Alejandro Vizio built CURB — a free, open-source web and iOS tool — after racking up roughly $2,000 in parking tickets with his girlfriend. Its most useful finding: San Francisco's street sweepers typically arrive about 22 minutes after the posted start time, based on two years of the city's own citation records.

On a block in Haight-Ashbury, the sign says the sweeper comes at 7 a.m. Two years of San Francisco parking records say it typically arrives around 7:22.

That gap — documented by a developer using the city's own open data — is the founding insight of CURB, a free web and iOS tool built by Alejandro Vizio, a front-end developer who lives in the neighborhood. SFGate reported this week that Vizio and his girlfriend accumulated roughly $2,000 in street-sweeping tickets before he decided to build his way out of the problem.

CURB (curb.guide) pulls from DataSF, the city's public data portal, to display every SF curb color-coded by when the next sweep restriction starts. The map layer is useful; the historical record underneath it is the point. Vizio analyzed two years of citation records to calculate when enforcement actually arrives — not when the posted sign says it will. The average lag across city blocks: 22 minutes. The site carries a disclaimer, in its own language, that "the posted sign is always the final word." It's also accurate. The app doesn't say it's safe to leave your car; it says what the data shows about how the rule tends to function.

The city's sweeping machine generates enough tickets to fund a small city department. SFMTA collected $65.1 million in street-sweeping citation revenue in 2025; since 2021, the agency has written more than 3 million sweep tickets citywide. The Mission leads all San Francisco neighborhoods in sweep violations, the Sunset runs second, and roughly a third of all appealed parking tickets in the city have been dismissed over the past three years, according to SF Standard.

CURB is not the first tool built in response to that enforcement volume. Pablo Felgueres and MaryLouise Howell, NoPa residents who racked up about $900 in tickets after buying their first car, built Street Cleaning Parking — an iOS reminder app at $14 a year — in December 2023. A 23-year-old data engineer named Riley Walz built Find My Parking Cops in September 2025, which surfaced enforcement-officer locations in near-real time; SFMTA shut it down within four hours, citing staff safety. CURB operates in a different lane: MIT-licensed, open-source, built entirely on public data, with no apparent friction from the city.

The app launched as a web tool and now includes an iOS version in the App Store. It has logged more than 2,500 visitors since its launch and collects no user data.

SF Public Works sweeps roughly 150,000 curb miles per year, pulling 25,000 tons of material off the streets. What Vizio built, at its core, is a way to read a city schedule as it actually runs, not as the sign says it does — which turns out to be a different thing.