Traffic Calming Program (Formerly Speed Hump Petition)

Introduction

The City of Titusville Public Works Department regularly gets citizen requests for review of local traffic conditions with regard to volume and speed. Traffic calming is a method used to address both concerns while still maintaining access to City services. 

What is Traffic Calming?

The primary purpose of traffic calming is to support the livability and vitality of residential and commercial areas through improvements in non-motorist safety, mobility, and comfort. These objectives are typically achieved by reducing vehicle speeds or volumes on a single street or a street network. Traffic calming measures consist of horizontal, vertical, lane narrowing, roadside, and other features that use self-enforcing physical or psycho-perception means to produce desired effects.

A variety of definitions are commonly used in the traffic calming field and although the exact wording may differ, the essence remains; traffic calming reduces automobile speeds or volumes, mainly through the use of physical measures, to improve the quality of life in both residential and commercial areas and increase the safety and comfort of walking and bicycling.

What is the Purpose of Traffic Calming?

Traffic calming has helped to increase the quality of life in urban, suburban, and rural areas by reducing automobile speeds and traffic volumes on neighborhood streets. The implementation of traffic calming on residential streets is illustrative of the tools that traffic engineers and planners can use to meet broader societal needs to facilitate all street users’ safe and efficient movement. Traffic calming measures can help to transform streets and aid in creating a sense of place for communities.

The practice of traffic calming has evolved in recent years from a neighborhood-specific treatment to an integral part of complete streets and other bicyclist/pedestrian-related projects. Although mostly known as a neighborhood-specific initiative, traffic calming can be implemented on different street types and in different areas, including commercial settings and rural areas. Neighborhood traffic calming as a stand-alone approach to address traffic concerns isn't as prevalent as in past decades, with fewer new or updated neighborhood traffic calming programs due to funding constraints. However, the desire of citizens to slow automobile speeds or reduce volumes on streets adjacent to their homes has not decreased, and neighborhood traffic calming programs often provide the most effective way for residents to request traffic calming on residential streets.

Traffic calming within neighborhoods is unique as local residents are often the primary group interested in addressing automobile speeds and traffic volumes. Therefore, it is important that there continue to be a clear process for the planning, evaluation, and implementation of neighborhood traffic calming. As a comparison, the other major uses of traffic calming in cities are driven by multiple facets, whether by the bicyclist advocacy community in the case of bicycle boulevards or by safety advocates in the case of complete streets projects and emerging Vision Zero policies, for example. Neighborhood traffic calming continues to provide residents with a means to address traffic concerns in their neighborhoods.

The importance of reducing vehicle speeds cannot be overstated in an area where there is potential for conflict between a pedestrian and a motor vehicle. The slower the speed of the motor vehicle, the greater the chances are for survival for the pedestrian. If struck by a motor vehicle traveling at a speed of 20 miles per hour or less, a pedestrian is typically not permanently injured. Pedestrians are usually fatally injured if struck by a motor vehicle traveling at a speed of 36 miles per hour or more.

City of Titusville Traffic Calming Process Map

STEP 1 - Identification of Traffic Concern and Eligibility Review

Identification and eligibility determination of neighborhood traffic concerns consist of the following five-step process: 

1. Resident completes Request Form and submits to Public Works Department; 
2. Public Works Department collects basic speed and volume data; 
3. Public Works Department determines if the concern is eligible for traffic calming process; 
4. If eligible, Public Works Department determines “Affected Areas” and “Impacted Areas”; 
5. Residents obtain signatures from at least 50% plus 1 of the property owners within "Impacted Area” and submit them to Public Works Department.

A. Resident Completes Request Form and Submits to Public Works Department

The process starts when a resident or community group submits a Request Form, which can be found on the City website, to the Public Works Department. A copy of the Request Form and accompanying Traffic Study petition form is included in the Appendix. City staff will determine if the street or intersection of concern is applicable for consideration by the Traffic Calming Program. To be eligible for the program, the street must: 

• Be a residential neighborhood under the City of Titusville’s jurisdiction; 
• Have traffic volumes greater than 300 vehicles per day; 
• Have a posted speed limit of 30 mph or less; 
• Be at least 500 feet in length; 
• Not be cul-de-saced.

