Urbanicity research · vertical theory
The Transport Hinge
A downtown can only grow upward as far as the networks that feed it allow. This page measures, for every downtown we have mapped, how much of the nation's rail, transit, highway and bridge network actually touches the core, using 54 datasets from the U.S. Department of Transportation's Bureau of Transportation Statistics, read live.
Transit lines and stopsLines reaching downtown set the size of the commuter area; stops near the core are the access that supports density.
Rail and intermodal hubsRail into the core has historically anchored office clusters; places where several modes meet tend to anchor tall development.
Highways and bridgesRoad capacity and crossings show how reachable a river- or harbor-bound core is, and what it depends on.
Fatal crashesCrash density inside the core is the street-safety side of walkability.
Executive summary
- 29 downtown polygons in 20 cities (63.9 square miles) measured against 11 live BTS layers.
- Most transit lines per square mile: Arlington · Crystal City, 108.7 lines per sq mi (50 lines in all).
- Densest stop grid: Boston · Downtown, 284 stops per sq mi.
- Most intermodal passenger hubs: Chicago · Chicago CBD, 134 terminals where modes meet.
- Most highway bridges inside the core: Chicago · Chicago CBD, 137, a measure of how much the downtown depends on crossings.
- Highest fatal-crash rate, 2023: Los Angeles · Downtown, 2.33 per sq mi; the street-safety side of walkability.
- Counts are features that touch each CBD polygon, read live from the U.S. DOT Bureau of Transportation Statistics; small polygons (under a quarter square mile) are left out of the leader lines.
Measured 2026-11-01 · re-measured monthly from geodata.bts.gov
Downtown transport scorecard
| City | Downtown | Sq mi | Transit stops | Transit lines reaching the core | Intermodal passenger hubs | Amtrak stations | Passenger rail segments | National Highway System segments | Highway bridges | Rail grade crossings | Fatal crashes, 2023 (final) | Fatal crashes, 2024 (initial) | Traffic count stations | |
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Arlington | Downtown #21 | 1.9 | 312166.8/mi² | 5428.9/mi² | 4021.4/mi² | 00.0/mi² | 00.0/mi² | 3317.7/mi² | 2010.7/mi² | 00.0/mi² | 10.5/mi² | 00.0/mi² | 00.0/mi² | Map |
| Arlington | Crystal City #22 | 0.5 | 102221.7/mi² | 50108.7/mi² | 919.6/mi² | 00.0/mi² | 00.0/mi² | 715.2/mi² | 919.6/mi² | 00.0/mi² | 00.0/mi² | 00.0/mi² | 00.0/mi² | Map |
