Reduced Mowing

In a recent report, it was concluded that FDOT could reduce right-of-way (ROW) vegetation management costs by 30% simply by implementing sustainable management practices such as reduced mowing.  Moreover, it was conservatively estimated that roadside vegetation along the state highway system would provide about provide about $1 billion of ecosystem services if sustainable vegetation management practices were implemented. That value would increase to $1.5 billion if wildflower areas were incorporated into roadside ROWs along with sustainable vegetation management practices.

Jeff Caster, State Transportation Landscape Architect, presented the findings of that report at the May 2014 FDOT Executive Workshop. He went on to propose a 10% reduction in mowing – area and/or frequency – and noted that some rural roadsides can be mowed less without impacting safety or operation of the roadway (for example, see Madison County Case Study below).  Jeff also pointed out that a 10% reduction in mowing along rural roads (excluding asset maintenance) can reduce the department’s annual expenditures for mowing by $1,265,597.  The recommendation accepted during the meeting was:

Each District develop and implement a plan to reduce mowing area and frequency (or combination) by 10%

Monitor roadside conditions for one year and revise plan as needed

Monitor for a second year and revise plan as needed

Using lesson learned, amend the Turf Management Guide

Understanding the varying roadside conditions, obligations, and abilities of the Districts, former Secretary Prasad challenged Districts to reduce mowing by 10%, suggesting that Districts work with Jeff Caster to develop strategies and determine best locations to reduce mowing.

Case Study, I-10 Madison County

In 2009, a 4-year study was initiated, in cooperation with the Central Maintenance Office and the District Perry Maintenance Office, to evaluate the effects of decreased clear zone mowing in an effort to reduce expenses and conserve energy.

Clear zones are the relatively flat unobstructed rights-of-way located on the outside of undivided roadways and the inside and outside of divided highways. Clear zones provide a safe place for motorists to pull over to regain control of the vehicle during an emergency. Vegetation established in the clear zone is selected and managed to stabilize the soil and reduce erosion potential, thereby providing a safe haven for vehicles that leave the pavement. FDOT procedures require periodic mowing of the clear zone. Mowing is intended to reduce undesirable weed growth and encourage dense turf cover, which is believed to help stabilize the soil and reduce erosion potential.

The test site was a 1-mile segment of I-10 at the west end of Madison County. Only 10- to 15-foot safety strips adjacent to the inside and outside lanes of pavement were mowed normally, and the entire clear zones (36 foot width or greater) were mowed once in the fall. After 4 years, there were no adverse impacts regarding erosion, safety, aesthetics, or turf quality. Moreover, the modified mowing regime enhanced the overall roadside aesthetics in the spring due to an apparent increase in the occurrence and density of native wildflowers. To view the final report, click on this link:

Madison County Energy Conservation Study - 2012-2013 Survey of Roadside Vegetation Final Report

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