyclists are on the left-side of the street.
• On-street parking is located on the right-side of the street.

Direction and Width: One-Way Separated Bike Lane on a Two-Way Street

Providing one-way separated bike lanes on each side of a two-way street creates a predictable design for managing user expectations. Typically, each separated bike lane will run to the outside of the travel lanes in a design similar to a one-way separated bike lane on a one-way street. A potential challenge with this design is it takes up more roadway space compared to the alternatives of providing a two-way separated bike lane or developing alternate corridors for directional travel.

(Not to Scale)

1. Bike symbols should be placed periodically in the lane.
2. Drainage grates and gutter seams should generally not be included in the usable width.
3. For further guidance on buffer selection and installation, see page 83.
4. For further guidance on typical signs and markings for separated bike lanes, see page 127.

Central Median Alternative

An alternative design places separated bike lanes adjacent to a median. This design can be considered when there are significant conflicts due to turning movements, transit activity, or other conflicting curbside uses. Depending on the width of the median, this design may result in intersection design challenges, particularly in how bicyclist right- and left-turns are made.

Figure 10

Direction and Width: Two-Way Separated Bike Lane on Right-Side of One-Way Street (2 Lanes)

Providing a two-way separated bike lane on a one-way street may be desirable under certain circumstances. This design couples a separated bike lane with a contraflow bike lane in order to route bicyclists in the most direct or desirable way given the street network and destinations. However, this design can create some challenges for roadway user expectancy at intersections and driveways, which could be mitigated by signage suggesting to look both ways for pedestrians. Additionally, certain intersection designs are not possible.

Left-Side Running Alternative

Consider a left-side running separated bike lane under the following conditions:

• The corridor includes a high frequency transit route resulting in potential conflicts with transit vehicles, stops, and transit riders.
• There are fewer driveways, intersections, or other conflicts on the left-side of the street.
• The most likely destinations for bicyclists are on the left side of the street.
• On-street parking is located on the right side of the street.

Direction and Width: Two-Way Separated Bike Lane on Right-Side of Two-Way Street

Providing a two-way separated bike lane on a two-way street may be desirable under certain circumstances such as minimizing conflicts on high frequency transit corridors or along corridors with a higher number of intersections or driveways on one side of the street (such as along a waterfront). This design does, however, create some challenges for roadway user expectancy at intersections and driveways. Additionally, the design limits intersection design options.

Center Orientation Alternative

An alternative design places a two-way separated bike lane in the center of the street. This design is uncommon and can be considered when there are significant conflicts due to turning movements, transit activity, or other conflicting curbside uses. Depending on the width of the roadway and the amount of space that can be allocated to the separated bike lane and buffer, this design may result in intersection design challenges, particularly on how bicyclist right- and left-turns are made.