B. Public Works Department collects basic speed and volume data

Once the Request Form has been reviewed by staff, the next step in the Traffic Calming Program involves collecting related traffic data to confirm the existence and magnitude of the traffic concern. Public Works Department will obtain site data including traffic volumes and speeds.

C. Public Works Department determines eligibility for traffic calming process

After the Public Works Department determines project eligibility, if there are numerous eligible projects in the queue, then the Public Works Department will prioritize the project areas. Prioritizing factors include:

• First come, first served; 
• The need for traffic calming in the requested area. Based on the data collected, priority in the program may be determined by definable criteria related to: 
  • Traffic Speeds: 
    As motor vehicle speed increases, noise increases, and pedestrian and bicycle safety decreases. Some of the most dangerous traffic safety situations involve infrequent vehicles traveling substantially above the speed limit.
  • Daily Traffic Volume Levels:
    As motor vehicle volume increases, noise increases, and pedestrian and bicycle access decreases. This also causes the local function and feel of a street to diminish. From studies measuring resident opinions, the ideal traffic volume on a local neighborhood street is less than 300 vehicles per day (vpd), and residents generally are able to accept volumes up to 800 vpd. 

Table 1: Traffic Calming Thresholds 

The table below summarizes the traffic concern characteristic thresholds required for a neighborhood street to be considered for traffic calming considerations. One or more of the three thresholds should be met to proceed with traffic calming measures. 

If the results of the study conclude that the criteria for traffic calming have not been met, staff will conclude that the concern is not eligible for the traffic calming program at this time. The concern cannot be brought back to the City for three years unless something significantly changes existing conditions. 

If the review of the data verifies that one or more of the thresholds have been met, they will determine the “Affected Areas” and “Impacted Areas” as described below.

D. Public Works Department Determines “Affected Areas” and “Impacted Areas”

After the City receives a traffic concern and determines it is eligible for the Traffic Calming Program, staff will define an “Affected Area” and an “Impacted Area.” An “Affected Area” includes all property directly affected by the traffic issue. An “Impacted Area” includes any property that would be impacted by any proposed traffic management solution.

The size and extent of the impacted area will take into consideration the type of traffic calming being proposed, the type of properties in the vicinity, and the characteristics of the street network surrounding the proposed project site(s).

These areas may include:

• All properties abutting the proposed street segment to be modified. 
• All properties on adjacent street(s) with ingress/egress only possible via the modified street segment. 
• All properties on adjacent street(s) that have alternative points of ingress/egress but will be otherwise affected by the modified street segment.

Spot-specific concerns will generally relate to a particular intersection or street segment, whereas neighborhood-wide concerns will generally relate to conditions or behaviors affecting the neighborhood street network. The City may elect to treat some spot-specific concerns as neighborhood-wide concerns if it decides that they could be better addressed in the context of the street network system. At the City’s discretion, the potentially affected area for a spot-specific concern may be extended to the entire street block. The potentially affected area for a neighborhood-wide concern should generally be a distinct area that is bounded or bisected by major roadways or geographic features. If the traffic concern influence area (but not the specific street being considered) may impact a larger neighborhood area the City will inform residents of the larger neighborhood area of the perceived problem and potential traffic calming alternatives under consideration.

E. Residents obtain signatures from at least 50% plus 1 of property owners within "Impacted Area” and submit to Engineering.

The City will provide a map or description of the impacted area indicating individual properties in the area to the requester. Requesters must obtain signatures from at least 50% plus 1 of the property owners within the impacted area to move forward with the request for a neighborhood traffic management effort (the petition can be found in Appendix).

