A test track being built by the Insurance Institute for Highway Safety to measure the effectiveness of accident-avoidance technology is a welcome development.

The auto industry has made great strides in mitigating the effects of collisions. And plenty of researchers, including those at the IIHS, test how well seat belts, airbags and crush zones protect passengers in a crash.

But preventing collisions from happening is the emerging frontier in automotive safety. Automakers and suppliers are feverishly developing and marketing proprietary lane-departure and automatic braking and steering systems that are supposed to prevent accidents.

Do those systems work? Which work best? Until the IIHS finishes its $30 million test track in rural Virginia this fall, no independent third party is prepared to make a call.

It’s one thing to crash test cars into concrete barriers and calculate deceleration forces. It’s far more difficult to measure the effectiveness of a safety device when a collision did not happen.

But suppliers, automakers and ultimately motorists all need to know so they can decide which systems to use. The sooner the IIHS test track opens, the better for everybody.