Estimating Annual Waste Tire Generation, Diversion and Disposal in California A study for the California Integrated Waste Management Board Shawn Blosser Matthew Newman Trisha McMahon Rob Wassmer Presented By:

Building A Model Review of Estimation Methods in Use Evaluation of Competing Methods Model Overview Data and Parameters Used Results Diversion & Disposal ReviewEvaluationModelDataResultsDiversion

Estimating States Contacted all other 49 states # States States With Waste Tire Generation Estimates37 States Without Waste Tire Generation Estimates12 Total49 Alabama, Delaware, Massachusetts, and Wisconsin do not track waste tire generation but are aware of the one tire per person per year metric. These states are reflected in the "states without waste tire generation estimates" category. ReviewEvaluationModelDataResultsDiversion

Per Capita Standard is Widespread Over half used standard of 1 tire per person # States States Using Unknown Methodologies2 States Using 1 Tire/Person/Year23 States Using Other Methodologies12 Total 37 Missouri and Nevada are counted in other methodologies even though they compare to 1 tire per person ReviewEvaluationModelDataResultsDiversion Maryland, Vermont, and Wyoming methodologies may represent the use of one tire per person per year. Additional detail on these methodologies could not be obtained.

Three Other Methods In Use New tire sales, waste tires received, state models Methodology# StatesState(s) Track Revenues Collected on Tire Sales4 MO, NV, OK, VA Track Waste Tires Collected5 AZ, HI, NC, OH, TN Industry Survey1SC State-Created Model Estimate2FL, WA Total12 Oklahoma appears in track revenues, but it also tracks waste collected. ReviewEvaluationModelDataResultsDiversion

Basis of Per Capita Metrics Rubber Manufacturers Association (RMA) standard of 1 tire per person Replacement tire sales + Tires on scrapped vehicles = million in million/ million people =1.01 PTEs per person/year Asked states to report waste tire generation: million ≈ 1.01 PTEs per person/year. ReviewEvaluationModelDataResultsDiversion

Per Capita Metrics Are Underestimations Does not account for variation in tire weights and sizes Relies on self-fulfilling survey: 1 tire/person/year standard adopted by EPA At least 20 states use the metric as their sole estimation methodology ReviewEvaluationModelDataResultsDiversion

Tracking Tire Fee Revenue Is Not Accurate Underestimates: Captures just one of many flows of waste tires net migration, internet sales, net imports, illegal tire sales, industrial waste May not vary by tire size Oversimplifies: Weights/sizes/characteristics of tires sold change over time May not count government vehicles ReviewEvaluationModelDataResultsDiversion

Two States Use Custom Models Existing models oversimplify: Florida model based on tire fees Washington based on vehicle registration Do not account for other tire flows Ignore the rate at which tires enter the waste stream ReviewEvaluationModelDataResultsDiversion

What Should A Model Do? Fully incorporate all tire flows Track tires over their lifespan Account for variations in tire weights Be flexible, state-specific, modifiable, and updatable ReviewEvaluationModelDataResultsDiversion

What Does Our Model Do? 1. Calculates the number of new tires sold in or entering the state every year 2. Assigns these tires to tire categories by weight 3. Estimates the length of time before they enter the waste stream 4. Tabulates the weight of these waste tires 5. Computes the results in PTEs and Tons ReviewEvaluationModelDataResultsDiversion

Passenger Vehicles Autos, SUVs, Pick-ups, Vans, Motorcycles Light Trucks Cargo trucks, 2- axle trucks, etc. Medium Trucks Semis & trailers Heavy Trucks Garbage trucks, etc. Off-Road Vehicles Construction and farm equipment CA Tires “On the Road” Tires Entering CA Waste Tires Re-Treading Medium & Heavy Truck Tires Only NEW TIRES USED TIRES Annual Industry Sales Data (U.S.) Breakdown of Estimated Tires “on the road” for that year Model estimates that tires enter waste stream by category based on either (1) annual miles driven and tire life expressed in miles, or (2) industry estimates of tire life expressed in years Waste Tires expressed in 20 lb. PTEs (Passenger Tire Equivalents) Rubber waste from re- treading Avg. weight per tire calculated by category using seller, manufacturer, or industry standards. Passenger reflects CA registration in a year. Assigned to Tire Categories based on… Passenger Vehicles Light Trucks Medium Trucks Heavy Trucks Off-Road Vehicles BOE Sales Data New Tires Sales Not Included in BOE Data (Internet, etc.) Net Population Migration from Census ReviewEvaluationModelDataResultsDiversion

