Traffic Calming Guidelines

PURPOSE: Residents throughout the City of Annapolis, as well as those in neighboring jurisdictions, are often concerned about what they perceive as undesirable high travel speeds in residential areas. This speeding contributes to a sense of uneasiness and in many cases, presents unnecessary hazards to residents, pedestrians, and motorists. Although Police Department enforcement may be temporarily effective in lowering speeds somewhat, our experience indicates that longer-term solutions require changing the behavior of motorists. This may be done by effectively reminding drivers to slow down, changing travel patterns, or instituting physical changes which limit the speed at which a motorist may comfortably drive.

These guidelines are intended to provide a general overview of the process which the City of Annapolis uses to address traffic concerns in residential areas. They are not rules and regulations of the Director of Public Works. These Guidelines will be revised and fined-tuned in the future as additional experience is gained.

PROCESS: The process of dealing with a community is as important as the actual plans which arise from the process. Communities which feel that their concerns have not been adequately addressed may oppose plans even though they are demonstrably beneficial. Failure to correctly define and document problems may lead to recommendations that do not address the actual cause of concern.

The Traffic Control and Maintenance Division will address any concern (within its area of responsibility) in a professional and timely manner. In most cases, other than routine repairs and slight modifications to traffic controls, it is helpful to deal with representatives of all groups and individuals who are affected by the problem or who may be impacted by proposed solutions. By the same token, large public meetings do not allow for effective communication and discussion. When individual citizens contact the Division with complaints that impact more than just themselves, they should be encouraged to bring their concern to us through an appropriate community organization. Ideally, we would like to work with a group of 5 to 12 persons representing the affected area(s) to study the problem and propose solutions. This might be the Board of Directors of the community association, a public works or safety committee of an association, or an ad hoc committee dedicated to dealing with the specific issue(s). If the citizen who contacts the Division individually is unable or unwilling to work through such a group, Traffic will attempt to make appropriate contacts before or after conducting studies and developing recommendations. Unless the City determines that immediate action is warranted, no major changes in traffic patterns or control will be made without some type of public involvement or notification. (See also the paragraph entitled COMMUNITY INPUT.)

As noted, the study process must be comprehensive and fair. By working with a group of citizens, both of these goals can be achieved. The citizens can provide valuable input into defining the problems and what "the community wants", and their participation in the process can serve to reassure the rest of the community that their concerns were addressed. It is easier to implement changes if members of the affected community have been a part of the process and will vouch for its integrity. Working with a small group, the process should include the following steps:

  1. Define the Problem(s): The group is asked to brainstorm a list of concerns (relating to traffic issues). No one is allowed to dismiss anyone else's concerns as not valid or unimportant. Very often, the community members themselves do not agree on what is wrong. This step makes certain that all of the relevant issues are on the table.
  2. Document the Problem(s): The City will collect whatever data is necessary to document the scope of the problem; for example, how many cut-through cars are there? how fast are they going? This data sometimes shows that there is a perception problem, not an actual problem. The documentation may lead to a redefining of the problem.
  3. Define Desired Results: Given the actual performance of the roadways, the community is asked to identify what they would like the results to be; how will we know if we have successfully solved the problems? Try to develop goals that can be measured in terms of the data collected earlier.
  4. Define Constraints: There may be certain conditions that the community (or City) insists must be met. Examples might include a desire to maintain on-street parking, maintain access to several collector routes, the need to meet the standards of the Manual on Uniform Traffic Control Devices, etc. The constraints may lead to a further redefinition of the problems.
  5. Develop Options: Using the information gathered thus far, the City will develop one or more options for consideration. The analysis should attempt to identify the benefits and impacts of each action so that the community understands all of the ramifications. Where there are undesirable impacts, the City will attempt to identify ways to mitigate those impacts.
  6. Decide on a Plan: Working together, the committee and the City consider the options. They may decide to recommend one, make modifications, or once again redefine the problem. They may decide that the solutions are worse than the problems, and therefore decide to take no action. This is a valid conclusion so long as all options have gotten fair consideration and there is no overwhelming safety problem that demands City attention.
  7. Develop Community Consent: The committee (including the City staff) will report back to the larger community to present its findings and recommendations. The citizen members of the committee can vouch for the integrity of the process, making it easier to reach agreement. On occasion, City staff may also need to obtain approval at the Department or Administration level. Implementation of recommendations will typically require significant community support, in the form of a recommendation by the community association and substantial support of those directly affected by the problem(s) and/or proposed solution(s). (See also the paragraph entitled COMMUNITY INPUT.)
  8. Do It: The plan is then implemented.
  9. Document the Results: Were the desired results achieved? Should the plan be modified? Should the problem be redefined? The results of this step may lead to closing the project, making a temporary installation permanent, modifying of actions, or beginning the process over again. In the absence of a serious traffic safety issue which requires City action, we will consider the matter closed once the community is satisfied with the results.

