We've just seen another attack where a vehicle was used as a weapon. My thoughts are with all those affected by the tragedy.
Many people are wondering how such attacks can be stopped. It's hard for intelligence to detect: a lone terrorist, no communications, no need to acquire weapons or suspicious chemicals. Sensitive facilities, such as airports and transport hubs already have bollards to prevent such attacks. But this doesn't help when ad-hoc crowds form, such as Bastille Day.
Could technical controls in vehicles prevent such attacks? A vaguely similar approach is used in high-quality colour printers to stop counterfeiting. Indeed, many cars have a number of sensors that can detect collisions, and some already take automatic action to avoid collisions.
It's not clear if these would stop a terrorist: perhaps they would stop a drunk driver mowing down a crowd, but a terrorist will try to disable the safety feature. And there are new safety risks if we prevent drivers overriding such systems: they may prevent a driver taking desperate action to avoid a tragedy.
To keep this question in line with Stack Exchange rules: answers must be evidence based, and focus on the question: Can technical controls prevent vehicle ramming attacks? This is not the place for open-ended discussion of vehicle safety or terrorism.