Intersection Treatments and Design Elements

Intersection Treatments

The following treatments should be considered at intersections to improve the safety of bicyclists and/or pedestrians at conflict points. The treatments listed below may not reflect all possible options for improving safety at intersections. Therefore, guidance published by the Indiana Design Manual and/or organizations such as the National Association of City Transportation Officials (NACTO) and the Federal Highway Administration should be referenced.

Through Bicycle Lanes

Intersections with dedicated turn lanes can be challenging for bicyclists traveling in a conventional or buffered bicycle lane. Therefore, it is important to provide bicyclists with the opportunity to position themselves in a way that avoids conflicts with turning vehicles. The through bicycle lane design leads to more predictable bicyclist and motorist travel movements and positions bicyclists to the left of right turning vehicles. Similar to the lateral shift design on the adjacent page, in this configuration potential conflicts between right-turning vehicles and through bicyclists occur before the intersection. This treatment is effective for intersections where a separate bicycle signal and signal phasing is not feasible as bicyclists can proceed in the same signal phase as through and rightturning vehicles.

This design gives bicyclists priority and allows them to continue straight to the intersection. The dashed lines alert motorists to expect bicyclists and to yield to bicyclists as they make their way to the intersection. The dashed lines also signify to motorists an appropriate location to safely merge across the bicycle lane into the right turn lane.

Lateral Shift

A lateral shift moves bicyclists to the left of the motor vehicle right turn lane before vehicles can merge to the right. This places responsibility of yielding on drivers turning right, and brings bicyclists into a highly visible position. In the lateral shift configuration, potential conflicts between right-turning vehicles and through bicyclists occur before the intersection. A lateral shift treatment is effective for intersections where a separate bicycle signal and signal phasing is not feasible as bicyclists can proceed in the same signal phase as through and right-turning vehicles. This design is typically achieved by removing a protected cycle track barrier or parking lane and shifting the bicycle facility closer to the adjacent motor vehicle lane to position the bicyclist to cross the intersection safely.

Source: Separated Bike Lane Planning and Design Guide

The following considerations apply to a lateral shift:

Provide minimum queue storage length for motor vehicles, based on right-turn volumes and cycle length.

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. Include “Begin Right Turn Lane Yield to Bikes,” MUTCD R4-4, at the end of parking restrictions or the cycle track physical barrier.

. Provide between 20-40 feet of length to shift the bicycle facility closer to motor vehicle traffic.

The bicycle facility should terminate as close to the intersection and provide as small of a merging area as feasible. This encourages motorists to make slow and deliberate turning movements into the right turn lane. The length of the merge area should be 60 feet for roads with a speed of 30mph or less or 90 feet for roads with a speed greater than 30mph.

. Provide an optional narrow buffer with vertical delineators between the travel lanes and bicycle facility to increase comfort for bicyclists and slow driver turning speeds.

. Where a cycle track uses parked cars within the buffer zone, parking must be prohibited at the start of the transition.

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. The lateral shift can be paired with intersection crossing markings, such as green pavement, to raise awareness of conflict points.

Mixing Zone

A mixing zone is an area where bicyclists and right-turning motor vehicles merge into one travel lane approaching an intersection. Mixing zones can provide the best option on roadways without on-street parking and/or with limited right-of-way where the roadway width cannot accommodate both a bicycle lane and a right turn lane at the intersection. In this configuration, shared lane markings help guide bicyclists to the turning lane, which tends to have lower speed traffic than the adjacent through lane. In both examples below, include “Begin Right Turn Lane Yield to Bikes,” MUTCD R4-4 before the mixing zone.

PROTECTED INTERSECTIONS (AND BEND OUTS)

At protected intersections, the bicycle facility is set back from the parallel vehicle travel lane and bicyclists are provided with a dedicated path through the intersection. This design includes corner refuge islands, marked bicycle crossings parallel to pedestrian crosswalks, and two-stage left turns for bicyclists. The protected intersection maximizes user comfort within the intersection and promotes a high rate of motorists yielding to bicyclists. This intersection treatment positions bicyclists away from the intersection, allowing vehicles to complete turning movements before interacting with and yielding to bicyclists. It also provides space for a vehicle to yield to crossing bicycles without blocking through motor vehicle traffic. This design also provides the opportunity for a pedestrian refuge between the bicycle facility crossing and the street crossing. Protected intersections are most commonly found on streets with buffered bicycle lanes and cycle tracks protected by wide buffers or on-street parking.

Protected intersections provide a greater comfort level than other alternatives, accommodating the Interested but Concerned bicycle user group. This design helps reduce conflicts between right-turning motorists and bicyclists by reducing turning speeds and providing a forward stop bar for bicycles.

Protected intersections include “bend outs,” which are described below.

