Executive Summary

Illinois currently charges a flat $151 annual registration fee for all passenger vehicles, regardless of weight. This analysis examines the potential for implementing a progressive weight-based fee structure similar to Washington D.C.’s successful 2023 program.

This analysis recommends a moderate progressive schedule that:

Motivation

Illinois roads carry ever-larger vehicles whose mass and height raise the stakes of every crash. Over the last 30 years the average U.S. passenger vehicle has gained roughly 8 inches in height and 1,000 lb in curb weight (IIHS), while battery-electric models such as the GMC Hummer EV tip the scales at about 9,000 lb—nearly twice the weight of a Honda Civic.

These extra pounds and inches aren’t just cosmetic:

  1. Crash lethality scales with size & mass – A National Bureau of Economic Research analysis finds that each additional 1,000lb raises the odds a crash will kill someone by 47%.

  2. Blunt, high hoods amplify pedestrian danger – New research matching detailed crash data to vehicle dimensions shows that every 10 cm increase in front-end height ups pedestrian fatality risk by 22%, and that reducing the size could spare ≈ 500 American lives per year.

  3. Heavier vehicles are polluting vehicles – EPA’s Automotive Trends 2022 report shows that a 5,500lb 2021-model car emits ≈ 40% more CO₂ per mile than a sub-3,000lb car. The IEA calculates that surging SUV sales (avg. curb weight ≈ 2t) drove >20% of the global growth in energy-related CO₂ in 2023.

Why a Weight-Based Registration Fee

Illinois already indexes fees for commercial and farm trucks to weight, but every passenger vehicle—from a 2,700lb Honda Civic to a 9,000lb truck pays the same $151 annual tag (625 ILCS 5/3‑806).

A sliding fee tied to curb weight should be considered for the following reasons:

  1. Internalize externalities – motorists of heavier vehicles would pay more for the risk they pose for deadly crashes, increased carbon emissions, and road damage.

  2. Nudge the market toward lighter, lower-risk models (and lower-emission powertrains).

  3. Fund safer alternatives – revenue can be earmarked for transit, walking, and cycling projects that reduce dependence on over-sized cars.

  4. It’s a progressive tax - Heavier vehicles are largely purchased by higher-income households. And because car-free households (who skew lower-income) pay nothing at all, the fee’s effective burden rises with the ability to pay.

  5. It’s easy to administer - Fee collection is fully digital: the DMV decodes each VIN, pulls the manufacturer’s shipping weight from NHTSA’s VIN decoder database, and assigns the bracket. No weigh‑ins or roadside stops required.

Weight-based fees are not new

Over a dozen jurisdictions levy a progressive vehicle weight fee (USDOT). Washington D.C. has the most aggressive schedule, which was recently implemented in 2023. Here are a few of those fee schedules:

Case Study: How did Washington D.C. implement weight-based fees?

How the program works

  1. Automatic VIN decoding - Owners renew online or at a kiosk; the DMV pulls the manufacturer’s shipping weight from NHTSA’s VIN database and assigns the bracket in real time—no scales, no paperwork.

  2. Revenue & earmarks - The Chief Financial Officer forecast $2.1 million in the first partial year and $9 million per year once fully phased-in. Council language directs the money to sidewalk, school-zone safety and Vision Zero projects, linking the fee to the harms it is meant to offset.

  3. Equity guard-rails - <3,500lb cars (about 48% of the fleet) saw no increase; heavier-vehicle owners—who on average have higher incomes—pay the surcharge. Critics argued the jump from $175 → $250 in the mid-weight tier could sting working families, but the Council’s fiscal note found the median increase city-wide was $60/year (DC DMV).

  4. Complementary policies - The fee joins a suite of “blunt but simple” price signals—graduated residential parking permits, higher ticket fines for repeat scofflaws, and automated speed-camera expansions—meant to push the city toward its Vision Zero and climate goals (DC CFO).

