The National Highway Traffic Safety Administration is done being patient with robotaxis that treat emergency scenes like a traffic jam. On Wednesday, NHTSA Administrator Jonathan Morrison sent a pointed letter to autonomous vehicle companies, warning that driverless cars have been causing real problems for first responders — and that the agency expects fixes by the end of the month.

Morrison said the agency had identified a “clear pattern of driverless AVs interfering with law enforcement and other first responders.” The complaints aren't minor: robotaxis have reportedly entered live incident areas, blocked ambulances and fire trucks, and generally made life harder for the people trying to save lives. “An AV that cannot safely interact with first responders is a danger to the general public,” Morrison wrote, adding that NHTSA expects companies to “prioritize first responder interactions.”

The letter didn't name any specific company, but the message was clear: everyone needs to step up. NHTSA plans to schedule “meetings with driverless automated driving system developers by month’s end” to hash out solutions.

This isn't happening in a vacuum. Alphabet Inc. (GOOGL) (GOOG) recently had to recall nearly 3,900 Waymo robotaxis after reports of the vehicles driving into flooded areas and construction zones. Waymo also ended its partnership with Uber Technologies Inc. (UBER) in Phoenix, though the two still compete in other markets.

Meanwhile, Amazon.com Inc. (AMZN)-backed Zoox just unveiled an updated robotaxi and says it can crank out 100 of the pod-like vehicles at its California facility. Zoox has completed over 500,000 rides since launching in Las Vegas.

Tesla Inc. (TSLA) is also in the hot seat. CEO Elon Musk and AI lead Ashok Elluswamy have pushed back against claims that Tesla's autonomous tech was involved in a fatal crash in Texas, but NHTSA and the NTSB have both launched investigations. The agency is already probing over 3.2 million vehicles over Full Self-Driving (FSD) technology, and that probe recently moved to Engineering Analysis — a stage that usually precedes a recall.

For now, the clock is ticking. AV companies have until the end of July to show they can play nice with first responders. If not, NHTSA may have more than just a strongly worded letter to send.