| Atlanta | Downtown #19 | 0.9 | 4856.5/mi² | 1821.2/mi² | 89.4/mi² | 00.0/mi² | 00.0/mi² | 2428.2/mi² | 1821.2/mi² | 00.0/mi² | 11.2/mi² | 22.4/mi² | 00.0/mi² | Map |
| Austin | Downtown #29 | 1.0 | 4847.5/mi² | 3837.6/mi² | 2221.8/mi² | 00.0/mi² | 44.0/mi² | 22.0/mi² | 2120.8/mi² | 76.9/mi² | 22.0/mi² | 11.0/mi² | 00.0/mi² | Map |
| Baltimore | Inner Harbor #9 | 0.2 | 72480.0/mi² | 38253.3/mi² | 16.7/mi² | 00.0/mi² | 00.0/mi² | 1280.0/mi² | 00.0/mi² | 00.0/mi² | 00.0/mi² | 16.7/mi² | 00.0/mi² | Map |
| Bethesda | Downtown #25 | 0.6 | 5998.3/mi² | 1220.0/mi² | 1016.7/mi² | 00.0/mi² | 00.0/mi² | 915.0/mi² | 35.0/mi² | 11.7/mi² | 00.0/mi² | 00.0/mi² | 00.0/mi² | Map |
| Boston | Downtown #10 | 2.4 | 690284.0/mi² | 13153.9/mi² | 8233.7/mi² | 31.2/mi² | 229.1/mi² | 271111.5/mi² | 10342.4/mi² | 187.4/mi² | 20.8/mi² | 10.4/mi² | 00.0/mi² | Map |
| Boston | Downtown #11 | 2.1 | 11957.2/mi² | 6028.9/mi² | 3918.8/mi² | 00.0/mi² | 5526.4/mi² | 8038.5/mi² | 5426.0/mi² | 199.1/mi² | 00.0/mi² | 10.5/mi² | 00.0/mi² | Map |
| Chicago | Chicago CBD #2 | 4.2 | 465111.0/mi² | 6716.0/mi² | 13432.0/mi² | 10.2/mi² | 235.5/mi² | 11026.3/mi² | 13732.7/mi² | 6816.2/mi² | 41.0/mi² | 71.7/mi² | 00.0/mi² | Map |
| Chicago | Downtown #8 | 1.7 | 11666.7/mi² | 2112.1/mi² | 2112.1/mi² | 00.0/mi² | 63.5/mi² | 1910.9/mi² | 148.1/mi² | 2916.7/mi² | 10.6/mi² | 31.7/mi² | 00.0/mi² | Map |
| Dallas | Dallas CBD #3 | 5.1 | 29458.2/mi² | 346.7/mi² | 204.0/mi² | 20.4/mi² | 163.2/mi² | 10821.4/mi² | 11222.2/mi² | 418.1/mi² | 112.2/mi² | 153.0/mi² | 00.0/mi² | Map |
| Detroit | Detroit CBD #4 | 3.8 | 440117.0/mi² | 12834.0/mi² | 4612.2/mi² | 00.0/mi² | 00.0/mi² | 10327.4/mi² | 7018.6/mi² | 112.9/mi² | 61.6/mi² | 30.8/mi² | 00.0/mi² | Map |
| Kansas City | KC, KS #30 | 0.2 | 1381.3/mi² | 425.0/mi² | 00.0/mi² | 00.0/mi² | 00.0/mi² | 212.5/mi² | 00.0/mi² | 16.3/mi² | 00.0/mi² | 00.0/mi² | 00.0/mi² | Map |
| Los Angeles | CENTRAL #12 | 5.7 | 1,126198.6/mi² | 8515.0/mi² | 8314.6/mi² | 10.2/mi² | 173.0/mi² | 50889.6/mi² | 7112.5/mi² | 30.5/mi² | 91.6/mi² | 111.9/mi² | 00.0/mi² | Map |
| Los Angeles | ALT-1 #13 | 0.5 | 2650.0/mi² | 1834.6/mi² | 00.0/mi² | 00.0/mi² | 59.6/mi² | 2955.8/mi² | 35.8/mi² | 11.9/mi² | 00.0/mi² | 11.9/mi² | 00.0/mi² | Map |
| Los Angeles | ALT-2 #14 | 4.1 | 31475.9/mi² | 225.3/mi² | 225.3/mi² | 00.0/mi² | 00.0/mi² | 23657.0/mi² | 122.9/mi² | 00.0/mi² | 71.7/mi² | 61.5/mi² | 00.0/mi² | Map |
