Channelization and delineation are design elements that can separate directions of traffic, restrict certain movements, or direct traffic to a particular location.
Channelization and delineation alert and guide travelers safely through an intersection or along a roadway using pavement marking, curbing, and vertical devices. Channelizing and delineating devices separate directions of traffic, restrict certain vehicle movements, and/or direct traffic to a particular location.
At intersections, channelization clarifies where a driver, pedestrian, or bicyclist should be as they approach and travel through the intersection. For example, signalized intersections with multiple lanes—and, in particular, multiple turn lanes—can end up with a lot of open space within the intersection. Striping inside the intersection guides each road user through this open area.
Delineators can be used to provide similar types of guidance, like vertical delineators around a curve or small reflectors placed along guardrail to make its location more visible to motorists.
Channelization and delineation can also separate vehicles from other modes of travel, like bicycles and pedestrians. For example, a bicycle lane can be added with pavement marking alone. A buffered bicycle lane includes vertical delineators as a visual cue to motor vehicle drivers that the lane is exclusive to bikes. Pedestrian refuge islands and curb bulb-outs are types of delineation that provide a protected space for pedestrians to wait before crossing the roadway.
Roundabouts require channelization at multiple points along a motorist’s path:
- When approaching the roundabout, motorists will see a splitter island that delineates opposite directions of travel (to and from the roundabout). Agencies should use raised pavement for this splitter island, as opposed to pavement markings alone. This same splitter island should also have a crosswalk cut through it so pedestrians can cross at street level through that island.
- As the motorists enter the circulating roadway, the lane (or lanes) will be channelized to denote where they should be driving. At each potential “exit point” of the roundabout, additional channelization, using pavement marking and another splitter island, will provide positive guidance for the driver to continue from the roundabout.
Channelization and delineation can be used to restrict certain traffic movements or modes. For example, right-in/right-out-only driveways can be installed by channelizing the turns and adding an island and median barrier that disallows left turns in/out of the access point.
Using pavement marking and a raised island, a segment of roadway (e.g., a neighborhood street or central business district) can restrict motor vehicles while allowing bicycles to travel through. The channelization can be designed in such a way that emergency vehicles can either mount or straddle the island to enter the segment if needed.
When to use this strategy
Channelization and delineation make sense for roadways where additional design features are needed to guide road users, separation is needed between different transportation modes, or some traffic movements should be restricted to support safe and efficient travel.
- Reduced collision risk for active transportation modes, like bicycles and pedestrians, by separating them from motor vehicle traffic
- Increased safety for road users by providing clarity about their position on the roadway, especially when navigating intersections
- Improved traffic flow by using channelization to manage driveway access
What you need in order to implement
- Design standards and policies provide agencies with research-based guidance for implementing channelization and delineation treatments
- For certain applications, like limiting turn movements or modes, outreach efforts like one-on-one conversations or public meetings are needed to share the benefits and potential impacts with residents, businesses, and local travelers
- Basic installation equipment will be required for the installation of signage and pavement marking. In the case of more permanent installations, like curbing, more extensive construction equipment will be needed
- Channelization and delineation require significant maintenance. Pavement marking must be replaced regularly. Signs should be checked for visibility and proper placement. Vertical devices often get damaged or knocked down by motor vehicle drivers or snow plowing operations, so they must be monitored closely and repaired or replaced as needed
Agency resources needs:
- Agency crews are needed to install and maintain striping, signage, and other channelization and delineation devices
Learn more about this strategy
About key characteristics
Channelization and delineation is appropriate for all locations.
Delineation and channelization can be implemented with low-cost solutions like signage, striping, and plastic delineators.
Most treatments to channelize and delineate are small devices that do not incorporate technology.
Agencies can often install channelization and delineation without involving others. If the channelization impacts driveway access or mode separation, collaboration with those affected (e.g., adjacent residents and business owners) is needed.