Experts believe self-driving cars could soon be cruising the streets of Britain in 15 years, inevitably making them the next target for hackers and terrorists looking to cause chaos on the road.

A new report released by the Institution of Engineering and Technology (IET) says holes in the software used to power driverless cars will most likely exist for malicious individuals to exploit for their own purposes, such as steal cars, cause traffic to stall, or maneuver them remotely so that they crash into other vehicles, structures and pedestrians on the street.

"Sadly, we're not that good at writing software today," laments IET cyber security expert Hugh Boyles, as "98 percent of applications have serious defects."

Boyles notes that for every software found with a glitch, around 10 to 15 security holes on average are actually discovered. Boyles believes that the software used for most driverless cars could also be prone to the same problem.

"If we have the hacker community start to target vehicles in Central London, we could imagine a fair amount of chaos on the road," Boyles says. "Terrorism is a real risk. So cyber security of autonomous vehicles will be critical. And we're going to have to consider having black boxes in vehicles in the event of an incident."

Cars have become more and more autonomous in recent years, with features such as cruise control, parking assistance and distance monitoring being incorporated into the latest car systems. Right now, the average vehicle, which is still mostly non-autonomous, contains 60 microprocessors and runs on more than 10 million lines of software code. With fully automated vehicles, hackers will have more to work with to wreak havoc on the streets.

The IET report, however, acknowledges the benefits of driverless cars, and with 15 or so more years before the cars hit the road, automakers still have plenty of time to improve their game and build better software that will not be prone to hacking.

One major benefit experts predict will be less driving errors and better road safety for all drivers, minus the risk of hacking and terrorist attacks. For every 10,000 human errors made while driving, the IET believes driverless cars will only make one.

So far, Google's driverless cars, which has covered more than 1 million miles of ongoing testing, has only seen one accident, and it was during the time a human driver took over the wheel.

Congestion, too, will become a thing of the past, as these cars can be programmed to veer away from busy spots and travel in "platoons" that link to traffic light systems to get them moving, while staying closer to provide more road space. Driverless cars will also eliminate the problem of speeding as they will most likely be equipped with a speed limit.