In 2010, the City executed an Interlocal Agreement with Miami-Dade County which approved and adopted a traffic calming analysis methodology and manual for the City. The Miami Beach Traffic Calming Manual establishes criteria that is more contextual to residential neighborhoods and less stringent than the criteria established in the Miami-Dade County Traffic Flow Modification Manual. The City’s Traffic Calming Manual establishes a point system based on the 85th percentile speed, vehicular volumes, and traffic accidents, as further described below:
Points
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85th speed is above posted speed limit
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Points
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Volume 23 hr.
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0.5
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Less than 4.6 mph
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0.5
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500 – 750 veh.
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1.0
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4.6 to 7.5 mph
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1.0
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751 – 1,100 veh.
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1.5
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7.6 to 10.5 mph
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1.5
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1,101 – 1,700 veh.
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2.0
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10.06 to 13.5 mph
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2.0
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1,701 – 2,300 veh.
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2.5
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13.6 to 16.5 mph
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2.5
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More than 2,300 veh.
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3.0
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More than 16.5 mph
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Points
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No. of Accidents
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0.5
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1 – 2
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1.0
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3
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1.5
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4 or more
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Per the City’s Traffic Calming Manual, any roadway segment scoring above 2.5 points is eligible for traffic calming improvements. Segments scoring between 2.0 and 2.5 points are not eligible for traffic calming but should be further studied to determine if alternative mitigation measures would be beneficial.
Based on the data collected, the vehicular speeds along South Shore Drive in the vicinity of Jones Street exceeded the posted speed limit of 25 MPH. The other two locations where data was collected did not exceed the posted speed limit and therefore would not qualify for traffic calming. Transportation and Mobility Department staff evaluated this segment further based on the criteria and point system established in the Traffic Calming Manual and determined the following:
- 85th Percentile Speed: 4 MPH above the posted speed limit – 0.5 points
- Average Daily Traffic Volume: 1,046 vehicles per weekday – 1.0 point
- Vehicular Crashes: 1 crash occurred within the last 5 years – 0.5 points
Based on the evaluation criteria and scoring, South Shore Drive in the vicinity of Jones Street totals 2.0 points; thus, traffic calming is not warranted at this time.
Additional Considerations
Based on site inspections, staff believes that the existing multiple driveways would create conflicts for the strategic placement of speed cushions or speed tables along the corridor, thus making these devices not only not warranted but also unfeasible. Furthermore, staff reviewed the intersections along the corridor and found that it is highly unlikely that all-way stop controls would be warranted since all side streets are dead-ends with very low traffic volumes.
Based on the data collected and the field reviews conducted, staff recommends the installation of six (6) additional 25 MPH speed limit signs and striping “25 MPH” on the roadway pavement (attachment). These improvements would take approximately 60 days to complete and would be funded from the Transportation and Mobility Department’s adopted Fiscal Year 2021/2022 operating budget. Furthermore, staff recommends that additional traffic data be collected along South Shore Drive in the vicinity of Jones Street approximately 90 days following the completion of these improvements to determine if the signage and striping enhancements are effective or if further action is necessary.