Section 1 C. Traffic Engineering 2. Traffic Calming

SECTION 1 STANDARD DESIGN AND PLAN PRODUCTION CRITERIA

SECTION 1 STANDARD DESIGN AND PLAN PRODUCTION CRITERIA

C. Traffic Engineering

2. Traffic Calming

The work of this section consists of providing the methodology to study a problematic street and/or area within the City of Miami Beach boundaries.  The installation of traffic calming devices is regulated by the Miami Beach Traffic Calming Manual. This manual provides the methodology which includes policies, techniques and process and procedures to install traffic calming devices.

The Traffic Calming Manual provides the process and procedures to study a problematic street and/or area within the City of Miami Beach boundaries.

A. Policies:

Specific points to consider in the design of traffic calming schemes include:

• Streets that are classified as arterial, collector or higher shall not be considered under this traffic calming guidelines.

• Emergency vehicles access must be preserved. Fire and Police Departments should be involved from the beginning.

• The cut-through traffic should be routed back to collector and arterial roadways.

• Public Works Department should look at the redistribution of traffic in adjacent streets. The impacts on adjacent streets and arterials must be measured.

• Public Works Department should look at the origin of the problem. No one uses a short-cut unless there is a reason to.

• Buses need to be able to negotiate traffic calming features safely, without undue discomfort to passengers and at a reasonable operating speed.

• Signing to ensure that Heavy Goods Vehicles (HGVs) and other ‘through’ traffic choose suitable routes that reduce the environmental impact of their journeys.

• Bicyclist and pedestrian access must be accommodated. Provision for pedestrians and cyclists should be of a high quality to promote the shift from the private car to more sustainable modes of transport. Adequate widths and carefully considered routes and priorities coupled with arrangements to make access for disabled people as easy as possible are required.

Public Works Department may recommend employing different traffic calming devices according to neighborhood’s characteristics. Final decision will depend on consensus with the community.

B. Techniques:

PHYSICAL: In general, wider roads encourage higher automobile speeds. Many traffic-calming techniques are therefore designed to physically change the width of the street. If motorists can see far into the distance, their speed may increase. The interruptions of sight lines through changes in the road’s direction, or breaking the road into smaller visual units using techniques such as chicanes and roundabouts, cause the drivers to slow down.

PSYCHOLOGICAL: Traffic calming may also be achieved by changing the psychological feel of the street. Streets using different surface types, vertical landscaping or narrowed lanes create the appropriate space for a relaxed, pedestrian-friendly atmosphere. These psychological changes give motorist cues that they are no longer on a major roadway, but are in a different environment that is shared with people.

There is an extensive menu of treatments that may be part of a traffic calming strategy. Such treatments include:

DEFLECTING PATHS: Deflecting the vehicle path causes the driver to reduce speed and be more attentive to the task of driving. Deflection is done through changing the route of the automobile. Some measures apply at mid-block locations, while others are most appropriate for intersections.

DIVERTING TRAVEL ROUTES: Diverting the driver’s route increases travel time and encourages the driver to use another route. Traffic diverters, street closures, one-way streets, median closures and turning movement restrictions are examples of a diversion.

CHANGES TO PAVEMENT SURFACE: Changing the pavement surface demands attention from drivers, and reduces the speed for comfortable driving (the .design. speed). Speed humps, brick pavers and special pavement materials are among the most frequent approaches to changing the pavement surface.

TRAFFIC CONTROL DEVICES: Traffic control devices, where warranted, can be used to regulate traffic patterns.

ENFORCEMENT: Intensified enforcement of traffic regulations can calm traffic, generally, by reminding drivers of posted speed limits and by enforcing the observance of STOP signs. Police officers are the usual source of intensified enforcement, but neighborhood volunteers can also be very effective in assisting in an enforcement effort.

EDUCATION: The City of Miami Beach will make a conscious effort to initiate and maintain an educational program on traffic calming and safety within the city:

C. Process and Procedures:

Diagram

1. COMPLETE AND SUBMIT PROJECT APPLICATION: A preliminary traffic calming study can be initiated by a resident complaint, the request of a neighborhood association, or a Commissioner’s request. The application in Appendix A of this document should be completed and submitted to the Public Works Department.