| Los Angeles | Downtown #15 | 4.5 | 25456.7/mi² | 194.2/mi² | 51.1/mi² | 10.2/mi² | 00.0/mi² | 10723.9/mi² | 408.9/mi² | 00.0/mi² | 20.5/mi² | 30.7/mi² | 00.0/mi² | Map |
| Los Angeles | Downtown #16 | 3.4 | 30488.9/mi² | 247.0/mi² | 216.1/mi² | 00.0/mi² | 00.0/mi² | 12235.7/mi² | 00.0/mi² | 00.0/mi² | 20.6/mi² | 30.9/mi² | 00.0/mi² | Map |
| Los Angeles | Downtown #17 | 0.4 | 2353.5/mi² | 1944.2/mi² | 12.3/mi² | 00.0/mi² | 24.7/mi² | 1637.2/mi² | 1432.6/mi² | 716.3/mi² | 12.3/mi² | 12.3/mi² | 00.0/mi² | Map |
| Manassas | Downtown #26 | 0.1 | 112.5/mi² | 337.5/mi² | 00.0/mi² | 00.0/mi² | 00.0/mi² | 450.0/mi² | 00.0/mi² | 00.0/mi² | 112.5/mi² | 00.0/mi² | 00.0/mi² | Map |
| Miami | Downtown #7 | 2.3 | 19082.3/mi² | 3716.0/mi² | 5021.7/mi² | 00.0/mi² | 00.0/mi² | 5322.9/mi² | 3515.2/mi² | 104.3/mi² | 31.3/mi² | 10.4/mi² | 00.0/mi² | Map |
| Minneapolis | Minneapolis CBD #5 | 4.4 | 39188.3/mi² | 6614.9/mi² | 6715.1/mi² | 00.0/mi² | 40.9/mi² | 112.5/mi² | 8419.0/mi² | 337.5/mi² | 10.2/mi² | 20.5/mi² | 00.0/mi² | Map |
| Nashville | Downtown #18 | 0.4 | 2561.0/mi² | 2458.5/mi² | 922.0/mi² | 00.0/mi² | 12.4/mi² | 3687.8/mi² | 12.4/mi² | 12.4/mi² | 00.0/mi² | 12.4/mi² | 00.0/mi² | Map |
| Rockville | Downtown #27 | 0.0 | 7350.0/mi² | 5250.0/mi² | 00.0/mi² | 00.0/mi² | 00.0/mi² | 00.0/mi² | 00.0/mi² | 00.0/mi² | 00.0/mi² | 00.0/mi² | 00.0/mi² | Map |
| Rockville | Downtown #28 | 5.5 | 20837.8/mi² | 234.2/mi² | 71.3/mi² | 00.0/mi² | 20.4/mi² | 254.6/mi² | 213.8/mi² | 30.6/mi² | 30.6/mi² | 30.6/mi² | 00.0/mi² | Map |
| Silver Spring | Downtown #24 | 0.6 | 137214.1/mi² | 3656.3/mi² | 812.5/mi² | 00.0/mi² | 34.7/mi² | 1117.2/mi² | 23.1/mi² | 46.3/mi² | 00.0/mi² | 11.6/mi² | 00.0/mi² | Map |
| St Louis | St Louis CBD #6 | 2.1 | 11553.7/mi² | 2310.8/mi² | 83.7/mi² | 10.5/mi² | 73.3/mi² | 3014.0/mi² | 2210.3/mi² | 167.5/mi² | 20.9/mi² | 52.3/mi² | 00.0/mi² | Map |
| Tysons | Tysons Corner #20 | 2.4 | 15564.9/mi² | 3916.3/mi² | 198.0/mi² | 00.0/mi² | 00.0/mi² | 2610.9/mi² | 3916.3/mi² | 00.0/mi² | 20.8/mi² | 00.0/mi² | 00.0/mi² | Map |
| Washington | District of Columbia #23 | 3.0 | 732245.6/mi² | 9632.2/mi² | 8729.2/mi² | 00.0/mi² | 10.3/mi² | 10735.9/mi² | 93.0/mi² | 00.0/mi² | 51.7/mi² | 20.7/mi² | 00.0/mi² | Map |
Live map
Dashed outlines are our downtown (CBD) boundaries. Layers are read live from BTS for the area on screen; some appear only once you zoom in.
