A cloud-based database of highly-detailed maps updated in real time will be essential for self-driving cars, as they can provide information on traffic and road conditions far beyond a car's onboard sensors. Two of the leading firms developing such maps have now joined forces to help accelerate the arrival of self-driving cars.

Digital mapping firm HERE (owned by Audi, BMW and Mercedes-Benz) and vehicle sensor technology firm Mobileye on Thursday announced they’ll combine their data to form a common platform that self-driving cars can utilize. Specifically, Mobileye’s Roadbook database will become an important data layer of HERE’s HD Live Map.

Roadbook is a database updated in real time by vehicles fitted with Mobileye’s sensors and includes data on roadway markings such as lanes, road boundaries, barriers and similar items, as well as various traffic signs such as directional signs and traffic lights. Mobileye’s sensors are already used by 27 automotive brands and the list is growing.

HERE’s HD Live Map, using data like that from Roadbook, creates in real time a highly-detailed digital representation of the world, which self-driving cars can then tap into. The HD Live Map is composed of tiles and contains dynamic content layers. Each layer provides different details: lane level information, dynamic road network and situation changes, and speed profile data for vehicles on the road.

Detecting changes in the real world, such as a sign being knocked over or a tree branch on the road, and adjusting the map accordingly is critically important for self-driving cars to calculate their routes. With more sensor data available from car manufacturers equipped with Mobileye’s sensors, the HERE HD Live Map will be updated even more quickly.

Though fully self-driving cars are likely years away still, some of the more basic data from HERE’s HD Live Map will be made available to cars as early as 2017. For example, cars with access to the data will be able to receive real-time information for traffic jams, traffic signs, potential hazards and even parking spots.