NYC Traffic Evolution
Nexar telematics data shows a +79.7% rise in IMU-detected collision rate year over year, coexisting with an all-time record low in NYC traffic fatalities. This study traces the structural causes (Congestion Pricing, fleet composition, a Feb 2026 penalty law) and finds the gap closing in April.
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More collisions, fewer deaths. Both true.
The +79.7% collision-rate increase is statistically ironclad, but it does not mean NYC roads are broadly more dangerous. Nexar's IMU-detected events and NYC DOT fatality data measure fundamentally different things: low-speed fender benders vs fatal high-speed crashes. NYC fatalities hit an all-time low (205 deaths, −19% vs 2024) in the same window where Nexar's collision rate nearly doubled. Both are correct. Section 07 reconciles them.
This study compares Nexar telematics for New York City across two identical four-month windows: Jan 1 - Apr 30, 2025 and Jan 1 - Apr 30, 2026. The headline is a +79.7% increase in the collision rate per million rides, from 234.4 to 421.2, statistically unambiguous (Z = 13.77, p < 0.0001) and largely explainable by the structural disruption of NYC's Congestion Pricing Zone, which went live in January 2025.
The collision-rate increase is real, statistically ironclad, and explainable, but it does not mean NYC roads are more dangerous overall. Rising Nexar IMU collision events coexist with all-time record-low NYC traffic fatalities in 2025. Congestion pricing is the unifying structural driver across nearly all findings.
Nexar's IMU detects vehicle impacts above a G-force threshold, including fender-benders that typically go unreported to NYPD. NYC DOT counts traffic fatalities. Congestion pricing produces more low-speed impacts (compressed traffic, high intersection density) while simultaneously producing fewer fatal high-speed crashes. Both datasets can be, and are, correct.
The divergence is the story.
Seven metrics, two periods, one analytical question. The collision rate moves sharply. Hard brakes stay flat. Harsh acceleration drops.
| Metric | Jan-Apr 2025 | Jan-Apr 2026 | Change | Severity |
|---|---|---|---|---|
| Total Rides | 3,750,716 | 3,271,738 | −12.8% | Fleet shift |
| Total Collisions · raw | 879 | 1,378 | +56.8% | Elevated |
| Collision Rate · per M rides ★ | 234.4 | 421.2 | +79.7% | Critical |
| Hard Brakes · per M rides | 29,855 | 29,848 | ~0% | Stable |
| Harsh Acceleration · per M rides | 1,556 | 1,168 | −24.9% | Improving |
| Avg Trip Distance · meters | 23,897 | 23,553 | −1.4% | Stable |
| Avg Trip Duration · seconds | 4,556 | 4,637 | +1.8% | Marginal |
A severe winter peak, then convergence.
The aggregate +79.7% masks an arc: a severe winter peak then sustained deceleration through spring, culminating in April 2026 reaching parity with April 2025. Bars show the 2026 monthly collision rate per million rides.
| Month | 2025 Rides | 2025 /M | 2026 Rides | 2026 /M | YoY Change | Signal |
|---|---|---|---|---|---|---|
| January | 888,325 | 116.0 | 819,314 | 297.8 | +156.7% | High |
| February | 855,024 | 176.6 | 623,427 | 567.8 | +221.5% | Peak |
| March | 967,661 | 282.1 | 876,603 | 516.8 | +83.2% | Elevated |
| April ★ | 979,327 | 359.4 | 915,503 | 356.1 | −0.9% | Converged |
April 2026 (356.1/M) is statistically indistinguishable from April 2025 (359.4/M), the first month with no measurable year-over-year deterioration. This may signal the start of a trend reversal as drivers, dispatchers, and city infrastructure adapt to post-CRZ conditions. May 2026 data will be critical for confirmation.
Elevated across every window.
Collision-rate increases are present across all time windows, school hours, off-peak weekday, and weekends, indicating a broad structural shift rather than a time-specific driver. Weekends show the smallest relative increase (+45.8%), consistent with CRZ selectively reducing leisure trips.
| Time Window | 2025 Rides | 2025 /M | 2026 Rides | 2026 /M | YoY Change |
|---|---|---|---|---|---|
| School Hours · 7am-6pm Weekday | 1,250,651 | 276.7 | 923,357 | 437.5 | +58.1% |
| Off-Peak Weekday · outside school hrs | 1,916,805 | 254.6 | 1,427,265 | 405.0 | +59.1% |
| Weekend · Sat + Sun, all hours | 1,188,490 | 306.3 | 884,225 | 446.7 | +45.8% |
Saturday stays the most dangerous.