TECHNIQUES: There are a variety of techniques available for use in slowing or diverting traffic. These are described briefly below:

Educational Measures: In many cases, it is the residents themselves who are the primary violators of the posted speed limit. In other cases, through-traffic may not be aware of the impact caused by excessive speeds and/or volumes. The following measures may be helpful in raising drivers' awareness of their driving habits:
  • Speed trailer - A self-contained, solar-powered device which displays vehicle travel speeds as determined by a radar gun. The device is housed in a trailer which is set up in a neighborhood for four to five days at a time and operates automatically.
  • Citizen Monitoring/publication of speeds - The Annapolis Police Department will loan a radar gun to community organizations after they receive a brief training class. The citizens may record the license number and speed of vehicles on the roadway, and this information can be published in a community newsletter. (The following vehicles were observed speeding on such date, etc.) This can be an effective way to raise the issue within a community, but it may also cause divisiveness within the community.
  • Fliers/newsletter articles - Communities may wish to publish articles in their newsletters asking residents to drive more responsibly or create special fliers on the issue. One community took a picture of all of the neighborhood children posing by the community sign and added the caption "28 Reasons Not To Speed in Our Community". This is less confrontational than speed monitoring, but it does not directly present drivers with evidence of their own behavior.
  • Demonstrations - Community groups can organize demonstrations along a roadway (such as a sidewalk parade or signs) to encourage drivers to slow down. Care must be taken to assure that the demonstration does not create a safety hazard for pedestrians or drivers, or become confrontational.
  • Physical Changes - Most drivers travel at a speed which feels comfortable. By changing the physical characteristics of the roadway, the speed at which they feel comfortable can be lowered. All such changes must be reviewed and approved by Road Operations, Solid Waste, the Board of Education, and Police and Fire Departments before implementation to assure that there is no unacceptable impact to the delivery of their services. In general, physical changes should be designed to accommodate any vehicle which was previously able to use the roadway (albeit at a reduced rate of speed). Diverters and one-way roadways are obvious exceptions to this goal, but even they can be designed to permit passage by certain vehicles.
  • Edgelines - On wide roadways (typically 36 feet or wider), the painting of edgelines can make the travel way appear narrower and thus reduce travel speeds. Generally, the two edgelines are painted 18 feet apart with no centerline. The area outside of the edgelines can be used as a parking lane, bike path, or shoulder area. Consideration should be given to prohibiting parking if there is not sufficient room to park between the curb and edgeline. It is not desirable to have parked cars straddling the edgeline.
  • Islands/Circles/Chokers - These are devices which slow drivers by forcing them to maneuver around an object in the roadway. Circles are raised areas within an intersection. Traffic traveling straight through the intersection must pass to the right of the circle. Left turning vehicles may turn left in front of the circle or travel 270 degrees to the right of the circle. (Specific circumstances at particular installations may require prohibiting one of those movements.) Islands are raised areas in the middle of a roadway between intersections. Vehicles in each direction pass to the right of the island. Chokers are raised areas on the outside edge of the roadway which are passed to the left (they mimic a parked car). These devices are typically tested using pre-cast concrete curb sections. This permits modifications (size or shape) to be made easily and allows the community to experience the change before committing to a permanent structure. If the device is successful and the community supports its use, a permanent structure can be installed.
  • Multi-way STOPS - The Manual on Uniform Traffic Control Devices (MUTCD), a national standard for the design and installation of traffic control devices, recommends that multi-way STOP signs not be used to control speeding. STOP signs are designed to designate right-of-way, and extensive experience across the country has demonstrated that they are ineffective in slowing traffic. Drivers on the main road soon learn that there is very little likelihood of encountering a vehicle coming from the side street and tend to roll through the intersection without stopping. As a general rule-of-thumb, we expect to see only 25% of the main street drivers come to a complete stop at an unwarranted STOP sign. Half of the drivers typically roll through the intersection at a reduced rate of speed, and the remaining 25% do not slow at all. Under certain specific conditions, multi-way STOPS may be an effective method of controlling an intersection. This generally occurs when there are relatively equal, moderate to heavy volumes on each street. In such cases, multi-way STOPS cause the right-of-way to be shared by both roadways and may prevent conflicts within the intersection. The MUTCD lists specific warrants for the use of multi-way STOPS.
  • Diverters - Diverters are channelizing devices which prevent certain movements from being made at an intersection. These can be effective in reducing through-traffic volumes.
  • One-way/Do Not Enter Traffic Patterns - ONE WAY and DO NOT ENTER signs can be used to control traffic flows and reduce through-traffic volumes. However, one-way travel patterns may lead to an increase in speeding as motorists do not face opposing traffic which might tend to hold down speeds.
  • Rumble Strips - Rumble strips are closely spaced raised bands of material on top of the pavement which cause vibration and noise when driven over. The resulting noise is usually not acceptable in a residential area, and the use of these devices is therefore limited to alerting drivers of particular hazards.
  • Speed Humps - A speed hump is an undulation in the pavement surface which causes vertical displacement as a vehicle passes. They are designed to be tolerable at or near the posted limit, but uncomfortable at higher speeds. They typically rise 3 inches in height over a distance of 6 feet and then fall the same height in another 6 foot distance with a ten foot flat section between the rise and fall. Parking lot style speed bumps (typically 6 to 8 inches high, 8 to 24 inches wide) can cause loss of control and will not be used on public roadways in the City of Annapolis.

