Right-turn slip lanes at urban intersections must be designed to accommodate both motorists and pedestrians. Considerations should be given for crosswalk compliance by motorists and pedestrians, design vehicle accommodations, speed of turning traffic, provisions of auxiliary lanes, adjacent land uses, visibility of anticipated pedestrian traffic, and acuity of the cross-street traffic from the right turn drivers’ perspective. In areas where pedestrian activity is moderate to high, raised crosswalks may be installed to slow turning motorists and improve their likelihood of stopping and yielding to crossing pedestrians. A raised crosswalk may in some instances have the benefit of reducing the length of a required ramp on the pedestrian island. However, raised crosswalks are not recommended along highspeed facilities. If the slip lane is a multilane crossing for pedestrians, one or more of the following must be provided: a traffic signal, pedestrian hybrid beacon, a rectangular rapid flashing beacon, and/or a raised crosswalk.

The following recommendations address these considerations and are reflected in the configurations shown in (with a deceleration lane) and (without a deceleration lane).

Angle of Entry -

The angle of entry between the slip lane and the cross street is recommended to be 70 degrees. This configuration slows motorists, reduces the head-turning movement to look for gaps in oncoming traffic, and makes it easier for motorists to identify crossing pedestrians. If an angle of 70 degrees is not achievable due to constraints, reduce it accordingly.

The minimum recommended angle is 55 degrees.

Curb Radii and Curb-to-Curb (throat) Width -

Most traffic on urban streets is expected to be passenger cars and single-unit trucks. However, to accommodate the turning movement of larger vehicles, the curb radius, and curb-to-curb width can be designed for a larger design vehicle while striped to delineate the path for a smaller vehicle. For guidance on curb radii design for different vehicle classes, see . See below for lane markings.

Channelizing Island -

Islands are recommended to have a minimum side length of 15-ft, excluding the corner radii, refer to . Channelizing islands should be offset from the edge of the traveled way to reduce their vulnerability. A 12-ft side length may be used in special circumstances, where the 15-ft minimum cannot be met due to highly constrained conditions. See for design guidance on curb offset and tapering. In the presence of a bicycle lane, which serves as a separation between the curb and the travel lane, curbs need not be offset. Additional information on appropriate curb type and design, see and .

Pedestrian accommodations are a central component of the design. The pedestrian access routes across channelizing islands are sometimes set at the top of curb elevation using a series of curb ramps and landings ( ).

Smaller channelizing islands may not have adequate space to provide the necessary curb ramps, so the pedestrian access route can be cut through the island flush with the gutter grades of the roadway ( ).

This option is preferred

since it is easier for some pedestrians to navigate, especially those with vision disabilities and does provide some wayfinding benefits. However, it can also collect water and debris, increasing maintenance needs.

A third option is to raise the accessible route to at least 2-in above the roadway gutter grade ( ). This solution helps reduce the maintenance required for cut-through islands and still provides some wayfinding clues. If a raised crosswalk is used, this would also result in a reduction in the length of the needed ramp for the options depicted in and .

Provide flared sides where the pedestrian circulation path crosses the curb ramp as shown in and . Flared sides shall be sloped at 10 percent maximum, measured parallel to the curb. Curb returns may be used only where pedestrians would not normally walk across the ramp because the adjacent surface is planted, substantially obstructed, or otherwise protected.

All components of the accessible route should be constructed at a minimum 5-ft width to provide adequate room for pedestrian passage.

If partial cut-through sections are used, a 10 percent flare and rounded corners along the pedestrian pathway should be used to provide better wheelchair mobility.

Deceleration Lane -

These lanes allow motorists to decrease speed before negotiating a turn while separated from through traffic. This separation helps pedestrians identify right-turning vehicles. Refer to Number, Location, and Spacing of Access Connections in Chapter 2 of the for volume thresholds for installing deceleration lanes. See for design recommendations for deceleration lanes.

If conditions do not necessitate a deceleration lane or ROW is restricted, consideration should be given to using a taper, see . See and for sample right-turn slip lane designs with and without a deceleration lane.

Acceleration Lane -

Acceleration lanes typically are not used on urban streets since:

Accordingly, acceleration lanes are not advisable where pedestrian activity is anticipated.

Drainage -

Any necessary inlets should be designed and placed on the upstream side of the crosswalk at a location that prevents—or limits to the extent practical—the spread of water into the crosswalk. Cut-through access should be situated to minimize paths for water flow. Avoid placing drainage low points at or near the ADA curb ramps.

Lighting -

Intersections with channelization should be illuminated. Lighting helps motorists identify islands, diverge and merge locations, turning roadways, and pedestrian crossings. Adequate lighting at urban intersections, including illumination of crossing locations, is important—particularly where pedestrian activity is expected at night. Refer to Chapter 6, of TxDOT’s for pole placement guidelines.

Apparatus and Pole Placement -

ITS equipment, signal, utility poles, and apparatuses should be outside of paved pedestrian walkways and landing areas. Refer to the and TxDOT standard drawings for guidance on mounting heights and limits on object protrusion into pedestrian facilities. When pedestrian facilities are not initially installed, care should be taken to avoid the placement of apparatuses and poles in anticipated or planned locations of future pedestrian walkways and landing areas.

Crosswalk Location -

Crosswalks should be placed toward the middle of the channelized island with a

minimum of 20-ft between the crosswalk and yield line

for the intersecting street as shown in and . Crosswalks may be placed near the beginning of the channelized island if conditions do not permit a centralized location, or it is more conducive to the natural pathway of pedestrians. When the crossing is located at the beginning of the channelized island, care should be taken to place it such that there is enough space available at the ramp location for an appropriate landing area. Placement of the crosswalk near the end of the turning roadway is not recommended as motorists are expected to encroach on the crosswalk as they yield to oncoming traffic. Also, motorists arriving at the downstream end of the turning roadway typically focus their attention on cross-street traffic rather than crossing pedestrians.

Crosswalk Orientation -

The pedestrian crosswalk should be oriented perpendicular to the turning roadway to shorten the crossing distance for pedestrians and to place approaching vehicles in the periphery of pedestrians.

Crosswalk Markings -

At locations where pedestrian activity is anticipated, a “High-Visibility Longitudinal Crosswalk” pattern is recommended to delineate the crossing location. The transverse markings facilitate wayfinding for visually impaired pedestrians and the inclusion of longitudinal lines provides additional visibility for approaching motorists. Alternatively, longitudinal markings alone can be installed to define the crossing path. Refer to the for further guidance on the installation of crosswalk markings.

Signage and Pavement Markings -

Yield signs are typically the appropriate traffic control devices for right-turn slip lanes at urban intersections. The yield line is used alongside the yield sign to draw attention to the need to yield to cross-street traffic. Refer to the and for guidance on yield sign and yield line placement. Where there is high pedestrian activity or when driver compliance is in question, additional signing may be used (see ).

The travel lane should be striped to a minimum of 10-ft in width (11-ft typical) to accommodate a passenger vehicle, and the void area (shoulder) may be delineated by diagonal lines as shown in and . A raised truck apron may also be considered in the void area to further enhance the channelization of passenger vehicles.

Bicycle Lane -

When a bicycle lane is used, it should be striped appropriately to define ROW and shared spaces. Refer to Chapter 18, the , as shown in the , and as detailed on for bicycle lanes. Bicyclists intending to make a right turn can use the right-turn lane/turning roadway and operate like a motorized vehicle.