/AI2h ago

Uber's ETA Model Uses L1 Regression, Biasing Wait Times Down

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Erik Bernhardsson@bernhardsson#701inAI

Sorry I'm stupid – I meant L1 regression! Not sure why this tweet blew up but I might delete and repost

Erik Bernhardsson@bernhardsson

I have had a weird theory for years that Uber fits their ETA model using Lasso instead of ordinary least squares. Which causes a bias towards shorter wait times.

6:45 AM · Jun 8, 2026 · 591 Views
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Erik Bernhardsson@bernhardsson

I have had a weird theory for years that Uber fits their ETA model using mean absolute error regression instead of ordinary least squares. Since wait-times have a long right tail, this will cause a bias that underestimates mean wait times (median < mean).

John Loeber 🎢@johnloeber

Standard experience booking an Uber

“5 minutes away”

I order it

“Finding your driver…”

“Pickup in 7 minutes”

I open my timer

9 minutes and 21 seconds later, it arrives

This is so tedious and I am tired of being deceived at the margin

1hViews 4.8KLikes 18Bookmarks 2
Erik Bernhardsson@bernhardsson

I have had a weird theory for years that Uber fits their ETA model using L1 regression instead of ordinary least squares. Since wait-times have a long right tail, L1 reg will cause a bias that underestimates mean wait times.

John Loeber 🎢@johnloeber

Standard experience booking an Uber

“5 minutes away”

I order it

“Finding your driver…”

“Pickup in 7 minutes”

I open my timer

9 minutes and 21 seconds later, it arrives

This is so tedious and I am tired of being deceived at the margin

1hViews 458Likes 8Bookmarks 2
@valerii_arch@valeriibo

@bernhardsson loss functions quietly become product behavior in cases like this

1hViews 22
sebastian@sebastianmxnt

@bernhardsson no!! where is the original post!?

1hViews 17
Botir Khaltaev@botirkhaltaevv

@bernhardsson For me it says 2 minutes away when the driver is literally right in front of me

1h