An emergency call system dubbed eCall will be installed in all new cars from March 2018 under an agreement reached at the European Parliament.
The system will send an automated call to the emergency services in the event of an accident.
Research suggests that the mandatory use of the system could halve response times, especially in rural areas.
But one expert questioned why it was going to take so long to be implemented.
The proposal was originally made in 2012 but was delayed for a variety of reasons, including privacy concerns.
Critics were unsure of the need for a government-mandated in-car system that would track a vehicle's location.
Under the new deal, the eCall system will give emergency services only basic data such as:
- type of vehicle
- fuel used
- time of accident
Antonio Avenoso, executive director of the European transport safety council welcomed the initiative.
"Getting emergency services to the scene of a crash quickly is crucial to preventing deaths. So, this technology will save lives," he said.
"However, it's regrettable that it will be several years before we see all new cars fitted with the system and that other vehicles aren't covered by the legislation yet.
"These are missed opportunities to extend the safety benefits further, with little or no justification."
The rules are now subject to formal votes in the European Parliament and by all member states, likely to take place in March next year.