    Speed humps cause an increase in emergency response time and are somewhat uncomfortable in many vehicles traveling at the posted speed limit. Accordingly, the City of Annapolis has endeavored to avoid an over-proliferation of speed humps by establishing the following conditions:

  1. Speed humps will be installed only after review by the Annapolis Fire Department, Annapolis Police Department, Board of Education and Public Works Services to assure that they will not impose an undue hardship on the operation of fire trucks, school buses, trash trucks, or snow plow equipment.
  2. Speed humps will not be considered on roadways which are classified as arterial or higher function roadways.
  3. Speed humps will not be placed on roadways that are less than 1000 feet long.
  4. Speed humps will generally not be considered on roadways where the average daily volume is more than 10,000 vehicles.
  5. Speed humps will only be considered on roadways where the posted speed limit is 25 or 30 mph. Speed limits will not be lowered solely for the purpose of meeting this criterion.
  6. The following volume, speed, and community funding warrants must be met.

If Average Daily Volume is

at least ...

..and Average Travel Speed (50th percentile) is

at least ...

..speed humps will be allowed if the
Community funds ...
750 vehicles 10 mph above the posted limit 100% of construction
1000 vehicles 5 mph above the posted limit 100% of construction
1000 vehicles 10 mph above the posted limit 50% of construction
1500 vehicles 5 mph above the posted limit 50% of construction
  • On roadways where there is some extraordinary circumstance, the City may decide to fund 100% of the costs of speed humps. These will be evaluated on a case-by-case basis.
  • Except in extraordinary circumstances, no more than six speed humps will be placed along the primary response route between any dwelling unit and the first-responding fire station.
  • The City retains the right to modify or waive these conditions as the City considers necessary or advisable.
  • Raised Crosswalks/Intersections - These devices are similar to speed humps in terms of vertical displacement and are used to slow vehicles at crosswalks or intersections. The criteria noted above for the installation of speed humps also apply to raised crosswalks and intersections.
  • Roundabouts - A roundabout is (typically) a small traffic circle such as is found in Europe and Australia. All entering vehicles must yield to traffic in the circle (as opposed to Washington, D.C. or New Jersey circles where traffic in the circle is often required to yield to entering traffic). All traffic must move around the roundabout in a counterclockwise direction (as opposed to the speed control circles described above). The principal benefit in using a roundabout is that it allows for more efficient use of the intersection than either STOP signs or traffic signals (in most cases) since very few vehicles are required to come to a complete stop. By limiting the number of conflict points presented to each entering driver, a roundabout will also increase the safety of most intersections. A side benefit of a roundabout is that it will slow through-traffic. However, roundabouts usually can not be fit into an existing intersection without encroaching on the corner lots, so they are often not appropriate for speed control in existing neighborhoods.
  • Enforcement: Police enforcement of speed limits can be effective if it occurs consistently over a long period of time. This may not be an efficient use of Police personnel on relatively low-volume, residential streets, and often leads to community resentment ("How come you're giving the tickets to the residents and not those outside speeders?"). Accordingly, it is often not effective in controlling speeding in residential areas. The attached table lists the criteria which should be considered when selecting what type of action(s) should be considered to control traffic in a residential area.

