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Interstate 495
Fatal crashes 2015–2024 148Deaths 164Counties 6Latest data year 2024
FARS data are based on police crash reports and other sources; the drunk-driving measure is based on the highest BAC of any driver in the crash. Latest data year: 2024. The route is the trafficway recorded for each crash (FARS TWAY_ID); the same route number in another state has its own page.
Interstate 495 in Massachusetts was the trafficway in 148 fatal crashes between 2015 and 2024, in which 164 people died.
That is 4.2% of the 3,483 fatal crashes in Massachusetts over the same years. The ten-year crash count rose 9% from 136 in 2005–2014 to 148 in 2015–2024.
The crashes were concentrated in Middlesex County (41), Essex County (32) and Bristol County (22) and 3 other counties.
32.4% of the crashes had a driver reported as drinking (Massachusetts: 29.7%) and 33.8% had a speeding-related driver (29.2%); pedestrians were 4.9% and motorcyclists 4.9% of those killed.
Fatal crashes per year
Route identification in FARS is consistent from 2000; earlier years are not shown. Shaded band: the ten-year window used for the shares below.
Compared with all fatal crashes in Massachusetts
| Measure | Interstate 495 | Massachusetts |
|---|---|---|
| Fatal crashes, 2015–2024 | 148 | 3,483 |
| Deaths, 2015–2024 | 164 | 3,665 |
| Deaths per fatal crash | 1.1 | 1.1 |
| Share of state fatal crashes | 4.2% | 100% |
| Change vs previous ten years | +9% | -3% |
Factor shares
Counties along the route
| # | County | Fatal crashes on I-495 | Share of route | County total, all roads |
|---|---|---|---|---|
| 1 | Middlesex County | 41 | 28% | 499 |
| 2 | Essex County | 32 | 22% | 322 |
| 3 | Bristol County | 22 | 15% | 403 |
| 4 | Plymouth County | 20 | 14% | 349 |
| 5 | Worcester County | 17 | 11% | 497 |
| 6 | Norfolk County | 16 | 11% | 350 |
Hour of day
Share of fatal crashes on Interstate 495 beginning in each hour, 2015–2024; tick marks the Massachusetts share for all roads.
Where along the route
| Mile marker range | Fatal crashes | Share |
|---|---|---|
| Mile 25–30 | 7 | 5% |
| Mile 85–90 | 7 | 5% |
| Mile 5–10 | 6 | 4% |
| Mile 0–5 | 5 | 3% |
| Mile 20–25 | 4 | 3% |
| Mile 45–50 | 4 | 3% |
Five-mile bins by FARS milepoint, the six with the most fatal crashes; 52% of crashes on the route have a milepoint. Milepoints are as recorded by the state and can restart at county or district lines.
Other routes in Massachusetts
- Interstate 95 88
- Interstate 90 83
- Interstate 93 77
- US Route 20 74
- State Route 28 72
- State Route 24 58
- Interstate 195 51
- State Route 9 48
- US Route 6 48
- US Route 1 45
- State Route 140 44
- State Route 2 40
All routes and counties in Massachusetts
Questions and answers
How many fatal crashes have there been on Interstate 495 in Massachusetts?
148 fatal crashes with 164 deaths over 2015–2024, per NHTSA's FARS. The route is the trafficway recorded for the crash; the same numbered route in another state has its own page.
Which counties along Interstate 495 had the most fatal crashes?
Middlesex County (41), Essex County (32), Bristol County (22), Plymouth County (20) and Worcester County (17).
What share of crashes on Interstate 495 involved alcohol or speeding?
32.4% had a driver reported as drinking and 33.8% a speeding-related driver, against 29.7% and 29.2% for all fatal crashes in Massachusetts.
When do fatal crashes happen on Interstate 495?
52.7% of the crashes were between 6pm and 6am. The hour chart on this page shows the full distribution.
Provenance
Source: NHTSA Fatality Analysis Reporting System, annual national CSV files 2000–2024 (accident, vehicle and person tables), public domain. Route pages are built for signed Interstate, US and state routes with at least 20 fatal crashes in 2015–2024. Data through 31 Dec 2024; generated 30 Sep 2026. See methodology and corrections.