Intersections naturally put users in conflict with others. The goal of intersection design is creating a space where users are mutually aware of one another, visible, and generally predictable in their actions, thus reducing overall crash rate and severity. Designers should not attempt to eliminate the number of conflicts for any given user or anticipate perfect actions.
Many vehicle-bike conflicts occur at intersections. In 2022, just over 40% of urban bike fatalities occurred at intersections.1 On many streets, large turn radii and wide lanes encourage drivers to make sweeping, fast turns.2 These design decisions increase exposure and risk for people walking and biking, reduce the safety and comfort of the bike network, and discourage people from biking.
Giving people biking, walking, and rolling a safe, accessible space and ample time to cross an intersection is paramount. Do not drop the bikeway or allow cars into the bike lane before the intersection. Continue bikeway buffers and protection all the way to the intersection.
Bikeway designs should minimize merging or weaving for people on bikes moving through the intersection; separate users in space through geometric design. Signalized intersections can also separate users in time by isolating some conflicting movements into different phases. (See Signal Phasing and Timing Strategies.)
People on bikes are often best served with dedicated approaches, protection islands, raised crossings, bike-only signal phases, or other turn management strategies. Using a combination of setbacks, separation, and forward queuing areas will create safe, comfortable intersections for a broad diversity of users.
Provide a Distinct Path of Travel through the Intersection
At signalized and unsignalized intersections and driveways, the bikeway should remain to the right (or left) of all motor vehicle lanes approaching the intersection. Avoid designs that require people on bikes to merge into motor vehicle lanes or that place bike traffic between motor vehicle lanes ahead of the intersection. These increase crash risk, particularly in higher-speed street segments that force people on bikes into drivers’ blind spots.
Constrained, buffered, and protected bike lanes can be placed to the right of through-and-right turn lanes and to the left of shared through-and-left turn lanes.
Upgrade the bikeway to a protected bike lane on the approach to signalized intersections where possible. Constrained bike lanes may be placed adjacent to turn lanes at signalized intersections with space constraints when separate signal phases are provided.3
Mixing Zones
Mixing zones may be used in constrained conditions. In a mixing zone, conflicts with turning vehicles are confined to the limited space where drivers merge into the bike lane. Mixing zones do not provide the level of comfort necessary for AA&A bikeways but also do not introduce as much risk as a dropped bike lane or a bike lane between multiple lanes of traffic. Design mixing zones to force drivers to merge ahead of the intersection and to prohibit merging within the intersection. People on bikes should have the clear right-of-way over vehicles merging. Consider phase-separating the mixed lane to improve operations and safety.
Separate the Bikeway Approaching the Intersection
Equal or greater separation should be used on the approach to intersections compared with midblock sections of a bikeway. For example, shared lanes can become constrained or protected bike lanes, and constrained or buffered bike lanes can become protected bike lanes.
Extend vertical elements, such as flexible delineator posts or curbs, to the crosswalk. If the crosswalk is set back from the intersection, continue the bike lane buffer and vertical elements on the other side of the sidewalk.
The first and last vertical separation element at an intersection or driveway should be retroreflective elements, such as flexible delineator posts or object markers.
Where motor vehicles are likely to track into the bikeway, use more robust separation on the intersection approach, such as curbs, islands, mid-height barriers, or densely-spaced flexible delineator posts.
Mark Crossbikes through the Intersection
Crossbikes, also known as bike lane extension markings, indicate that a bikeway crossing is present and help guide people on bikes through the intersection. Crossbikes may be used at all intersections and driveways, not just where turning conflicts may exist. Establish local policies and practices to ensure consistent use and widespread understanding.
Dotted white lines should be 2 ft (0.6 m) long in the direction of bike travel and 6-12 in (150-300 mm) wide. Provide 2-6 ft (0.6-1.8 m) of space between lines.
Install high-friction green surfacing in the space between each pair of dotted lines. Include a yellow dotted line down the center of the green bars for crossbikes with two-way bike operations.4
Elephant’s feet markings offer increased visibility over typical 6 in (150 mm) markings alone. Elephant’s feet are square markings up to 24 in (600 mm) on each side with equal spacing between markings and can be white squares or white squares at the ends of green bars.7
Some jurisdictions have found value in using bike symbols or arrow markings in the crossbike. With bidirectional crossbikes, such markings are placed in both directions. Using shared lane markings or chevrons within the crossbike is experimental under the U.S. MUTCD.
Do not use crosswalk markings as part of the crossbike; these must be separate.
Legal Right for People on Bikes to Use a Crosswalk
Bikeways may lead to a traditional crosswalk, often on shared use paths and in constrained situations. Confirm that people on bikes have the legal right to use crosswalks in state or provincial traffic laws or local ordinances. Most state vehicle codes do not address the topic of bikes in crosswalks at uncontrolled intersections. Depending on relevant laws, the following strategies may give people on bikes the legal right-of-way at a crossing:
- Install distinct crossbike markings alongside a crosswalk
- Adopt a city ordinance or regulation providing for bicycle use of crosswalks
- Partner with legislators to update state or provincial laws
- Install stop signs, full signals, or red indications appropriate for the roadway context (See Stop Controls and Red Indications.)
Credit: Jeremy Menzies, San Francisco Municipal Transportation Agency
- NACTO analysis of NHTSA FARS data showed that in 2022 there were 890 total pedalcyclist fatalities on non-interstate urban roads, of which 368 occurred at an intersection.
National Highway Traffic Safety Administration. “Fatality and Injury Reporting System Tool.” https://cdan.dot.gov/query. ↩︎ - Fitzpatrick, Kay, and William Snyder. Turn Speeds and Crashes Within Right-turn Lanes. Texas Transportation Institute, 2004. https://static.tti.tamu.edu/tti.tamu.edu/documents/0-4365-4.pdf. ↩︎
- “A through bicycle lane may be positioned to the right of a right turn only lane or to the left of a left turn only lane provided that the bicycle lane is controlled by a traffic signal that displays bicycle signal indications (see Chapter 4H).”
Federal Highway Administration. Manual on Uniform Traffic Control Devices, 11th Edition. USDOT, 2023: Section 9E.02. https://mutcd.fhwa.dot.gov/pdfs/11th_Edition/part9.pdf. ↩︎ - Federal Highway Administration. Manual on Uniform Traffic Control Devices, 11th Edition. USDOT, 2023: Section 9E.03. https://mutcd.fhwa.dot.gov/pdfs/11th_Edition/part9.pdf. ↩︎
- Transportation Association of Canada. Manual of Uniform Traffic Control Devices for Canada, 6th Edition. TAC, 2021. https://www.tac-atc.ca/en/publications/ptm-mutcdc21-e ↩︎
- Federal Highway Administration. Manual on Uniform Traffic Control Devices, 11th Edition. USDOT, 2023: Section 9E.04. https://mutcd.fhwa.dot.gov/pdfs/11th_Edition/part9.pdf. ↩︎
- Transportation Association of Canada. Manual of Uniform Traffic Control Devices for Canada, 6th Edition. TAC, 2021: Section C7.1.6. https://www.tac-atc.ca/en/publications/ptm-mutcdc21-e. ↩︎