Between August 7 and November 4, 2026, the Long Island Expressway logged 149 crash records in Nassau and Suffolk and the Southern State Parkway logged 134, according to 511NY records stored by Long Island Traffic. The raw counts are close. The traffic-adjusted rates are not.
Measured against New York State Department of Transportation 2025 traffic counts, the Southern State had 38.2 crash records per 100 million vehicle-miles. The Long Island Expressway had 24.2, and the Northern State Parkway had 27.5. NYSDOT-based figures put the Southern State’s rate at 1.6 times the Long Island Expressway’s.
Southern State Parkway has the highest crash-record rate of the three roads
Among the three corridors in this window, the Southern State Parkway had the highest crash-record rate per 100 million vehicle-miles and the Long Island Expressway had the lowest, according to rates built on NYSDOT 2025 Annual Average Daily Traffic data.
The Northern State Parkway logged 62 crash records over the same period, 511NY records stored by Long Island Traffic show. That works out to 27.5 per 100 million vehicle-miles, based on NYSDOT traffic counts.
511NY records stored by Long Island Traffic show the comparison covers 81 days.
Crash records per 100 million vehicle-miles, August 7–November 4, 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 | 149 | 615.6 | 24.2 | 2.64 |
| Southern State Parkway | 31.47 | 137,694 | 134 | 351 | 38.2 | 4.26 |
| Northern State Parkway | 28.91 | 96,234 | 62 | 225.4 | 27.5 | 2.14 |
Live conditions and recent history for each road are on the Southern State Parkway, Long Island Expressway and Northern State Parkway pages.
Fewer records on the Southern State, but on far less driving
The Southern State Parkway’s crash-record count was 0.9 of the Long Island Expressway’s in this window, according to 511NY records stored by Long Island Traffic.
The driving on each road differs more. NYSDOT 2025 data show that the Southern State carries 0.57 of the Long Island Expressway’s daily vehicle-miles.
The Southern State’s length in Nassau and Suffolk is 31.47 miles, according to NYSDOT 2025 count segments. The Long Island Expressway runs 56.34 miles.
Average daily traffic is similar on the two roads. NYSDOT puts it at 137,694 on the Southern State and 134,903 on the Long Island Expressway, length-weighted across each road’s Nassau and Suffolk segments.
The NYSDOT-based table shows 4.26 crash records per mile on the Southern State, 2.64 on the Long Island Expressway and 2.14 on the Northern State. The Southern State figures stop at NY 27 (Exit 44), because NYSDOT files the road east of there as the Heckscher State Parkway.
Nassau rates top Suffolk on all three corridors
On each road, the Nassau stretch had a higher crash-record rate than the Suffolk stretch, according to county figures based on NYSDOT 2025 traffic data:
- Southern State Parkway: 45.1 per 100 million vehicle-miles in Nassau and 25.7 in Suffolk.
- Long Island Expressway: 35.3 in Nassau and 18.1 in Suffolk.
- Northern State Parkway: 30.3 in Nassau and 20.5 in Suffolk.
The Southern State’s Nassau portion logged 102 crash records over 16.62 miles, according to the county table. That is the highest rate in that table.
Crash-record rate by county
| Corridor | County | Miles | 511 crash records | Crash records per 100 million vehicle-miles |
|---|---|---|---|---|
| Long Island Expressway | Nassau | 15.71 | 77 | 35.3 |
| Long Island Expressway | Suffolk | 40.63 | 72 | 18.1 |
| Southern State Parkway | Nassau | 16.62 | 102 | 45.1 |
| Southern State Parkway | Suffolk | 14.85 | 32 | 25.7 |
| Northern State Parkway | Nassau | 16.74 | 49 | 30.3 |
| Northern State Parkway | Suffolk | 12.17 | 13 | 20.5 |
Southern State led in August, September and October
The month-by-month rates based on NYSDOT traffic counts show the Southern State Parkway with the highest rate of the three roads in each full month of the window:
- August 7–31: 41.1, compared with 20 on the Long Island Expressway and 26.6 on the Northern State.
- September: 39.3, compared with 26.3 and 30.6.
- October: 35, compared with 24.9 and 26.6.
Each month uses the same NYSDOT daily vehicle-miles. Long Island Traffic began reading 511NY’s new system on October 2, 2026.
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 |
|---|---|---|---|
| August 7–31, 2026 | 20 | 41.1 | 26.6 |
| September 1–30, 2026 | 26.3 | 39.3 | 30.6 |
| October 1–31, 2026 | 24.9 | 35 | 26.6 |
Fatal crashes from 2020 to 2024 put the Southern State and LIE close
NHTSA’s Fatality Analysis Reporting System counts 52 fatal crashes and 63 deaths on the Southern State Parkway’s Nassau and Suffolk portions from 2020 to 2024. It counts 51 fatal crashes and 55 deaths on the Long Island Expressway.
The same FARS files show 14 fatal crashes and 17 deaths on the Northern State Parkway. The 2024 figures are preliminary, and the FARS counts are not divided by traffic.
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 |
The longer record is in Long Island Traffic’s Long Island road fatal-crash record, 2010–2024.
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. August 7 through 11:59 p.m. November 4, 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).
- 81 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.
- 511NY data was missing or incomplete on Aug 13, 2026, Aug 15, 2026, Sep 4, 2026, Sep 7, 2026, Sep 30, 2026, Oct 1, 2026, Oct 2, 2026, Oct 4, 2026, Oct 24, 2026 (a 511NY outage or capture gap); those 9 days are excluded, and all per-day and per-mile figures use the remaining 81 days.
- Long Island Traffic began reading 511NY’s new system on October 2, 2026. Records before and after that date come from different versions of the 511NY feed, and whether the two record incidents at the same rate has not yet been measured, so a change across that date may partly reflect the switch.