Over the 90 days from July 2 through September 29, 2026, the Southern State Parkway logged a crash-record rate 1.7 times that of the Long Island Expressway when driving volume is factored in, according to 511NY records stored by Long Island Traffic and New York State Department of Transportation 2025 Annual Average Daily Traffic data. The raw counts were close — 155 on the Southern State Parkway versus 158 on the Long Island Expressway — but adjusting for traffic volume separates them.
The Southern State Parkway carried 0.57 times the daily vehicle-miles of the Long Island Expressway across its Nassau and Suffolk segments, according to NYSDOT 2025 AADT data, meaning far fewer miles of driving produced almost as many crash records.
Southern State Parkway rate was the highest of the three corridors
At 39.7 crash records per 100 million vehicle-miles, the Southern State Parkway posted the highest traffic-adjusted rate of the three corridors over the July 2–September 29, 2026 window, according to NYSDOT 2025 AADT data and 511NY records stored by Long Island Traffic. The Long Island Expressway recorded 23.1 per 100 million vehicle-miles — the lowest of the three — while the Northern State Parkway came in at 27.6.
Crash records per 100 million vehicle-miles, July 2–September 29, 2026 (511 crash records from Long Island Traffic’s 511NY store; miles and traffic from NYSDOT)
| Corridor | Miles (Nassau and Suffolk) | Average daily traffic (2025, length-weighted) | 511 crash records | Vehicle-miles in window (millions) | Crash records per 100 million vehicle-miles | Crash records per mile |
|---|---|---|---|---|---|---|
| Long Island Expressway | 56.34 | 134,903 | 158 | 684 | 23.1 | 2.8 |
| Southern State Parkway | 31.47 | 137,694 | 155 | 390 | 39.7 | 4.93 |
| Northern State Parkway | 28.91 | 96,234 | 69 | 250.4 | 27.6 | 2.39 |
On a per-mile basis, the Southern State Parkway also led at 4.93 crash records per mile, compared with 2.8 for the Long Island Expressway and 2.39 for the Northern State Parkway, per NYSDOT 2025 AADT data and 511NY records stored by Long Island Traffic.
Nassau segments had higher rates than Suffolk on every corridor
The county-level breakdown shows Nassau segments recorded higher rates than Suffolk segments on all three corridors, according to NYSDOT 2025 AADT data and 511NY records stored by Long Island Traffic. The Southern State Parkway’s Nassau segment posted 43.7 crash records per 100 million vehicle-miles across 16.62 miles, while its Suffolk segment registered 32.5 across 14.85 miles.
On the Long Island Expressway, the Nassau segment reached 35.9 per 100 million vehicle-miles across 15.71 miles, compared with 16.1 for the Suffolk segment across 40.63 miles. The Northern State Parkway’s Nassau segment recorded 31.7 per 100 million vehicle-miles across 16.74 miles; its Suffolk segment recorded 17 across 12.17 miles.
Crash-record rate by county
| Corridor | County | Miles | 511 crash records | Crash records per 100 million vehicle-miles |
|---|---|---|---|---|
| Long Island Expressway | Nassau | 15.71 | 87 | 35.9 |
| Long Island Expressway | Suffolk | 40.63 | 71 | 16.1 |
| Southern State Parkway | Nassau | 16.62 | 110 | 43.7 |
| Southern State Parkway | Suffolk | 14.85 | 45 | 32.5 |
| Northern State Parkway | Nassau | 16.74 | 57 | 31.7 |
| Northern State Parkway | Suffolk | 12.17 | 12 | 17 |
Month-by-month rates held steady on the Southern State Parkway
The Southern State Parkway’s traffic-adjusted rate varied little across the three periods, according to NYSDOT 2025 AADT data and 511NY records stored by Long Island Traffic: 40 crash records per 100 million vehicle-miles in July 2–31, 2026; 39.5 in August 1–31, 2026; and 39.8 in September 1–29, 2026.
The Long Island Expressway showed more movement — 24.1 in July, dropping to 19.5 in August, then rising to 25.9 in September. The Northern State Parkway went from 27.6 in July to 24.3 in August and 31 in September.
Crash records per 100 million vehicle-miles, month by month (each month uses the same NYSDOT daily vehicle-miles)
| Period | LIE | Southern State | Northern State |
|---|---|---|---|
| July 2–31, 2026 | 24.1 | 40 | 27.6 |
| August 1–31, 2026 | 19.5 | 39.5 | 24.3 |
| September 1–29, 2026 | 25.9 | 39.8 | 31 |
Fatal crashes on FARS records, 2020–2024
NHTSA’s Fatality Analysis Reporting System recorded 52 fatal crashes and 63 deaths on the Southern State Parkway’s Nassau and Suffolk portions from 2020 through 2024 (2024 figures preliminary), compared with 51 fatal crashes and 55 deaths on the Long Island Expressway and 14 fatal crashes and 17 deaths on the Northern State Parkway over the same five years. The FARS table is context only and is not divided by traffic volume. See the full Long Island road fatal-crash record, 2010–2024 for additional detail.
Fatal crashes in Nassau and Suffolk, 2020–2024 (FARS; 2024 preliminary)
| Corridor | Fatal crashes | Deaths |
|---|---|---|
| Long Island Expressway | 51 | 55 |
| Southern State Parkway | 52 | 63 |
| Northern State Parkway | 14 | 17 |
How we measured this
- Crash records: 511NY accident-class records titled Crash, Vehicle fire or Overturned vehicle on each corridor in Nassau and Suffolk, stored by Long Island Traffic’s 511NY monitor, reported from 12:00 a.m. July 2 through 11:59 p.m. September 29, 2026 (Eastern). Queens records are excluded.
- Traffic volume: NYSDOT’s 2025 Annual Average Daily Traffic (AADT) for every mainline count-station segment of the corridor in Nassau and Suffolk (ramps excluded; 39 LIE, 32 Southern State and 23 Northern State segments). Divided-highway segments NYSDOT draws once per direction were counted once.
- Vehicle-miles: each segment’s AADT times its length in miles, summed to daily vehicle-miles for the corridor, then multiplied by the number of days in the window.
- Rate: 511 crash records divided by vehicle-miles in the window, expressed per 100 million vehicle-miles. “Average daily traffic” in the tables is the length-weighted average across the corridor’s segments.
- The Southern State figures stop at NY 27 (Exit 44); NYSDOT files the road east of there as the Heckscher State Parkway.
- The FARS table counts fatal crashes and deaths on each corridor’s Nassau and Suffolk portions from NHTSA’s national files; it is context only and is not divided by traffic.
Limitations
- A 511 record is not a verified crash: one collision can produce more than one record, and some crashes never reach 511. These rates compare 511 crash records, not police-reported crash rates.
- The traffic figures are NYSDOT’s 2025 annual averages applied to 2026 records; traffic during this window may differ from the annual average.
- Many AADT values are NYSDOT estimates factored from earlier counts rather than new counts (21 of 39 LIE, 18 of 32 Southern State and 6 of 23 Northern State segments carry an actual 2025 count).
- 90 days of records is a short window; a difference between corridors this size can move from one quarter to the next.
- Whether an incident reaches 511 can differ by road and by the agency that reports it, so part of any difference between corridors may be reporting, not risk.