Step 2 - Initial Traffic Calming Phase One Solutions

Generally, it is desirable to address traffic problems with the least restrictive measures possible and move to more costly geometric solutions only after other measures have proven ineffective. Therefore, City staff may choose to implement fairly low-cost, undisruptive initial traffic management solutions before proceeding into more formative calming measures. These solutions fall into three categories: Encouragement, Enforcement, and Engineering. The categories are explained below.

A. Encouragement

The neighborhood can be educated concerning the traffic management problem. This education can include the use of a Radar speed trailer.

B. Enforcement

If police resources are available, regular and random patrol and enforcement activities can address speeding and other traffic control concerns.

C. Engineering

The City may choose to install enhanced signing or pavement markings to address concerns. Initial cost and any ongoing maintenance costs of these Phase One measures may need to be paid for by the residents. Examples of these measures can include: 

• Roadway narrowing through pavement marking of medians or bike lanes 
• Increased visibility of pedestrian crossing pavement markings 
• Additional pedestrian crossing signs 
• Appropriate speed limit signs

Step 3 - Phase Two Solutions

After a predetermined time period, the Public Works Department will evaluate the effectiveness of the non-construction elements of the Phase One plan. The results of this study will be presented to the petitioner. If the Phase One efforts are not satisfactory, Phase Two traffic calming techniques will be considered.

The Public Works Department will consider Phase Two engineering solutions such as bump outs, chokers, traffic circles, chicanes, speed tables, diverters, closings, etc. The City will analyze the options and make a recommendation for the appropriate engineering countermeasures. The Public Works Department will take into consideration such items as street sweeping, and the impact to ambulances, fire, and police when determining these solutions. Solutions in the Traffic Calming Toolkit are discussed in the Appendix.

Residents in the affected area must achieve a 50% + 1 positive vote of the property owners in the affected area. There is one vote per property. The Public Works Department will finalize construction plans and project specifications upon approval of the necessary funds to complete the project. 

Step 4 – Priority Ranking Process

A. Scoring 

Because of limited resources, the City may not be able to implement all traffic calming projects proposed by the Traffic Calming Program. The Traffic Calming Program scoring system allows the City to prioritize traffic calming projects based on the following neighborhood street and land use characteristics. These characteristics include the initial set of traffic calming guideline thresholds plus additional land use and City planning-related considerations such as:

• Traffic speeds 
• Daily traffic volumes levels 
• Motor vehicle crashes 
• Proximity to schools and parks 
• Critical locations
• Pending road construction 
• Relationship to neighborhood and City plans 

B. 85th Percentile Motor Vehicle Speed 

The point value for this criterion is equal to the 85th percentile motor vehicle speed (in miles per hour) measured on the subject street, minus 25. 

C. Significant Motor Vehicle Speed 

The point value for this criterion is the percentage of traffic that is traveling at least 10 mph above the speed limit. 

D. Average Daily Traffic Vehicle Volume 

The point value for this criterion is equal to the average daily traffic vehicle volume (in vpd) divided by 1,000 and rounded to the nearest whole number. If possible, the motor vehicle volume should be measured over a 48-hour period. 

E. Crash History 

The point value for this criterion is the number of crashes that have occurred at this location over the last three years excluding non-correctable crashes such as those involving driver health-related seizures, or motorists operating a vehicle under the influence

F. Distance from Park or School

Motor vehicle noise can have an adverse impact on parks and schools. In addition, these facilities typically attract pedestrians and bicyclists, especially children. Bicycle and pedestrian volumes (or demand) are typically the highest on streets adjacent to these facilities and decrease as the distance from the facility increases.

The point value for this criterion is equal to one one-hundredth of the difference of 1,000 and the linear street or sidewalk walking distance between the subject street and the nearest park or school. The minimum point value is 0. Other pedestrian-oriented facilities (such as the library or pool) may also be considered for this criterion. For example, if the problem area on the subject street is 400 feet away from a park, the point value associated with this distance will be (1,000- 400) x 0.01 = 6.

