[BUG] 2026 China GP generated lap 1 for DNS drivers

[Casper-Guo]

Describe the issue:

The four DNS drivers in 2026 China GP has a lap 1 generated for them

Reproduce the code example:

import fastf1 as f
import pandas as pd

pd.set_option("display.max_columns", None)
session = f.get_session(2026, "China", "R")
session.load(telemetry=True)
laps = session.laps
print(laps.pick_drivers("ALB"))

State your Fastf1 version number:

3.8.1

Error message:

Time Driver DriverNumber LapTime  LapNumber  Stint  \
266 0 days 00:58:03.760000    ALB           23     NaT        1.0    1.0   

    PitOutTime PitInTime Sector1Time Sector2Time Sector3Time  \
266        NaT       NaT         NaT         NaT         NaT   

    Sector1SessionTime Sector2SessionTime Sector3SessionTime  SpeedI1  \
266                NaT                NaT                NaT      NaN   

     SpeedI2  SpeedFL  SpeedST IsPersonalBest Compound  TyreLife  FreshTyre  \
266      NaN      NaN      NaN          False     HARD       1.0       True   

         Team           LapStartTime            LapStartDate TrackStatus  \
266  Williams 0 days 00:56:24.050000 2026-03-15 07:03:59.831          12   

     Position  Deleted DeletedReason  FastF1Generated  IsAccurate  
266       NaN    False                           True       False

[Casper-Guo]

Something that is interesting:

The Pirelli graphic for the Chinese GP also shows a lap for the 4 DNS drivers even though none of them even attempted the formation lap:

Same behavior for Hulk in the last grand prix.

This is not how they used to do thing. See 2025 Austrian GP, where Sainz was classified DNS. He was not shown on the graphic:

Either they just decided to do their graphics differently, or they are pulling their data from us. The latter would be very annoying since we can no longer rely on them as an independent source

[Casper-Guo]

Same buggy behavior seen with Hulk in the Austrian GP.

Purely based on my own usage and without looking at the code, this bug may be contingent on the freshness of Jolpica information. I ran a script last week before results data were available and did not see this bug.

[theOehrly]

Yeah we really shouldn't generate a lap for those drivers, I agree.

And maybe I need to send an email to Pirelli 😅

[saivedant169]

The fake lap gets generated at line 1503 in core.py. When a driver has tyre data (they were assigned tyres on the grid) but no timing data (they never actually drove), the code creates a generated lap for them. The comment on line 1506 even says 'this potentially adds a nonexistent lap for drivers who could not start the race'.

Fixed by checking if the driver is DNS before generating. If their Position in results is NaN (set during _load_drivers_results for missing drivers), we skip them instead of creating a lap.

PR incoming.