Speed Limit Reduction January 24, 2017
History Dating back to 2001 the City Commission has discussed lowering the speed limit in certain areas to 25 mph in response to residential concerns. In May of 2015 the City Commission directed to staff to begin analyzing objective data to determine if the lowering of the speed limit was warranted. In April of 2016 staff submitted the analysis to Miami-Dade County Department of Transportation and Public Works recommending a 25 mph speed limit on all residential streets. In July of 2016 the Miami-Dade County approved the request to lower the speed limit to 25 mph only on residential local roads maintained by the City.
Considerations 48% of all traffic related concerns from 2012-2016 to Public Works were related to speeding The data does not support excessive speed as defined by engineering standards excessive speed is dependent upon the posted speed If the speed limit was posted at 45 mph, and drivers were traveling 45 mph, there would not be a speeding problem
Considerations Pedestrian Safety When drivers are going 25 mph, rather than 30 mph, drivers and pedestrians have more time to see each other and react. Coral Gables PD issue citations beginning at 37 mph Traveling at 40 mph, the average driver who sees a pedestrian in the road 100 feet ahead will still be traveling 38 mph on impact; driving at 25 mph, the driver will have stopped before the pedestrian is struck (Victoria Transport Policy Institute, 1999)
Considerations Pedestrian Safety In a vehicle-pedestrian crash, injury increases significantly as the vehicle speed increases. Speed Chance of Severe Injury 16 mph 10% 23 mph 25% 31 mph 50% 39 mph 75% 46 mph 90% (AAA Foundation for Traffic Safety, 2011)
Considerations Pedestrian Safety The first quarter of FY 2017 saw 11 pedestrian crashes/injuries and 7 bicycle crashes/injuries total 18 injuries 5 of the 18 injuries occurred in the proposed 25 mph zones That number increases to 11 on any local road, i.e. central business district The strategic plan goal is less than 27 pedestrian and less than 26 bike injuries if we continue in this direction, we will fail to meet our goals, surpassing last year s pedestrian injuries
Considerations Enforcement Based on complaints, residents do not feel safe at 30mph, add to that, we do not enforce until drivers reach 37mph The Police Department will be better positioned to enforce the new speed limit with the hiring of 3PTE Results from pilot projects in Springfield and Columbia, Missouri, showed that in all of the streets where the posted speed limit was reduced from 30 mph to 25 mph, there was a statistically significant reduction in average speeds. In Springfield, a spillover effect was observed where speed reductions resulted on adjacent streets where the speed limit was not reduced. (The Open Transportation Journal, 2012)
Considerations Commute Times Average speeds that decline from 30 mph (2:00 minutes per mile) to 25 mph (2:24 minutes per mile) are estimated to add 24 seconds to each mile traveled (Victoria Transport Policy Institute, 1999). based on the above calculation, if it takes half a mile to leave the residential neighborhood, the reduced speed limit of 25 mph would add 12 seconds to an average commute, all else being equal. Travel time is primarily determined by factors like traffic signals, congestion, and turning vehicles. A lower speed limit will not impact speeds during the most congested times of day, when many drivers already travel at speeds below 25 mph (City of Boston and New York City their research on a citywide 25 mph speed limit).
Considerations Road Environment In order to maximize the effectiveness of any existing or newly implemented speed limit, the road environment should be designed to fit the designated speed limit, while enforcement and road safety advertising campaigns should be integrated (Monash University Accident Research Centre, 2008) The majority of drivers do not consider posted speed limits to be the maximum driving speed, but rather a recommended driving speed, and many view driving approximately 3 6 miles per hour over the posted speed limit as acceptable behavior (EKOS Research Associates Inc., 2005) If a road and its posted speed limit are mismatched, lowering the posted speed limit may not result in a reduced driving speed, as drivers tend to respond poorly to such interventions (Journal of Epidemiology and Community Health, 2003)
Next Steps Ordinance for second reading Enter into Intergovernmental Agency Agreement Within 30 days, begin education campaign Replace existing 30mph speed limit on residential streets with 25 mph signs Begin enforcement, 1 month of warnings
Public Engagement E-news Miami Herald CGTV Community Newspapers Gables Central Facebook Pace Car Program
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