All seven days show elevated 2026 collision rates. Saturday remains the most dangerous in absolute terms (461.8/M). Wednesday and Saturday show the smallest relative increases; Tuesday and Friday the largest. Bars show 2026 collision rate per million rides.
| Day | 2025 /M | 2026 /M | YoY | Severity |
|---|---|---|---|---|
| Sunday | 274.8 | 430.1 | +56.5% | High |
| Monday | 247.2 | 376.5 | +52.3% | Elevated |
| Tuesday | 255.0 | 443.2 | +73.8% | High |
| Wednesday | 288.5 | 403.2 | +39.8% | Moderate |
| Thursday | 266.7 | 428.2 | +60.5% | High |
| Friday | 258.8 | 435.1 | +68.1% | High |
| Saturday | 335.4 | 461.8 | +37.7% | Highest |
Wednesday (+39.8%) and Saturday (+37.7%) are the two days with the smallest YoY increases. Wednesday's mid-week stability may reflect more experienced commuter patterns. Saturday's lower relative increase despite the highest absolute rate is consistent with congestion pricing's selective suppression of leisure trips, the Saturday fleet in 2026 skews toward professional operators who handle risk better.
The single most important variable.
Of every external variable considered, the Central Business District Tolling Program (CBDT), NYC's Congestion Pricing Zone launched January 2025, is the single most important. It explains the ride-volume decline, the fleet-composition change, the collision-rate increase, and partially the weekend suppression effect: compressed traffic and higher intersection density mean more low-speed collisions in tighter quarters, even as fatal high-speed crashes fall.
Ride volume decline (−12.8%): some operators left the Nexar-equipped fleet as short CRZ trips became uneconomic. Fleet composition change: short FHV trips into CRZ down 9-35%; the remaining fleet skews toward longer, professional operators. Collision rate rise (+79.7%): compressed traffic, higher intersection density, more low-speed collisions. Weekend suppression: CRZ selectively reduces discretionary trips, sparing professional operators who drive carefully. Fatality decline (−40% in CRZ): the same compression removes the high-speed environment for fatal crashes.
Two datasets, one truth.
NYC recorded 205 traffic deaths in 2025, an all-time record low, −19% vs 2024. Q1 2026 showed 42 deaths, −7% YoY. This directly contradicts any reading of "NYC roads became more dangerous." Both Nexar and DOT are correct. Nexar's IMU detects vehicle impacts above a G-force threshold, including minor fender-benders in congested traffic that are never reported to NYPD. DOT counts fatalities and NYPD-reported injury accidents. Congestion pricing produces more low-speed impacts and fewer fatal high-speed crashes.
| Aspect | Nexar IMU · low-speed events | NYC DOT · fatal & reportable |
|---|---|---|
| Headline | +79.7% collision rate increase | −19% traffic deaths, all-time low |
| Detection / source | G-force threshold (onboard) | NYPD reports |
| Severity covered | Fender benders, moderate | Fatalities + injuries |
| Reporting | Always captured | Threshold-gated |
| Speed regime | Low-speed dominant | High-speed dominant |
| CRZ effect | Amplifies (compression) | Suppresses (less high-speed) |
NYC Traffic Deaths · 2025
The lowest annual figure on record, and −19% vs 2024. Q1 2026 continued the trend at 42 deaths (−7% YoY). The "more collisions" headline and the "fewer deaths" headline both reflect reality. Reading either without the other is wrong.
Credible partial drivers, none rivals CRZ.
Three additional external variables shape the dataset. Each is a credible partial driver, none rivals CRZ in explanatory power.
CRZ ≫ Penalty Law > Weather > FHV Market > School Cameras. CRZ explains a majority of the structural increase. The penalty law explains the behavioral metric (harsh acceleration). Weather is a candidate for the February spike specifically. FHV-market growth and school cameras were constants in the window, they shape context, not the differential.
The signal is not noise.
The +79.7% collision-rate change is the strongest single statistical result in any recent Nexar study. The 95% confidence intervals are completely non-overlapping, there is no plausible scenario under random sampling where the two rates are equal. The Z-score of 13.77 is far beyond the conventional 2.58 threshold for 99% confidence.
The 95% intervals are completely non-overlapping. The change is real. The analytical question is therefore not "did the rate change?" but "why did it change?", and the answer is primarily structural (CRZ, fleet composition), not behavioral deterioration.
Methodology
Data source. All metrics are derived from IT_TRX_RIDE_LOCATIONS_CLASSIFIER, Nexar's internal telematics table partitioned by ride_start_date. The table contains ride-level records including trip metrics and collision-event flags for Nexar-equipped vehicles. NYC rides were identified using state = 'New York' with city-name variants covering the five boroughs, including English and Cyrillic encodings (4 multilingual variants).
Time windows: School hours = Mon-Fri 7am-6pm; Off-peak weekday = Mon-Fri outside that; Weekend = Sat + Sun all hours; timezone America/New_York (ET). Statistical test: two-proportion Z-test, 2025 vs 2026 rates, Z = (p₁ − p₂) / SE with SE from pooled proportions, 95% CIs from period-individual SE. Result: Z = 13.77, p < 0.0001.
