Methodology

• Billboard locations & permits — the Illinois DOT Outdoor Advertising Control System (OACS), the statewide registry of permitted billboards, clipped to Chicago city limits (1,196 boards).
• Traffic counts — IDOT Annual Average Daily Traffic (AADT), snapped to each board's nearest road segment.
• Demographics — Census ACS median household income and population by tract, joined by point-in-polygon.
• Neighborhood & address — OpenStreetMap/Nominatim reverse geocoding.

Traffic score — percentile rank of AADT among all 1,196 Chicago boards.

Visibility score — a heuristic, not a measurement: highway frontage (85) beats a state route (70) beats a local street (50), penalized if the board sits far from its matched road (a proxy for being set back from traffic rather than genuinely roadside). There's no real height/angle/obstruction data behind this yet.

Demo fit score — blends tract income percentile (60%) and tract population percentile (40%), as an audience-purchasing-power and density proxy.

Composite score & grade — 55% traffic + 20% visibility + 25% demo fit (renormalized to 70/30 traffic/visibility when tract data is missing). Grades: A+ (90+), A (80+), B (70+), C (55+), D (40+), F (below).

Report card — each board page also shows five letter grades so you can see why it scored the way it did. Traffic, Visibility, and Audience are the three composite inputs, graded on the same scale. Value compares the board's price per 1,000 modeled views to the $7 benchmark (A+ at half the benchmark or less, A up to 70%, B up to 90%, C within 10%, D up to 130%, F above). Competition counts other structures within a quarter mile, not counting other faces of the board itself (A for 0-1, B for 2-3, C for 4-6, D for 7-10, F for 11+; A means uncluttered). Value and competition are extra lenses and are not part of the overall score.

Every board's price starts as a modeled estimate — Perch doesn't have real listing prices for most boards yet. The model:

1. Discounts daily traffic by a visibility-derived factor (35%-90%) to approximate effective monthly impressions — not everyone driving past a board actually notices it. Traffic counts come from IDOT, matched to the road a board is permitted along (an interstate board uses the interstate's count, not a nearby side street's). On divided highways only one direction of traffic sees a given board, so the both-way count is halved there.
2. Prices those impressions at a $7 CPM (cost per thousand impressions/month) — calibrated to public Chicago OOH market data, which put Chicago-specific CPMs in a roughly $4.55-$12.62 range with a $7-7.09 average across the sources below.
3. Clamps the result to real monthly price ranges those same sources report by road type: highway-frontage boards price like bulletins ($2,150-$18,000/mo observed), state routes fall between, and local-street boards price like neighborhood/poster signage ($800-$6,450/mo observed) — so the model can't drift into implausible territory even at extreme traffic counts.

Treat every modeled price as a starting point, not a quote, which is why modeled prices appear as a narrow range ($500 wide under $5,000/mo, $1,000 wide above) rather than a single figure; verified prices show the exact quote. The public IDOT permit data doesn't say whether a board is a bulletin or a poster, or whether it's digital, and those drive real prices, so any single board can be off by a wide margin in either direction. Overall, the modeled average across all 1,196 boards lands near the ~$5,500 Chicago average published by Times OOH Media.

Sources used to calibrate the CPM and price-range figures above (accessed August and September 2026):

• AdQuick — How Much Does a Billboard Cost? 2026 Prices & CPM
• Times OOH Media — Chicago Billboard Costs
• View Media OOH — Chicago Billboard Cost & Location Overview
• Blue Line Media — Billboard Advertising in Chicago (published rate ranges: bulletins $4,500-$7,500 per 4 weeks)

Modeled valuation (an implied sale/structure value) is a further step removed from real data: it's annual modeled revenue × a grade-based multiple (4× for F up to 9× for A+). There's no public data on real single-billboard-structure sale prices, so treat this number as a rough placeholder, not an appraisal.

Any board can carry a ✓ Verified price instead — a real quote collected from a board owner or broker, which overrides the model entirely. Most boards don't have one yet.

Perch prices billboards at a $7 CPM (cost per 1,000 impressions/month). For context, here's how that sits against other ad channels — general published benchmarks, not billboard-specific, and real rates vary heavily by market and inventory tier:

Outdoor advertising generally lands cheaper per impression than broadcast or streaming TV, in the same neighborhood as digital display, and pricier than radio — but with the advantage of being always-on, unskippable, and geographically targeted to wherever the board sits.

If you own, lease, or broker any of these boards and want to contribute a real price, use the "Submit data by email" button on that board's detail page or map popup. Submissions are reviewed before they replace the modeled estimate.