2. EVALUATE APPLICATION:  City staff will identify the study area, collect preliminary data (the Miami Beach Public Works Department will perform speed and volume studies, collect accident reports), and complete the evaluation of the traffic calming request.

Speed and traffic volumes are the first criteria used to gauge whether a traffic calming study area warrants further research for possible development and implementation of a traffic calming plan. The tables below shown the thresholds established for Miami Beach regarding speed and volume:

Speeding Table

Points

85th speed is… above speed limit

 

Points

volume 24 hr.

0.5

less than 4.6 mph

 

0.5

500 – 750 veh.

1.0

4.6 to 7.5 mph

 

1.0

751 – 1,100 veh.

1.5

7.6 to 10.5 mph

 

1.5

1,101 – 1,700 veh.

2.0

10.6 to 13.5 mph

 

2.0

1,701 – 2300 veh.

2.5

13.6 to 16.5 mph

 

2.5

More than 2,300 veh

3.0

more than 16.5 mph

 

 

 

* The 85th percentile speed is defined as “the speed that is exceeded by 15% of the motorists surveyed”

The second criterion establishes the number of accidents per year during the last year along the street as a warrant for traffic calming study.

Accident Penalty

Points

No. of accidents

0.5

1-2

1.0

3

1.5

4 or more

i. Any street that ranks 2.5 or higher merits Traffic Calming upon approval of the City’s Traffic Engineer. The neighborhood street would require 2/3 voter approval from residents and is subject to roadway design. Due to the curvature of the roadway, and other design characteristics, some streets may not be suitable for traffic calming.

ii. Any street that ranks 2.0 should be studied by the Traffic Management Team and the City’s Traffic Engineering Consultant.

The following items may be included in the study:

     1. A review of accident/ crash reports for a three calendar year period. 

        Location of school, pedestrian oriented facility (elderly housing) or community       

        facility  (park) located on the subject street or within an established walking area.

     2. Driveway Density.

     3. Presence/Absence of sidewalks.

After review of the above study, the project must be supported by the City’s Traffic Consultant and the Traffic Management Team. The neighborhood street would require 2/3 voter approval from residents and is subject to roadway design. Due to the curvature of the roadway, and other design characteristics, some streets may not be suitable for traffic calming.

Any street that scores less than a 2.0 and is determined not to be an appropriate location based on the study completed will not be eligible for testing for 12 months after the speed/volume study is conducted. After two years of testing, if the street does not qualify for traffic calming, the project is ineligible for re-testing for 24 months.

3. CHECK FOR CONSISTENCY WITH CITY AND MPO PLANS AND PROGRAMS: Every effort will be made to ensure that any proposed physical traffic modifications will be consistent with City and County short and long range transportation plans and programs. However, this may require recommendations to change the priority of previously adopted plans and programs in order to more rapidly improve the efficiency of the arterial network near the affected neighborhood. In addition, every effort will be made to ensure that any physical traffic modifications are consistent with land use/zoning. The land use within neighborhoods, commercial and industrial areas will be reviewed carefully, and the determining factor for the classification of the road would be the predominant land use.

4. PREPARE THE DRAFT TRAFFIC CALMING PLAN: The engineering team will develop a preliminary set of traffic calming plan for the warranted street, taken into account a number of factors, including: proximity of proposed traffic calming device location relative to driveways, traffic control devices; locations of inlet, manhole, light pole; and any other traffic calming plans proposed for the subject street.

5. SUBMIT PLAN FOR APPROVAL:  The draft plan will be submitted to the Fire Department, Police Department, and the Miami-Dade County for review and comments. Plan may be revised to address any concern expressed by these agencies.

6. CONDUCT NEIGHBORHOOD WORKSHOP: If the area of concern meets the minimum criteria outlined in this document, City staff will schedule a neighborhood workshop meeting with residents to review the results of preliminary studies and to receive comments on the preliminary design of the traffic calming plan.