The following considerations apply to protected intersections and bend outs:

. A “Turning Vehicles Yield to Bikes” sign may be placed at the intersection. .

The bicycle facility and crosswalk may be raised to sidewalk level through the intersection, providing a traffic calming effect and increasing visibility of bicyclists.

Wayfinding and directional signage may be needed to direct bicyclists through the intersection. .

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Colored pavement may be used within the corner refuge area to clarify use by bicyclists and discourage use by pedestrians.

Protected signal phasing may provide additional comfort for less confident bicyclists. .

Retrofit implementation can include lower costs if existing curbs and drainage are maintained. Inexpensive materials, such as concrete planters and bollards, can be used.

The bend out configuration can also be applied to shared use paths at signalized and unsignalized intersections. By increasing the offset distance between the shared use path crossing and the primary intersection, motorists turning from the parallel roadway are better positioned to see bicyclists at the crossing. This offset distance also creates a space for right-turning vehicles to yield and wait for through moving bicyclists and pedestrians. A larger offset allows motorists exiting a driveway or side street onto a primary roadway to separate yielding actions, yielding first to shared use path users and again, after pulling forward, to traffic on the primary roadway. The Dutch CROW Manual recommends 16-23 feet of setback from the curb line of the parallel street.

Protected Bicycle Signal Phase

The safety of bicycle facility crossings at signalized intersections can be increased by using a protected bicycle signal phase, which reduces conflicts with motor vehicles by separating bicycle movements from any conflicting motor vehicle movements. Fully separated signal phases for bicycles and vehicles provide a green bicycle phase and pedestrian walk signal while motor vehicles have a red arrow, prohibiting right turns. This phase is followed by a motor vehicle turning phase with a red bicycle signal.

Bicycle signals are traditional three lens signal heads with green, yellow, and red bicycle stenciled lenses. The separated bicycle signal phase is typically used when increased conflict points warrant protected operation for bicyclists.

The bicycle signal must be timed so that bicyclists moving on a green or yellow signal of a bicycle signal will not be in conflict with any simultaneous motor vehicle movement at the signalized intersection. Right turn on red should be prohibited in locations where the operation would conflict with a green bicycle signal indication.

Bicycles at signalized intersections should be able to trigger signals and safely maneuver through the intersection. Bicycle detection and actuation systems include user-activated buttons mounted on a pole, loop detectors that trigger a change in the traffic signal when a bicycle is detected, and video detection cameras that use digital image processing to detect a change in the image at a location.

Bike Boxes

A bike box is a designated area at the head of a traffic lane at a signalized intersection that provides bicyclists using a conventional bicycle lane, buffered bicycle lane, and some cycle tracks with a safe and visible way to get ahead of queuing traffic during a red light. Bike boxes increase visibility of bicyclists and help prevent conflicts with rightturning vehicles at the beginning of a green light signal. Bike boxes can also facilitate the positioning of left turning bicyclists when the bike box extends across the entire intersection. Bike boxes are typically 10 to 16 feet deep.

Two Stage Bicycle Turn Boxes

The two stage bicycle turn box designates an area at an intersection for bicyclists to wait for traffic to clear before making a left turn at multi-lane signalized intersections from a right side cycle track or bicycle lane. Two stage bicycle turn boxes can also be used at unsignalized intersections to simplify turns from a bicycle lane or cycle track onto a neighborhood bicycle route, for example.

With the two stage bicycle turn box, bicyclists cross the intersection within the bicycle lane, buffered bicycle lane, or cycle track, stop within the turn box, reorient themselves to the cross street, and wait for the signal for the cross street to proceed. This design eliminates the need for bicyclists to merge across travel lanes.

The two stage bicycle turn box is essential in protected intersections. Because protected intersections prevent bicyclists from merging into traffic to make left turns, the two stage bicycle turn box provides the opportunity to make such turns.

The following considerations apply to two stage bicycle turn boxes:

A two stage bicycle turn box must be located outside of the path of through and turning traffic. Typically, this protected area is within an on-street parking area or between the bicycle facility and the pedestrian crossing.

. A two stage bicycle turn box must include a bicycle symbol oriented in the direction in which bicyclists enter the box, along with an arrow showing the direction of the turn.

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. If limited space or right-of-way prevents the placement of a two stage bicycle turn box within a protected location, the turn box may be located behind the pedestrian crosswalk. This configuration should only be considered in locations where pedestrian volumes are low because bicyclists will need to yield to pedestrians in the crosswalk before entering the turn box.

Colored pavement should be used to make the turn box more visible to roadway users. .

A “No Turn on Red” sign must be installed to prevent vehicles from entering the turn box to make a right turn. .

As of July 2017, communities wishing to use two stage bicycle turn boxes must request approval under FHWA Interim Approval 20. .