The arrival of driverless cars could be delayed by a bicycle shaped road-block.
Renault-Nissan has announced the launch of 10 self-driving cars over the next four 4 years, as automakers and tech firms race for pole position in the technology.
Renault's chief executive, Carlos Ghosn, announced the plans Thursday, saying the first semi-autonomous vehicles will debut this year, with a fully autonomous car ready by 2020.
However Ghosn admitted to CNBC that there was a major issue.
"One of the biggest problems is people with bicycles," he said.
"The car is confused by them because from time-to-time they behave like pedestrians and from time-to-time they behave like cars."
Ghosn also took a swipe at cyclists for failing to follow traffic laws.
"They don't respect any rules usually," Mr Ghosn said.
U.K.-based cycle advocacy group Sustrans told CNBC it was important that car makers realize roads aren't just for cars.
"Advocates of driverless cars often forget that people live next to roads and use them regularly, so safety must be prioritized especially when normal unpredictable and legal human behavior comes into contact with driverless machines," said Jason Torrance, policy director at Sustrans.
But cyclists are not the only issue facing developers of driverless cars.
In November last year an executive at Volkswagen highlighted the difficulties that an test on roads from San Francisco to Las Vegas had thrown up.
He warned that tumbleweed, police officers giving traffic directions and wild animals could all confuse driverless cars.
VW also says sensors on driverless cars still have problems in bad weather.
Despite the setbacks, big-name companies such as Apple, Google and Tesla are pushing forward with software for autos.
They've now been joined by Blackberry, who revealed technology allowing cars to 'talk' to each other and analyse real-time traffic scenarios.
But some carmakers are keen that Tech companies don't become the main driver of the auto sector.
In August BMW, Daimler and Volkswagen's Audi division jointly bought a Nokia mapping service to avoid having to depend on Google Maps.