Citizen participation is an essential ingredient in the development and implementation of a successful neighborhood traffic plan. Neighborhood residents offer insight into the nature and extent of traffic and safety problems. These residents are most directly affected by the problems and potential mitigating measures, and they are frequently the source of innovative solutions. The following are two levels of community involvement:

A. Participatory programs involving community leaders and interested citizens.

B. Outreach programs attempting to communicate with the silent citizens, normally the vast majority of residents.

Implementation of an effective traffic management program, which incorporates resident participation, will provide many benefits to the community. Benefits include effective transportation control, community safety and an enhanced quality of life.

Once the study is complete and a neighborhood meeting has been held, a ballot will be sent to each affected property owner. Approval of at least two-thirds (2/3) of the affected property owners is needed to proceed with the traffic calming plan.

7. PRIORITIZE AND IMPLEMENT PROJECT: Projects are prioritized Citywide based on the point score determined in Step 2, Request Evaluation. The highest-ranking projects are undertaken first. The number of projects initiated each year depends on City resources. The City notifies all project requesters of the status of their request after project approval. The City also notifies the appropriate neighborhood associations or homeowner associations of the status of the neighborhood projects within their neighborhood and asks for their comments.

City staff will finalize the design and implementation process for the proposed traffic calming devices. Specific techniques may be installed as a “test site”, while others will be installed permanently. “Test sites” will be monitored and evaluated for effectiveness. After a period of evaluation, measurable objectives and performance measures will be established on a case by case basis. It is noted that the City’s Traffic Engineering Standards will be consulted for adherence in relation to any proposed traffic calming measures.

8. EVALUATE PROJECT: Immediately following the installation of the project, City staff will begin an evaluation of the project’s effectiveness. This evaluation includes, but is not limited to, field observations, traffic counts, speed studies and other data collection (as needed). If the project has not met the objectives during the evaluation period, staff will notify the community’s representatives. City staff and community representatives may then decide to make modifications to the current plan. These modifications may include the implementation of additional or different techniques, or the removal of the traffic calming devices.

D. Characteristics of Traffic Calming Devices

Traffic calming measures can be separated into two groups based on the main impact intended:

Volume control measures are primarily used to address cut-through traffic problems by blocking certain movements, thereby diverting traffic to streets better able to handle it.

Speed control measures are primarily used to address speeding problems by changing vertical alignment, changing horizontal alignment, or narrowing the roadway. The distinction between the two types of measures is not as clear as their names suggest, since speed control measures frequently divert traffic to alternate routes, and volume control measures usually slow traffic.

Traffic Changes

 

Volume Reductions

Speed Reductions

Noise

Emergency & Service Access

Cost Effectiveness

Speed Humps/Speed Cushions

Possible

Possible

Increase

Some problems

Moderate ($2-$5K)

Raised Crosswalks

No effect

No

No effect

No effect

Moderate ($4K)

Textured Pavements

Unlikely

Yes

Minor change

No effect

Moderate to High (varies)

Traffic Circles

Unclear

Minor

Minor change

Some constraints

Moderate to High

($10-$30K w/o ROW cost)

Chockers/Bump-outs

Rare

Minor

Minor change

No effect

Moderate

($10-$20 per approach)

Short Medians

No

Yes

No effect

No effect

Moderate ($5-$15K)

 

 

 

Statistics Table

Measure

Advantages

Disadvantages

Effectiveness

Speed Hump

  • relatively inexpensive
  • relatively easy for bicycles to cross if designed appropriately
  • very effective in slowing travel speeds.

 

  • cause a “rough ride” for all drivers, and can cause severe pain for people with certain skeletal disabilities
  • force large vehicles, such as emergency vehicles and those with rigid suspensions, to travel at slower speeds
  • may increase noise and air pollution
  • have questionable aesthetics
  • For a 12-foot hump:

Average of 22% decrease in the 85th percentile travel speeds, or from an average of 35.0 to 27.4 miles per hour; (from a sample of 179 sites).  Average of 11% decrease in accidents, or from an average of 2.7 to 2.4 accidents per year (from a sample of 49 sites).