Overview of Model Parameters New Tires: # of New Tires Sold: BOE Revenue # of Tires Sold on Internet: Modern Tire Dealer # of Tires Sold to government entities: Federal Highway Administration, CA registration stats. # of Tires Brought in from Out-of-State: Net migration, # of people per HH, # of vehicles per HH Tire Life: VMT for Passenger, Light Truck and Medium Truck: Federal Highway Administration Tread life for all types: National Highway Traffic Safety Administration # of Retreads for all types: Tire Retread Information Bureau Annual maximum life: Industry recommendations, RMA Tire Allocations: # in Passenger, Light Truck, Medium Truck, Heavy Truck, Off-Road: US Sales Distribution Statistics Average Tire Weight: Passenger: Tire Size Sale Statistics, Distributor Specifications, CA vehicle registration Light Truck: Tire Size Sale Statistics, Distributor Specifications Medium Truck: Manufacturer Specifications Heavy Truck, Off-Road: Scrap Tire reports % difference from new weight: CSUS survey, RMA, UK Environment Agency report. ReviewEvaluationModelDataResultsDiversion

Step 1: Calculate the Number of New Tires in CA Our analysis shows that net imports, industrial waste, and illegal sales are insignificant sources of waste tires.  New tire sales in CA  New tire sales from out-of- state  Partially-used tires from net migration ReviewEvaluationModelDataResultsDiversion

Step 2: Assign New Tires to Categories Passenger Vehicles Autos, Vans, SUVs, Pick-ups, Motorcycles P-metric tires Light Trucks 2-axle, single-frame trucks with 6 or more tires LT sized, smaller than 8.25” x 20” Medium Trucks Semi-Trucks and Trailers, etc. Tires sized 8.25” x 20” to 11” x 24.5” Heavy Trucks Garbage Trucks, etc. Tires sized 11” x 24.5” to 14” x 25” Off-Road Vehicles Construction and Farm Equipment Tires sized 16” x 20.5” and larger, plus farm equipment tires ReviewEvaluationModelDataResultsDiversion

Step 3: Estimate the Length of Time Tires are on the Road Function of tire tread life, vehicle miles traveled (VMT), retreading, and time. Tire Category Tire Wear: Tread Life / VMT Time: 6 years Retread Passenger YesYes*No Light truck YesYes*No Medium truck Yes Heavy Truck NoYes Off Road NoYes ReviewEvaluationModelDataResultsDiversion *Tires wear out from use before 6 year limit is reached.

Step 4: Tabulate the Weight of a Scrap Tire Calculated new tire weights for passenger, light truck, and medium truck tires Based on most popular tire sizes for passenger and light truck, on popular brands for medium truck Passenger average was weighted by registration data Adjusted to reflect weight loss due to wear Estimated heavy and off-road tires based on industry data ReviewEvaluationModelDataResultsDiversion

Step 5: Compute the Results Follow tire cohort over the years Estimate the number of tires that become waste each year Sum waste tires Divide by the Passenger Tire Equivalent (PTE) ReviewEvaluationModelDataResultsDiversion

Results Average PTEs/person during 2005 – 2009: 1.24 Average total number of waste tires generated per year during : 46 million PTEs ReviewEvaluationModelDataResultsDiversion

Average PTE/Capita ReviewEvaluationModelDataResultsDiversion

Sources of Waste Tires ReviewEvaluationModelDataResultsDiversion Average for 2005 to 2009 period.

The Variables that Drive Waste Estimates Sales of new tires Average weight of tires/percent lost to wear Composition of vehicle fleet Extent of retreading ReviewEvaluationModelDataResultsDiversion

Model Results Subject to Uncertainty Range when average tire weight varies ±10% Low: 1.12 Best: 1.24 High: 1.37 ReviewEvaluationModelDataResultsDiversion

Diversion & Disposal 2005 CIWMB estimate: 30.6 million diverted, 40.8 generated 75% diversion rate Estimate segment of the market not included in survey Assume similar to those included with 75% diverted Use model generation estimate → 33.6 million diverted RMA Estimates 67.99% diverted in CA National average rate is 86.6% ReviewEvaluationModelDataResultsDiversion