G. Critical Location

Certain intersections or street segments have the potential for acute conflict between motorized and non-motorized traffic. These “critical locations” may include: 

• Multiuse trail crossings 
• Intersections where the minor street is marked as a bicycle route 
• Intersections staffed by a school crossing guard 
• Streets or intersections with high bicycle or pedestrian volumes 
• Streets or intersections with high (unmet) bicycle or pedestrian demand 
• Streets or intersections within a school zone 

A project that improves conditions for bicyclists or pedestrians at a critical location may receive up to 10 points for this criterion, depending on the extent of both the need and the improvement.

H. Pending Road Construction

Traffic calming measures can be easily implemented at little additional cost when roadway plans are prepared for reconstruction. When residential streets are planned for reconstruction, the City may seek to capitalize on this opportunity and encourage the implementation of traffic calming measures as part of the reconstruction project. To acknowledge this criteria and opportunity, up to 10 points are awarded to the scoring.

I. Neighborhood and City Planning

Neighborhood-wide projects typically require extra effort and produce more comprehensive traffic management solutions. To acknowledge this effort, the City may award 5 points to a neighborhood-wide project for this criterion. This is a subjective measure.

The score for a neighborhood-wide project is the average of scores for individual project elements rounded up to the next whole number. The addition of 5 points reduces the penalty incurred by individual project elements that score lower than the overall project average but as a Scoring Priority Calculation system provide a positive synergistic enhancement to calming the neighborhood street network problem.

J. Formal Review

The table below summarizes the scoring criteria, which are explained in the following subsections. The proposed project’s score is the sum of the point values for each of the criteria. Projects with a score of 15.0 or more are eligible for physical traffic calming measures.

Table 2: Project Prioritization Scoring Criteria

This score is used to prioritize the projects under implementation consideration. The project is placed on the Traffic Calming Project list, and its score is compared to other projects that have been proposed but not yet implemented. If the project receives a high score that places it near the top of proposed projects, the process continues. 

Unimplemented projects remain on the Traffic Calming Project list for three years. Every three years, the advocate is notified and may submit a new application to keep the project on the list for an additional three years.

The Public Works Department will review the project and makes a recommendation to the City Council. This review includes the project score, the project action plan, the proposed measures, the results of any temporary installations (if applicable), and the results of the balloting.

The City Council will make the final determination on whether or not to implement the project.

Priority Scoring Example:

Projects with a score of 15.0 or more are eligible for physical traffic calming measures.

Acceptable Traffic Calming Measures

All traffic calming measures shall comply with the Manual of Uniform Minimum Standards for Design, Construction and Maintenance for Streets and Highways latest edition. The following measures are acceptable for Local Streets:

Lateral Shift

A lateral shift is a realignment of an otherwise straight street that causes travel lanes to shift in one direction. The primary purpose of a lateral shift is to reduce motor vehicle speed along the street. A typical lateral shift separates opposing traffic through the shift with the aid of a median island. Without the island, a motorist could cross the centerline in order to drive the straightest path possible, thereby reducing the speed reduction effectiveness of the lateral shift. In addition, a median island reduces the likelihood a motorist will veer into the path of opposing traffic, further improving the safety of the roadway for motorists. 

Chicane

A chicane is a series of alternating curves or lane shifts that are located in a position to force a motorist to steer back and forth out of a straight travel path. The curvilinear path is intended to reduce the speed at which a motorist is comfortable traveling through the feature. The lower speed could in turn result in a traffic volume reduction.

Realigned Intersection

For the purpose of traffic calming, a realigned intersection is the reconfiguration of an intersection with perpendicular angles to have skewed approaches or travel paths through the intersection. The expectation is that these physical features will remove or discourage fast vehicle movements through the intersection.

The most common application is the conversion of a T-intersection with straight approaches into curving streets meeting at right angles. The result is the removal of all straight paths through the intersection.

