A wave of lawsuits against cities over the practice of marking car tires with chalk to catch violators of time-restricted parking zones has come to San Francisco, and one woman is suing the city for $50 million over the practice.

As the Chronicle reported over the weekend, the lawsuit filed in the name of Maria Infante is over a $95 parking ticket that was issued based on the chalking of tires. It's seeking class-action status, and it comes on the heels of a Sixth Circuit decision that ruled in favor of a Michigan woman — arguing that chalking tires may amount to a Fourth Amendment violation as an unreasonable search.

The lawsuit was filed by attorney Eduardo Roy, who also filed a similar lawsuit with a different plaintiff against the city of San Leandro.

Fourth Amendment expert Orin Kerr, a UC Berkeley law professor, tells the Chronicle that the question about whether this century-old practice of tire-chalking is constitutional "ends up being a surprisingly interesting Fourth Amendment question that nobody expected, with a quirky and totally pedestrian fact pattern."

So far, no judge has made a definitive conclusion about whether the chalk amounts to a "search," and the question is going to come up for the Ninth Circuit soon, after a trial court in San Diego recently ruled that chalking is not unconstitutional.

The San Francisco City Attorney's Office issued a statement about the case, saying that chalking tires is still done but it is "not the main tool" anymore when it comes to enforcement — many cities employ digital license plate scanners for this purpose. Spokesperson John Cote tells the Chronicle that parking control officers "have a tough job, and they do it lawfully and thoughtfully to help keep the City moving so people can get where they need to go."

Whether or not they succeed, these lawsuits may mean that the practice of chalking tires will end in the cities that still do it, like San Francisco and San Jose — Oakland and Berkeley have moved on to other methods.

Photo via SFMTA