City of Kenmore Traffic Calming Program Frequently Asked Questions

The Institute of Transportation Engineers defines traffic calming as the combination of measures that reduce the negative effects of motor vehicle use, alter driver behavior, and improve conditions for non-motorized street users. Traffic calming consists of physical design and other measures put in place on existing roads to reduce vehicle speeds and improve safety for pedestrians and cyclists. For example, vertical deflections (speed humps, speed tables, and raised intersections), horizontal shifts, and roadway narrowing are intended to reduce speed and enhance the street environment for non-motorists. Closures that obstruct traffic movements in one or more directions, such as median barriers, are intended to reduce cut-through traffic. Traffic calming measures can be implemented at an intersection, street, neighborhood, or area-wide level.

The City of Kenmore developed the “Policies and Procedures for the City of Kenmore Traffic Calming and Speed Management Program” document in February of 2023 for use in decision making on traffic calming device implementation.  The 85^th percentile speed on NE Arrowhead Drive exceeds the threshold to warrant traffic calming devices to reduce speed and increase safety of the corridor. In other words, less than 16% of drivers are traveling at or below the speed limit, and furthermore over 40% of drivers are exceeding the speed limit by 5 mph or more. The City of Kenmore's traffic calming policy is to take measures to reduce travel speeds any time more than 15% of drivers are exceeding the speed limit by 5 mph or more.

Traffic calming treatments which may be considered include but are not limited to the following:

• Chicanes, Curb Extensions / Bulb-outs, or Pinch-Points
• Curve or Intersection Corner Radius Reduction
• Lane Width Reduction
• Medians or Splitter Islands
• Reduction in Number of Lanes or Road Diets
• Signing and Pavement Marking Changes
• Speed Feedback Signs
• Speed Humps, Speed Tables, Speed Cushions, Raised Crosswalks, or Raised Intersections
• Street Narrowing and / or Roadside Features
• Street Parking Reconfiguration
• Through-Street Access Restriction or Closure
• Traffic Circles or Roundabouts

Things you drive over are those which extend vertically from the road surface to slow traffic, for example speed humps. Things you drive around slow traffic by extending horizontally, such as curb bump outs or chicanes, and create the perception of friction for traffic passing through the area.

Staff from the City of Kenmore Police Department and the Northshore Fire Department are involved in this process. The plans for the proposed traffic calming devices are shared with Police and Fire representatives for comment, and they are invited to attend the meetings. Typically, police and fire representatives report that emergency response time is increased by a few seconds (approximately 2-10 seconds) as police and fire must slow down at device locations. Impacts to response time must be weighed against overall safety improvements from traffic calming.

The street would continue to receive winter maintenance at the current rate. City of Kenmore Public Works Operations staff handle snow plowing in areas throughout the city where traffic calming devices such as speed humps and chicanes have been installed. The location of devices that you drive over or around are clearly marked so that maintenance crews are aware.

We do not expect any change in drainage pattern due to traffic calming device installation.

We do not typically hear complaints regarding impacts to school buses, but they do have to slow down the same as other traffic when passing over speed humps or through traffic calming devices. 

Traffic calming devices should not deter cyclists, if they are traveling under 25mph.

Institute of Transportation Engineers (ITE)

Each address within the project mailing area (residents and property owners) receives a final plan and polling opportunity to determine community support. Respondents indicate support or opposition for the plan by marking ‘yes’ or ‘no.’ Greater than 50% of returned final polls must indicate support (‘yes’) for the final plan to move forward for City Council approval to construct.