 

  • For a 14-foot hump:

Average of 23% decrease in the 85th percentile travel speeds, or from an average of 33.3 to 25.6 miles per hour (from a sample of 15 sites).  Average of 41% decrease in accidents, or from an average of 4.4 to 2.6 accidents per year (from a sample of 5 sites)

 

Raised Crosswalks

  • improve safety for both pedestrians and vehicles
  • If designed well, they can have positive aesthetic value
  • They are effective in reducing speeds, though not to the extent of Speed Humps 

 

  • can be expensive
  • Their impacts on drainage needs to be considered
  • They may increase noise and air pollution

 

  • For a 22-foot Speed Table (the most similar device for which data is available):
  • Average of 18% decrease in the 85th percentile travel speeds, or from an average of 36.7 to 30.1 miles per hour; (from a sample of 58 sites).
  • Average of 45% decrease in accidents, or from an average of 6.7 to 3.7 accidents per year (from a sample of 8 sites).

 

Textured Pavements

  • can reduce vehicle speeds over an extended length
  • If designed well, they can have positive aesthetic value
  • Placed at an intersection, they can calm two streets at once

 

  • generally expensive, varying by materials used
  • If used on a crosswalk, they can make crossings more difficult for wheelchair users and the visually impaired

 

  • No data has been compiled on the effects of textured pavements

Traffic Circles

  • very effective in moderating speeds and improving safety
  • If designed well, they can have positive aesthetic value
  • Placed at an intersection, they can calm two streets at once

 

  • difficult for large vehicles (such as fire trucks) to circumnavigate
  • must be designed so that the circulating lane does not encroach on the crosswalks
  • may require the elimination of some on-street parking
  • Landscaping must be maintained, either by the residents or by the municipality

 

  • Average of 11% decrease in the 85th percentile travel speeds, or from an average of 34.1 to 30.2 miles per hour (from a sample of 45 sites)
  • Including a large sample from Seattle, an average of 73% decrease in accidents, or from an average of 2.2 to 0.6 accidents per year (from a sample of 130 sites)
  • Excluding the large sample from Seattle, an average of 29% decrease in accidents, or from an average of 5.9 to 4.2 accidents per year (from a sample of 17 sites)

 

Chockers

  • easily negotiable by large vehicles (such as fire trucks)
  • If designed well, they can have positive aesthetic value
  • reduce both speeds and volumes

 

  • Their effect on vehicle speeds is limited by the absence of any vertical or horizontal deflection
  • may require bicyclists to briefly merge with vehicular traffic
  • may require the elimination of some on-street parking

 

  • Average of 7% decrease in the 85th percentile travel speeds, or from an average of 34.9 to 32.3 miles per hour (combined average for various narrowing measures, taken from a sample of 7 sites)

Short Median (Center Island Narrowings)

  • increase pedestrian safety
  • If designed well, they can have positive aesthetic value
  • reduce traffic volumes

 

  • Their speed-reduction effect is somewhat limited by the absence of any vertical or horizontal deflection
  • may require elimination of some on-street parking

 

  • Average of 7% decrease in the 85th percentile travel speeds, or from an average of 34.9 to 32.3 miles per hour (combined average for various narrowing measures, taken from a sample of 7 sites)

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

E. Application form:

Application Form

 

 

TODAY’s DATE:

 

ASSOCIATION:

 

CONTACT NAME:

 

LOCAL ADDRESS:

 

 

 

HOME PHONE:

 

WORK PHONE:

 

WHICH NEIGHBORHOOD STREET(S) ARE OF CONCERN?

_________________________________________________________________

_________________________________________________________________

_________________________________________________________________

WHAT TRAFFIC OR SAFETY CONCERNS HAVE BEEN OBSERVED? (Check all that apply)

Checklist

Speeding

Reckless driving

Cut-through vehicles

Noise

Vehicles not obey traffic control devices (stop signs, signal…)

Other: _________________________________________________________________

_________________________________________________________________

      ______________________________________________________________

 

 

 

 

Other: ____________________________________________________________

__________________________________________________________________

__________________________________________________________________

RETURN COMPLETED APPLICATION TO:

PUBLIC WORKS DEPARTMENT

1700 Convention Center Drive

Miami Beach, FL 33139

ATTENTION: Transportation Division