It's a scene that could have come straight from a Hollywood blockbuster. A car comes screeching around a corner at nighttime, flies past and disappears. Moments later two police cars, sirens wailing, lights flashing, follow in hot pursuit. They manage to block the escaping car (which has no doubt knocked over a fruit stand in a busy market en route), but the criminals get out and continue their escape on foot, through alleyways, and into an abandoned warehouse. Their breath rasping, they sink to their knees, only to be pinned by bright headlights from two jet-black motorbikes, as law enforcement officers shout "Freeze!"
How did they catch up so easily? And how did the criminals not manage to hear them?
Electric bikes could give police officers an added tactical advantage on the roads (Zero Motorcycles)
It might sound, and even look, like something from Batman, but these bikes could in fact be an element in tomorrow's crimefighting arsenal. The Los Angeles Police Department is the latest to start evaluating electric motorcycles for its officers - including one that looks conventional, but that can run near silently (shown in the video above), and a more extreme version that was originally developed for the US Special Forces, which the LAPD off-road division will use.
Electric bikes are sometimes regarded as being at the more sedate end of city transport, so it may be surprising to learn how useful they can be in much tougher environments. "There are quite a few attributes that make these bikes appealing to the police and military," says Abe Askenazi, chief technology officer for Zero Motorcycles Inc, in northern California. "They're quiet; they're very stealthy," he says. That means they can be used to sneak up on targets, or even to follow people into buildings. Being electric, they don't have a noisy internal combustion engine, nor smoke-belching exhausts, which can give away their position. For the military and law enforcement agencies, these could be very useful features.
"There are major benefits to incorporating these environmentally friendly motorcycles," said Officer Steve Carbajal, from the LAPD Off-Road Unit in a recent statement. "Most importantly, our officers have an added tactical advantage while on patrol."
The Zero MMX Motorcycle has been assembled to military standards (Zero Motorcycles)
It's not hard to see what advantages a quiet-running bike could have when you're trying not to attract unwanted attention. When it comes to military special forces, being hard to hear could mean the difference between a successful surprise raid or battlefield rescue, and one where the enemy is alerted - and ready to react.
The Zero MMX Motorcycle looks like a lightweight motocross bike, built for racing, but is clad in stealthy matte black angular bodywork. It was assembled to military standards. "They had a laundry list of requirements," says Askenazi.
It has a modular power system with two separate batteries; the driver can use only one if they want the vehicle to be lighter. Both batteries can be replaced with a full battery in seconds. "The beauty of that for the military is that you get immediate charging," says Askenazi. The electric motor drive was developed in-house. There is no gearbox or chain, just a belt drive. It makes the bikes very simple to maintain and operate.
Electric bikes could be preferable to conventional models as they don't make a racket (Zero Motorcycles)
The list included extra functions, such as 'override switch' where a rider in trouble - being shot at for example - can hit the toggle to override all the safety systems for extra speed, even if that risks damage an overheated motor or battery. The military also wanted infrared lights (for night vision), and a reserve switch, like a reserve tank in a conventional, gasoline-powered bike. The battery was partitioned so that the rider has to flick a switch to use the final 20%, to consciously drive home the point that they are low on power. In a high-pressure situation, that might work a lot better than a blinking yellow light.
The proposed police bike is more than just intimidatingly quiet, however. In busy pedestrian streets, parks or promenade, these bikes could be preferable to a conventional motorcycle because "they don't make a racket, they don't disturb people," Askenazi says.
Electric police motorbikes are already being trialled in the Colombian capital Bogota; one hundred were deployed after the city's mayor issued an order for more sustainable transport. According to Askenazi, in the districts where the bikes are used, crime is measurably falling.
Crime fell in Bopgota, Columbia when electric bikes were tested on the streets (Getty Images)
Beyond military and law enforcement applications, Askenazi believes electric motorbikes could see much wider uptake, including for recreational riders. That certainly seems possible, with even the legendary Harley Davidson getting in on the electric action with its Livewire concept. At the moment electric bike technology is being driven by smaller companies, such as Brammo in Oregon in the US, or Energica in Italy, building an all electric superbike. But mainstream manufacturers are likely to come onboard as increasing interest is shown from the biking community.
Askenazi, a hardcore biker himself, believes the whole point of motorcyles is the feeling of independence and individuality, and the quieter electric vehicles could open up a new dimension for recreational riders as well. "A lot of people have said that it's more akin to flying than riding a motorcycle," he says. "It's just a neat experience, and so liberating."
If you would like to comment on this, or anything else you have seen on Future, head over to our Facebook or Google+ page, or message us on Twitter.