Traffic Circle

A traffic circle is a raised island, placed within an unsignalized intersection, around which traffic circulates. A traffic circle forces motorists to use a reduced speed when entering and passing through an intersection, whether the vehicle path is straight-through or involves a turn onto an intersecting street.

A traffic circle can have Stop signs or Yield signs on the intersection approaches.

The primary benefit of a traffic circle is an expected reduction in the number of angle and turning collisions. An additional benefit is that it can slow high-speed traffic at the intersection.

A typical traffic circle has a horizontal clearance that is too small for a left-turning truck, emergency vehicle, or bus to circulate counterclockwise even with a partially mountable center island. If the local jurisdiction permits the movement, the large vehicle can make a left turn in front of the island. However, some jurisdictions prohibit turning in front of the island. A traffic circle is usually circular in shape but may be oval to fit a particular intersection.

Small Modern & Mini-Roundabout

A small modern roundabout and mini-roundabout is a raised island, placed within an unsignalized intersection, around which traffic circulates. The center island forces a motorist to use reduced speed when entering and passing through an intersection, whether the vehicle path is straight-through or involves a turn onto an intersecting street. It is also expected to reduce the number of angle and turning collisions.

Both a small modern roundabout and a mini-roundabout are designed in accordance with roundabout design principles. Both are designed so that all traffic can circulate counterclockwise around or partially over the center island.

The principal difference between a small modern roundabout and a mini-roundabout is found at the center island. For a small modern roundabout, the center island is not traversable and can be landscaped with ground cover, flowers, and street trees. In contrast, the center island of a mini-roundabout is fully traversable.

Speed Hump

A speed hump is an elongated mound in the roadway pavement surface extending across the travel way at a right angle to the traffic flow. A speed hump is typically 3 inches in height (with applications as high as 4 inches) and 12 feet in length along the vehicle travel path axis (note: a speed hump that is 20 feet in length and flat in the middle is considered a speed table in this).

At typical travel speeds along a residential street or in a small commercial business district, a speed hump produces sufficient discomfort to a motorist driving above the speed hump design speed to discourage speeding. It encourages the motorist to travel at a slow speed both upstream and downstream as well as over the speed hump.

Speed Cushion

A speed cushion consists of two or more raised areas placed laterally across a roadway. The height and length of the raised areas are comparable to the dimensions of a speed hump. The primary difference is that a speed cushion has gaps (often referred to as "cutouts") between the raised areas to enable a vehicle with a wide track (e.g., a large emergency vehicle, some trucks, some buses) to pass though the feature without any vertical deflection.

Another difference between a speed cushion and a speed hump is the common practice for the top of the speed cushion to be level. Like a speed hump, the profile of a speed cushion is gentle enough to provide a comfortable ride when traversed at a speed of approximately 20 to 25 MPH.

Speed Table

A speed table is a raised area placed across the roadway designed to physically limit the speed at which a vehicle can traverse it. Like a speed hump, it extends across the travel way. Unlike a speed hump, a speed table has a long enough flat top (typically, 10 feet) to accommodate the entire wheelbase of most passenger cars. The longer longitudinal depth in the direction of travel enables comfortable and safe vehicle operating speeds that are faster than for a speed hump. 

When a speed table is designated as a crosswalk through the use of striping, it is known as a raised crosswalk.

Offset Speed Table

An offset speed table is a raised area placed across the roadway designed to physically limit the speed at which a vehicle can traverse it. Like a speed table, it extends across the travel way and has a long enough flat top (typically, 10 feet) to accommodate the entire wheelbase of most passenger cars.

The offset speed table is split down the centerline of the street with the two halves separated longitudinally. The offset tables enable an emergency response vehicle to bypass the speed tables by traveling in the opposing traffic lane for a short distance. This maneuver removes most of the emergency vehicle delay associated with a standard speed table.

Raised Crosswalk

A raised crosswalk is a variation of a flat-topped speed table. A raised crosswalk is marked and signed as a pedestrian crossing. The 10-foot flat top on a typical speed table conforms to a desired crosswalk width.