The 54 BTS datasets
| Top ten | Group | Dataset | Covers | How we use it | Updated | License |
|---|---|---|---|---|---|---|
| 2 | Transit and commute | National Transit Map Stops Stops near the core directly measure transit access, which supports density. |
Public transit stops | Live map layer Scorecard: Transit stops |
2026-10-16 | CC-BY-3.0 |
| 3 | Transit and commute | National Transit Map Routes Lines reaching downtown set the size of the commuter area. |
Public transit routes | Live map layer Scorecard: Transit lines reaching the core |
2026-10-17 | CC-BY-3.0 |
| 4 | Transit and commute | Means of Transportation to Work Transit and walking shares show whether a downtown runs without the car. |
Commute mode by census tract | Live map layer | 2026-04-14 | US gov work |
| 9 | Transit and commute | Travel Time to Work Long commutes to the core push up demand for downtown housing. |
Commute time by census tract | Live map layer | 2026-04-14 | US gov work |
| 10 | Transit and commute | Intermodal Passenger Connectivity Database Hubs where several modes meet tend to anchor tall development. |
About 14,000 passenger terminals | Live map layer Scorecard: Intermodal passenger hubs |
2025-04-30 | US gov work |
| Transit and commute | Adjusted Urban Areas | FHWA urban area boundaries | Live map layer | 2026-06-02 | US gov work | |
| 8 | Rail | NARN Passenger Rail View Rail into the core has historically driven downtown office clusters. |
Passenger rail lines | Live map layer Scorecard: Passenger rail segments |
2026-10-20 | US gov work |
| Rail | Amtrak Routes | Amtrak routes | Live map layer | 2026-05-14 | US gov work | |
| Rail | Amtrak Stations | Amtrak stations | Live map layer Scorecard: Amtrak stations |
2026-10-13 | US gov work | |
| Rail | Hazard Exposure: NARN Lines (beta) | Rail lines exposed to hazards | Live map layer | 2025-10-22 | US gov work | |
| Rail | NARN BNSF View | BNSF lines | Live map layer | 2026-10-20 | US gov work | |
| Rail | NARN Class I Freight View | Class I freight lines | Live map layer | 2026-10-20 | US gov work | |
| Rail | NARN CN View | CN lines | Live map layer | 2026-10-20 | US gov work | |
| Rail | NARN CPKC View | CPKC lines | Live map layer | 2026-10-20 | US gov work | |
| Rail | NARN CSX View | CSX lines | Live map layer | 2026-10-20 | US gov work | |
| Rail | NARN Nodes | Rail junction points | Live map layer | 2026-10-20 | US gov work | |
| Rail | NARN NS View | NS lines | Live map layer | 2026-10-20 | US gov work | |
| Rail | NARN UP View | UP lines | Live map layer | 2026-10-20 | US gov work | |
| Rail | North American Rail Network Lines | Rail lines, US, Canada, Mexico | Live map layer | 2026-10-20 | US gov work | |
| Rail | Rail Mileposts | FRA mileposts | Live map layer | 2025-11-21 | US gov work | |
| Rail | Railroad Grade Crossings | Road and rail crossings at grade | Live map layer Scorecard: Rail grade crossings |
2026-10-20 | US gov work | |
| Rail | Rail Yards | Rail yards | Live map layer | 2026-10-20 | US gov work | |
| Roads | 1991 Federal Aid Primary | 1991 system for billboard control | Live map layer | 2026-07-15 | US gov work | |
| Roads | FAF5 Highway Network Assignments | Freight flows per highway link | Download only · 750 MB | 2025-10-27 | US gov work | |
| Roads | FAF5 Network Links | Freight Analysis Framework network | Live map layer | 2026-07-15 | US gov work | |
| Roads | Hazard Exposure: NHS (beta) | NHS roads exposed to hazards | Live map layer | 2025-10-22 | US gov work | |
| Roads | National Highway Freight Network | Freight highway network | Live map layer | 2026-05-28 | NHFN 2023.02.08 notice | |
| Roads | National Highway Planning Network | FHWA planning network, used with HPMS | Live map layer | 2026-07-15 | US gov work | |
| Roads | National Highway System | NHS network | Live map layer Scorecard: National Highway System segments |
2025-09-03 | NHS 2025.08.08 notice | |