Early lessons

  • Earmark visibly - D.C. linked dollars from heavier vehicles directly to safety projects; polling shows that tying the fee to safer streets blunted opposition.
  • Leverage existing data feeds - Because NHTSA’s VIN decoder is already public, Illinois SOS could replicate D.C.’s fully digital workflow with minimal IT lift.

What could a weight-based fee look like in Illinois?

Illinois had 7,783,284 active passenger vehicle registrations as of May 30th 2025 (ILSOS), and all internal combustion vehicles pay a flat $151 tag. To see what a progressive schedule might raise, we need two things: (1) today’s fleet weight mix and (2) a set of possible fee tables.

Fleet-weight distribution

EPA’s 2024 Automotive Trends report publishes production shares by inertia-weight class (≈ curb-weight + 300lb). Vehicles have become significantly heavier over the past 20 years.

We treat the MY-2023 distribution as a reasonable proxy for the on-road fleet and collapse it into six 1,000-lb-wide bins. Keep in mind, this is an estimate that will not match the actual distribution in Illinois. The Illinois Secretary of State has access to VINs, which would allow the office to make a precise distribution.

Estimated Illinois Light-Duty Fleet Distribution by Weight
Weight Range Estimated Vehicles Fleet Share
≤ 3,000 lb 1,945,821 25%
3,001–3,999 2,334,985 30%
4,000–4,999 1,945,821 25%
5,000–5,999 933,994 12%
6,000–6,999 389,164 5%
7,000–10,000 233,499 3%
Estimated using EPA 2024 Automotive Trends report production shares. Actual Illinois fleet distribution may vary. ILSOS may have shipping weight available for active registrations.

Modeling progressive fee schedules

All scenarios maintain the statutory $151 fee up to 3,000 lb and implement progressive increases for heavier vehicles. We model two approaches with different slopes:

Proposed Progressive Fee Schedules for Illinois
Weight Range Current Moderate Steep Moderate Δ Steep Δ
≤ 3,000 lb 151 151 151 0 0
3,001–3,999 151 200 225 49 74
4,000–4,999 151 250 300 99 149
5,000–5,999 151 325 400 174 249
6,000–6,999 151 450 500 299 349
7,000–10,000 151 600 600 449 449
All fees shown are annual amounts. Increases show additional cost above current $151 flat fee.

Revenue analysis

Revenue Impact of Progressive Weight-Based Fees
Fee Structure Total Annual Revenue Est. Additional Revenue % Increase
Current (Flat $151) $1,175M $0 0%
Moderate Progressive $1,866M $691M +58.8%
Steep Progressive $2,111M $936M +79.6%

Based on 7,783,284 registered passenger vehicles in Illinois as of May 2025.

Progressive impact analysis

The weight-based fee structure creates a progressive tax system where higher-income households—who typically own heavier vehicles—bear a greater share of the burden:

Progressive Impact: Moderate Fee Schedule
Weight Range Vehicles New Fee Increase Est. Additional Revenue
≤ 3,000 lb 1,945,821 $151 $0 $0
3,001–3,999 2,334,985 $200 +$49 $114.4M
4,000–4,999 1,945,821 $250 +$99 $192.6M
5,000–5,999 933,994 $325 +$174 $162.5M
6,000–6,999 389,164 $450 +$299 $116.4M
7,000–10,000 233,499 $600 +$449 $104.8M
Total 7,783,284 $690.8M
Progressive Feature: Vehicles ≤ 4,000lbs see minimal increases

Conclusion

The progressive nature of the fee structure creates a politically viable path forward. A majority of vehicle owners likely see minimal increases, and higher fees apply primarily to luxury vehicles. In order to be politically viable, revenue should directly fund popular safety and infrastructure improvements, and alternatives to driving like mass transit.

Next Steps

The path forward requires careful implementation to achieve the full potential of weight-based vehicle registration fees in Illinois. With proper execution, this policy can simultaneously advance equity, safety, environmental, and fiscal objectives while providing a model for other states to follow.