There are two distinct raised crosswalk designs. Both use a modified version of the common 22-foot speed table:

• The most common type is constructed flush against the roadside curb.
• The other type is constructed on an open section (requiring a curb ramp on the raised crosswalk) or separate from the curb (requiring a curb ramp on both the curb and the raised crosswalk).

A raised crosswalk improves pedestrian safety by causing motorist speed to decrease at the crossing.

A raised crosswalk is typically between 3 and 6 inches above street level. It is common for a raised crosswalk to be level with the street curb. This height increases the visibility of a pedestrian in a crosswalk to a motorist. It also improves the line of sight for a pedestrian toward an oncoming vehicle.

A raised crosswalk can be placed mid-block or at an intersection

Raised Intersection

A raised intersection is a flat, raised area covering an entire intersection with ramps on all approaches. It is essentially a speed table that covers an entire intersection, including the crosswalks.

The purpose of a raised intersection is to slow vehicle traffic through the intersection and to improve safety for pedestrians. It has the advantage of calming two streets at once.

A raised intersection typically rises to sidewalk level.

A raised intersection is especially applicable in a dense urban area. A typical installation is at a signal-controlled or all-way stop-controlled intersection with a large volume of street-crossing pedestrians. A raised intersection reinforces the need for a motorist to drive cautiously and be wary of crossing pedestrians.

Corner Extension

A curb extension is a horizontal extension of the sidewalk into the street resulting in a narrower roadway section. This device may be used at either corner or midblock. A curb extension at an intersection is called a corner extension or bulbout. A curb extension located midblock is called a choker.

When combined with on-street parking, a corner extension can create a protected parking bay.

The effect of a corner extension on vehicle speeds is limited because of the absence of either a pronounced vertical or horizontal deflection. Its primary purpose is to "pedestrianize" an intersection. A corner extension (with a reduced corner radius) slows automobile turning speeds, shortens pedestrian crossing distance, and increases pedestrian visibility.

When a corner extension is part of a downtown redevelopment project, it can go hand-in-hand with on-street parking bays and crosswalks (in "safe cross" designs).

A corner extension can be combined with a vertical speed control device (e.g., a raised crosswalk) to achieve a greater reduction in vehicle speed.

Choker

A choker is the narrowing of a roadway through the use of curb extensions or roadside islands. It can be created by a pair of curb extensions at a midblock location that narrows the street by widening the sidewalk or planting strip at that location. A choker can also be created through the use of roadside islands. This narrowing is intended to discourage motorist speeding and to reduce vehicle speeds in general.

Within a choker on a two-way, two-lane roadway, vehicles are able to pass each other without conflict. But the narrower cross-section lowers the margin of error for motorists who, as a result, tend to moderate their speed. In some applications, a double-lane choker is combined with a median island as a means to reduce the possibility of opposing vehicle conflicts.

A one-lane choker forces two-way traffic to take turns going through the pinch point. If the roadway is narrowed to a single lane, the lane can be either parallel to the initial roadway alignment or angled to the alignment. The former is called a parallel choker, the latter an angled choker, twisted choker, or angle point.

A choker can be located at any spacing desired for traffic calming. A choker is often combined with on-street parking to create a protected parking bay.

Landscaping on a choker can make the traffic calming feature attractive and can make it more visible to the motorist.

A choker may be a good location to place a midblock crosswalk (either level with the roadway or as a raised crosswalk) because it shortens the distance a pedestrian walks on the travel way.

Median Island

A median island narrowing is a raised island located along the street centerline that narrows the travel lanes at that location. The visual appearance of narrowed lanes encourages a motorist to slow.

A median island is physically different from and serves a different purpose as a standard median on a 4-or-more-lane roadway. The latter median provides separation between opposing vehicle travel lanes, an opportunity for landscaping or visual enhancements to a roadway corridor, and a place of refuge for a pedestrian crossing a multi-lane street – all in support of improved and safe traffic flow.

