No one should be surprised by Tuesday's terrorist attack in New York City.

As we've seen in Jerusalem, Nice, Berlin, London, Stockholm, and Barcelona, it's exceptionally difficult to prevent terrorists from using vehicles to commit murder, and so we will have to think long and hard about means we can use to counter this threat.

The challenge here isn't just that vehicles are readily accessible and capable of causing immense physical carnage, it's that vehicle-based plots are very difficult to detect.

Consider the contrast with an explosives-based plot.

Before he or she can carry out a bomb attack, an individual must research how to build a viable device, acquire the components and material to construct that device, then detonate it effectively. Each of these steps is technically complicated and affords different opportunities for intelligence service detection.

Conversely, a vehicle attacker needs only a matter of minutes to acquire their vehicle and then use it to inflict mayhem. While the potential casualties of a major explosive detonation are higher than a vehicle attack, terrorists will take what they can get.

That preference for maximized flexibility is at the heart of Islamic State attack plotting and it has encouraged other groups such as al Qaeda to follow in the same vein.

Still, we do have untapped tactics with which to defeat vehicle attacks.

First off, security services can lay down barriers to obstruct vehicle attacks in areas where crowds gather. To its credit, the NYPD engaged in a wide-ranging vehicle obstruction effort during last year's Thanksgiving parade. As did London's Metropolitan Police during this summer's Wimbledon Tennis Championships. While it's impossible to use vehicle barriers at every site, where public events are prioritized for protection, those events can progress unhindered.

Another possibility would be to establish a waiting period for the rental of larger trucks such as those used in the Nice and Berlin attacks. Nevertheless, there is a limit to what can be done here. That’s because extending this approach to other smaller trucks would destroy businesses like U-Haul and Home Depot while causing too much inconvenience across society.

That speaks to something: There’s a limit to how much freedom we should sacrifice in confronting terrorism.

Third, those convicted of terrorism-related offenses should have their driving licenses suspended. While this wouldn't prevent every vehicle attack, it would create obstacles for those who have been released from prison but are believed to pose a threat.

Fourth, we need to see greater synergy of effort between government, imams, non-governmental organizations and educators in drawing attention to the reality of terrorist groups. Consider ISIS, for example. Where ISIS once claimed ordained victory over all the Earth, its fighters now run around in the desert getting bombed.

The key here is to puncture the terrorist narrative of purpose. If we do, we’ll see fewer individuals will be inspired to join their cause.

Ultimately, however, if we want to maintain our open and dynamic society, we’ll have to accept that attacks like Tuesday's will sometimes occur.