COMMUNITY INPUT: The City retains the responsibility for its roads and rights-of-way, and has the sole authority to decide whether or not any physical or regulatory changes will be implemented. In the absence of an identified safety problem, however, neighborhood traffic control techniques will not be implemented unless there is substantial agreement and support within the affected communities. Speed humps and other physical changes such as islands, circles, and chokers will only be installed after completion of a Neighborhood Traffic Study and in accordance with City standards regarding type, design, location, and spacing of devices. Specifically, residents must be made aware of the signing and markings associated with speed humps and the possibility that emergency response vehicles will be delayed by 3 to 9 seconds per hump. Depending upon the actual design, similar delays may be expected for circles, islands, and chokers.

The City will not rely on pre-set community approval ratings, but rather will strive to help the impacted community reach general agreement on the nature of the problem and the proposed solution. The assumption underlying this approach is that neighborhoods will support the use of traffic calming techniques (even though they involve some negative impacts) if the citizenry agree that: there is a problem; the proposed solution is the most appropriate; and their concerns have been addressed and mitigated as well as possible. This support will generally be in the form of a recommendation by the community association and the agreement of most of the affected property owners. The definition of "most of the affected property owners" will, of necessity, need to be considered on a case-by-case basis. At the very least, it will include properties near the proposed devices, properties along the road on which the devices are proposed, and properties whose only route of access includes the road on which the devices are proposed, with primary consideration being given to those living in the area directly impacted by the problem and proposed solution. Nearby residents who do not necessarily need to use the route in question should also be notified, particularly where the placement of speed humps in one community may affect the number of humps allowed in another community. Where the implementation of a plan may tend to divert traffic to other residential areas, those areas will also be included in the plan review and approval process.

The City will require proof of community involvement and discussion of any proposed changes. The community must demonstrate that all impacted residents have been made aware of the problem(s) and proposed solution(s) and have been given an opportunity to ask questions, receive answers to those questions, and offer comments. Such proof can be in the form of copies of newsletters/fliers, community meeting minutes, or petitions/ballots.

OTHER AGENCY INPUT: Physical devices such as speed humps, circles, islands, and chokers will generally be placed at spacings of not less than 400 to 600 feet. They will be installed only after review by the Annapolis Fire Department, Annapolis Police Department, Board of Education and Public Works Services to assure that they will not impose an undue hardship on the operation of fire trucks, school buses, trash trucks, or snow plow equipment.

Guidelines for Selection of Neighborhood Traffic Control Techniques
Speed Trailer Only one through-lane in each direction.   See Note 1. 500 - 5000 Yes 0 - 3 mph No Both
Publication of speeds Minor collector or below. Residential street with little through-traffic. See Note 1. 500 - 5000 Yes ? No Both
Fliers/Articles Any 500 - 10,000 Yes ? Sometimes Both
Demonstrations Major collector or below with sufficient room to accommodate demonstrators away from roadway surface. 500 - 5000 Yes ? Sometimes Both (closed preferred)
Edgelines Major collector or below with minimum 32' width (or consider parking restrictions). 500 - 10,000 Yes 0 - 3 mph No Both
Islands/Circles/Chokers Major collector or below. Posted Limit <30 mph. minimum 26' width for islands and chokers, minimum 42' diagonal at intersection for circles. See Note 2. 500 - 10,000 Yes 3 - 7 mph No Closed
Multi-way STOP See MUTCD See MUTCD No 0 No Both
Diverter Must be an appropriate alternate route. N.A. No N.A. Yes Closed
One-Way/Do Not Enter Must be an appropriate alternate route. N.A. No N.A. Yes Both
Rumble Strips Any 500 - 5000 Sometimes ? No Both
Speed Humps Major collector or below Posted Limit <30 mph. 50 percentile minimum 5 mph over posted limit. See Note 3. 1000 - 10,000 Yes 3 - 7 mph Sometimes Both
Raised Crosswalks/ Intersections Major collector or below. Posted Limit <30 mph. 50 percentile minimum 5 mph over posted limit. May require additional storm drain inlet(s). 1000 - 10,000 Yes 3 - 7 mph Sometimes Both
Roundabouts Any 1000 - 25,000 Sometimes 0 - 5 mph No Both
Enforcement Major collector or above Minimum 2000 Yes 0 - 5 mph No Both


  1. Requires adequate room for observers and equipment.
  2. Requires curbing near device to prevent vehicles from driving around it. Curbing must be placed on open section road to use these.
  3. May require curbing near device to prevent vehicles from driving around it.

    ?     No documentation.

ADT = Average Daily Traffic     MUTCD = Manual on Uniform Traffic Control Devices     N.A. = Not Applicable