A median island may simply be a painted area that is designated for non-automobile use. But a median island is most effective when it is defined by a raised curb and landscaped to further reduce the open feel of a street. Median islands often incorporate textured pavement on the island itself, particularly for a median island without a raised concrete curb.

A median island can often double as a pedestrian refuge island if a cut in the island is provided along a marked crosswalk. Where there is an existing midblock crosswalk, it is desirable to locate the median island at the crosswalk.

When placed at or near the entrance to a neighborhood, a median island provides a visual cue to the motorist about the preferred vehicle speed. If a median island has textured pavement on either side or a monument sign, it can serve as a gateway or entry feature.

On-Street Parking

On-street parking can effectively narrow the roadway travel lanes by adding side friction to the traffic flow. On-street parking can be allowed on one or both sides of a roadway. Or parking zones can be strategically located on alternate sides of a roadway to create a chicane effect.

Whether on-street parking can be an appropriate traffic calming measure is a direct function of its actual or potential usage (i.e., parking demand). In order for the presence of on-street parking to be an effective and safe traffic calming measure, it must be occupied with parked vehicles during the time when traffic calming is desired.

The different types of on-street parking (parallel and both front-in and back-in angled) have different horizontal width effects and operational effects.

Both parallel and angle vehicle parking can be protected through the use of protected parking bays or the use of complimentary traffic calming measures such as a corner extension, midblock choker, or chicane.

Half Closure

A half closure is a physical barrier that blocks vehicle travel in one direction (i.e., creates a one-way street) for a short distance on an otherwise two-way street. A half closure is defined to be placed at an intersection with the intent to obstruct selected traffic movements to or from the intersection.

A half closure can block either traffic entering the side street (i.e., the traffic-calmed street) or exiting the side street, depending on its placement. The traffic movement that is obstructed by the half closure is rerouted along an alternative path.

A half closure is designed to deter illegal maneuvers around the measure. Its length is typically longer than a passenger car so a wrong-way motorist needs to travel an uncomfortable distance. A typical application has the half closure extend to the street centerline, leaving a relatively tight opening for a wrong-way motorist.

In a typical application, bicyclist and pedestrian traffic can be accommodated through the closure on a path built behind the vehicle barrier.

Median Barrier and Forced Turn Island

Median barrier and forced turn island are two variations of physical turn restrictions at an intersection that can be used to eliminate specific traffic flows (in particular, cut-through traffic) from entering or exiting a side street.

A median barrier is a raised island placed through an intersection, along the centerline of a roadway (often the higher-order roadway), preventing a motorist from traveling straight through the intersection on the side street. A median barrier can be designed to allow turns to and from the main street while preventing through-traffic from the side street from crossing the main roadway.

A forced turn island is a raised island that blocks certain movements on approaches to an intersection. It can force a motorist to turn right from the side street (by blocking left-turn and through movements).

A forced turn island is a raised traffic island, typically triangular in shape, placed at the mouth of an intersection. It channels traffic to the right and blocks left and through movements. It can constrain traffic entering the intersection on the approach leg with the island, exiting the intersection on the approach leg, or both. Its turning traffic restrictions are similar to those of a median barrier.

Depending on its design, a median barrier can also reduce vehicle speed on the main street through lane narrowing (it then, in traffic calming terms, is also a median island). These physical restrictions are more effective than those that rely solely on signage and markings. They also do not require enforcement.

A single median barrier or single forced turn island may simply shift traffic (and its associated problems and issues) onto other local streets. In order to prevent a traffic shift from one local street to another, a series of median barriers or a comprehensive set of forced turn islands can be installed at all minor street intersections along a section of the major street.

Traffic Calming Program Forms

To initiate the traffic calming process, please fill out the Traffic Calming Program Request Online Form or print and return the Traffic Calming Program Request Paper Form to the Public Works Department.

Traffic Calming Program Petition