There's a race going on in the world of autonomous transport to see which self-driving vehicle is the first to become a regular sight on the roads - the car or the truck. Right now, it looks as if the latter is winning, and a new startup consisting of former Google, Apple, and Tesla engineers wants to speed up the process by adding semi-autonomous features to existing commercial trucks.

The San Francisco-based company, called Otto, wants to make hardware that can be retrofit into existing trucks, rather than building the vehicles from scratch.

Because trucks tend to stick to highways when following their routes, giving them autonomous functions is easier than trying to do the same thing with cars, which have to navigate complicated city streets. Whenever the rigs leave the highways, drivers will be required to take over.

Otto's kit includes much of the same hardware found in autonomous vehicles, such as cameras, radar, and lidar sensors. The trucks will be able to stay within their lanes, maintain a certain speed, and slow down or speed up themselves.

Otto's kits obviously don't turn the vehicles into fully self-driving machines; humans will still need to be present. But the company said its product could, among other things, allow a driver to grab some sleep while their truck carries on down a highway - meaning the vehicles can safely operate for longer periods of time than their non-autonomous counterparts, providing regulators allow it.

The company promises that its product will be affordable. There's already been one public highway demonstration of the system in action and Otto plans to improve the trucks' capabilities before it "bring[s] the technology to every corner of the US highway."

Last month, six of Europe's largest truck manufacturers took part in the European Truck Platooning Challenge, which saw six convoys of semi-autonomous vehicles spend a week driving across Europe.