Pedestrian Safety Guide and Countermeasure Selection System


Recommended design for right-turn slip lane.

A well-designed right-turn slip-lane is an effective mitigation strategy when intersection radii reduction is not an option.


Shaper angles of slip lanes are important to slow cars and increase visibility.


Source: Designing for Pedestrian Safety A well-designed right turn slip lane at a complex intersection.
Source: Designing for Pedestrian Safety


Improved Right-Turn Slip-Lane Design

Well-designed right-turn slip lanes include several key features:
• The island (sometimes referred to as the “pork chop”) that forms the channelized right-turn lane is raised and large enough to accommodate waiting pedestrians and accessibility features, such as curb ramps or cut-throughs).
• As they enter the right-turn lane, drivers can easily see pedestrians crossing or about to cross the right-turn lane, and have enough space to stop completely once a pedestrian is spotted.
• The right-turn lane is as narrow as possible while still enabling the design vehicle to make the turn. Edge lines and with cross-hatching can be used to narrow the perceived width of the lane while still accommodating larger vehicles.
• The crosswalk is oriented at a 90 degree angle to the right-turn lane to optimize sight lines, and is positioned one car length back from the intersecting roadway to allow drivers to move forward and wait for a gap in oncoming traffic after clearing the crosswalk.
• The visibility of the crosswalk to drivers is further enhanced through the use of high-visibility crosswalk striping, flashing beacons, and/or signage. Raised crosswalks may also be used to force motorists to slow down.
• The angle at which the right-turn lane intersects the cross street is relatively low (e.g., closer to 110 percent, rather than 140 percent). This feature lowers motor vehicle speeds and makes it easier for drivers to see oncoming traffic.
• Good design can be recognized by the long “tail” on the island (i.e. long tail means slower turning speed; short tail means faster turning speed – see illustrations below.
• Acceleration lanes are not provided where the right-turn lane intersects the cross street. Acceleration lanes enable drivers to navigate the channelized right-turn lane at higher speeds than would be possible if drivers had to yield to cross street traffic.
• The needs of visually impaired pedestrians are considered as part of the design. For example, rumble strips placed in the right-turn lane can help visually impaired pedestrians judge whether drivers are yielding as they approach the crosswalk.
• Active warning beacons may be desirable in locations where there are high traffic volumes and vehicle speeds.


Well-designed right-turn slip lanes slow turning vehicles, allow drivers and pedestrians to easily see each other, reduce pedestrian exposure in the roadway, reduce the complexity of an intersection by breaking it into manageable parts, and allow drivers to see oncoming traffic as they merge into the receiving roadway. Right-turn slip lanes can be a detrimental to pedestrian safety when they allow motorists to maintain high speeds through the turn, do not optimize sight lines to the crosswalk, and do not reduce the crossing distance for pedestrians.


• Right-turn slip lanes are most appropriate at signalized intersections with higher volumes of right-turning vehicles or with geometrics (e.g., skewed) that make right turns infeasible for the design vehicle without substantially increasing pedestrian crossing distances.
• In some states, the slip lane must be stop-controlled.

Estimated Cost

Costs may vary substantially, depending on a variety of factors. For more information, see references 1, 12, 13, 14, and 15.

Case Studies