Collision Rate = (total collision events ÷ total rides) × 1,000,000. Collision events are IMU-detected impacts above a calibrated G-force threshold, not NYPD-reportable accidents. Mapping to police-reported collision counts requires a separate calibration step outside the scope of this study.
This analysis corrects issue #48, which incorrectly compared January-April 2024 vs January-April 2025. The current analysis uses the correct comparison window: January-April 2025 (baseline) vs January-April 2026 (study period). All findings supersede prior publication.
Five actions, ranked by priority.
Monitor May-June (highest priority)
Confirm or refute the April convergence. If May 2026 continues at ~April 2026 levels (~356/M), a trend reversal is confirmed and the elevated Jan-Mar 2026 window can be classified as a transient disruption phase rather than a new baseline. The single most actionable next step.
Investigate fleet composition
The −12.8% ride decline is unexplained by TLC market data (which grew +2.6% YoY). Identify which operators left the Nexar network between 2025 and 2026. If the departing fleet was systematically different, the per-ride collision-rate change is partially a selection artifact.
School-zone spatial deep-dive
+58.1% with no external corroboration. A spatial analysis cross-referencing Nexar ride segments against NYC DOT school-zone boundaries would determine whether school-proximate roads drive the school-hours elevation, or whether it is a general time-of-day effect surfacing during the school window.
Weather attribution · February
February 2026 peaked at 567.8/M (+221.5%). Adding NOAA snowfall/precipitation data for Feb 2026 vs Feb 2025 would separate weather contribution from policy-change contribution. If snowier, weather explains; if not, the penalty-law adjustment period was the driver.
CRZ zone segmentation
Split the analysis into rides that enter the Manhattan CRZ vs rides that remain outside it. This would isolate the congestion-pricing effect precisely and provide a cleanly attributable metric to share with NYC DOT as evidence of CRZ behavioral impact.
Limitations & caveats.
Limitations are presented as a first-class section, not a footnote. These define the scope within which the +79.7% headline should be interpreted.
L1 · Collision definition mismatch
Nexar IMU-detected events ≠ NYPD-reportable accidents ≠ traffic fatalities. These are not directly comparable to any city-wide safety statistics. Nexar collisions include minor impacts invisible to NYPD reporting thresholds.
L2 · May 2026 excluded
No May 2026 data was available at time of analysis. The comparison uses four complete months only. May 2026 data would be the critical test of whether the April convergence holds (see Recommendation R1).
L3 · Fleet composition confound
The −12.8% ride-volume decline may reflect fleet turnover, not demand. If the surviving 2026 fleet is systematically different from the 2025 fleet, per-ride metrics may be biased. This cannot be resolved without operator-level data (see R2).
L4 · Monthly count gap (~60,000 rides)
A ~60K-ride gap exists between the aggregate total (3,750,716 in 2025) and the sum of monthly counts (3,690,337), due to a Cyrillic city-name variant present in the full-period query but excluded from the monthly breakdown. Rates within each query are self-consistent; the gap does not affect findings.
L5 · Geography encoding
The NYC filter uses 4 multilingual city-name variants. A small fringe of rides with non-standard or missing city encoding may be excluded from both periods consistently, making this a stable bias rather than a differential one.
Appendix · data sources.
Primary · Nexar internal
| Field | Specification |
|---|---|
| Source table | IT_TRX_RIDE_LOCATIONS_CLASSIFIER |
| Partition | ride_start_date |
| Rows analyzed | 4.4M+ rides |
| Geography | New York City · 5 boroughs · 4 city-name variants |
| Periods | Jan 1 - Apr 30, 2025 & Jan 1 - Apr 30, 2026 |
| Collision detection | IMU G-force threshold · onboard sensor |
| Timezone | America/New_York (ET) for time-window analysis |
External · public data referenced
| Source | Used for |
|---|---|
| MTA / NYC DOT · CRZ Year 1 Report | −11% entries · −7.1% VMT · −40% CRZ fatalities · short FHV trip declines |
| NYC DOT · Vision Zero | 205 traffic deaths in 2025 · −19% vs 2024 · Q1 2026 figure |
| NYC TLC · Open Data | FHV market growth +2.6% YoY · contradicts fleet-decline narrative |
| NYC DOT · Speed Camera Program | 2,200 cameras · 750 school zones · 24/7 since Nov 2022 |
| NYC Admin Code · Feb 2026 | License-suspension thresholds · speeding-point penalties |
Analysis conducted by Rui Carneiro · nexar-ai.com. Requested by Itamar Bul · Corrects prior analysis (issue #48) · Nexar BI Automated Analysis System. NYC Traffic Evolution · Generated May 25, 2026 · Data period Jan-Apr 2025 & 2026 · Geography New York City.