| Roads | National Network | Network for large trucks | Live map layer | 2026-07-15 | US gov work | |
| Roads | North American Roads | Major roads, three countries | Live map layer | 2026-07-15 | US gov work | |
| Roads | Strategic Highway Network | About 64,000 miles of defense highways | Live map layer | 2025-09-04 | NHS 2025.03.27 notice | |
| 5 | Bridges and tunnels | National Bridge Inventory Bridge traffic and condition show how reachable a river- or harbor-bound core is. |
Every highway bridge and its condition | Live map layer Scorecard: Highway bridges |
2025-08-11 | US gov work |
| Bridges and tunnels | Hazard Exposure: NHS Bridges (beta) | NHS bridges exposed to hazards | Live map layer | 2025-10-22 | US gov work | |
| Bridges and tunnels | National Tunnel Inventory | Highway tunnels | Live map layer | 2025-09-04 | US gov work | |
| Bridges and tunnels | NBI Element Data | Inspection data per bridge part | Table (joins to a layer) | 2025-08-19 | US gov work | |
| Bridges and tunnels | NTI Element Data | Inspection data per tunnel part | Table (joins to a layer) | 2025-09-04 | US gov work | |
| Bridges and tunnels | Railroad Bridges | Railroad bridge inventory | Live map layer | 2026-07-15 | US gov work | |
| 1 | Traffic | HPMS 2024 Lanes, road class and daily traffic measure road capacity and demand into each core. |
Road extent, condition and traffic | Download only · 2.62 GB | 2026-09-11 | US gov work |
| 7 | Traffic | TMAS Volume Hourly counts show peak commuter flows and long-run trends. |
Hourly traffic volumes | Download only · 547 MB | 2026-04-20 | US gov work |
| Traffic | HPMS 2020 | HPMS for 2020 | Download only · 6.26 GB | 2026-09-11 | US gov work | |
| Traffic | HPMS 2023 (beta) | Preliminary 2023 HPMS | Download only · 4.35 GB | 2026-09-11 | US gov work | |
| Traffic | TMAS Class | Counts by vehicle type | Download only · 1.57 GB | 2026-04-20 | US gov work | |
| Traffic | TMAS Stations | Permanent count station locations | Live map layer Scorecard: Traffic count stations |
2026-04-17 | US gov work | |
| Traffic | TMAS Stations Table | Details per count station | Download only · 0.76 MB | 2026-04-20 | US gov work | |
| Traffic | Weigh-in-Motion Stations | Stations that weigh trucks in motion | Live map layer | 2025-04-30 | US gov work | |
| 6 | Crashes | FARS 2024 Accidents Crash density near the core measures street safety and walkability. |
Fatal crashes in 2024 | Live map layer Scorecard: Fatal crashes, 2024 (initial) |
2026-07-01 | US gov work |
| Crashes | FARS 2023 Accidents | Fatal crashes in 2023 | Live map layer Scorecard: Fatal crashes, 2023 (final) |
2026-07-06 | US gov work | |
| Crashes | FARS 2023 Accidents Auxiliary | Extra 2023 crash fields | Table (joins to a layer) | 2026-07-06 | US gov work | |
| Crashes | FARS 2023 Person Auxiliary | Extra 2023 person fields | Table (joins to a layer) | 2026-07-06 | US gov work | |
| Crashes | FARS 2023 Vehicle Auxiliary | Extra 2023 vehicle fields | Table (joins to a layer) | 2026-07-06 | US gov work | |
| Crashes | FARS 2024 Accidents Auxiliary | Extra 2024 crash fields | Table (joins to a layer) | 2026-07-06 | US gov work | |
| Crashes | FARS 2024 Person Auxiliary | Extra 2024 person fields | Table (joins to a layer) | 2026-07-06 | US gov work | |
| Crashes | FARS 2024 Vehicle Auxiliary | Extra 2024 vehicle fields | Table (joins to a layer) | 2026-07-06 | US gov work |
Source: U.S. Department of Transportation, Bureau of Transportation Statistics, National Transportation Atlas Database. U.S. government works are public domain; National Transit Map data are licensed CC-BY-3.0. Downtown boundaries: Urbanicity research.
Downtown (CBD) boundaries are Urbanicity's own research polygons. Counts are features touching each polygon, queried from the Bureau of Transportation Statistics' services and refreshed monthly. Scan or share: newschoolworks.com/q/93EJKP · a newSchoolWorks.com research page.