A government agency wants all new cars made from 2021 to be able to talk to one another. The National Highway Traffic Safety Administration plan is designed to improve road safety.

After two years of consultation, the agency has now issued a notice of proposed rulemaking, the last step before introducing a new rule. The idea is for cars to carry what are known as dedicated short range communications radios and communicate using a common technical standard.

The radios would transmit up to 10 times a second, carrying data such as direction, location and speed. As well as communicating with vehicles, the cars would also communicate with radios on traffic lights and stop signs.

The idea isn’t to affect the operation of the car itself, though makers of vehicles with automated and assisted driving technologies could use the data. Instead the radios would process the data and alert drivers if they needed to take imminent action to avoid a crash.

According to the agency, the technology would make a particularly big difference in situations where drivers can’t necessarily see everything that could affect their driving decisions, such as when overtaking, turning left across traffic, or coming up to an intersection. It forecasts the technology could either help avoid a crash completely or minimize the damage in 80 percent of the crashes that don’t involve an impaired driver.

The agency says the technology concerned doesn’t involve any data that either identifies or could be linked to an individual. That issue is likely going to be a big privacy concern given that in theory the radios could help track a suspect’s movement or simply track when a driver exceeds the speed limit in a particular area.

If the rule gets the go-ahead, it’s most likely to start taking effect from 2019 on a proportion of new vehicles before becoming mandatory for all new vehicles in 2021.