To demonstrate causality you need to:
- State what outcomes 172 is trying to achieve
- Determine that it is achieving those outcomes
- Assess the affect of achieving those outcomes
So, let's say that 172 is trying to reduce speeds (I have no idea if that is its purpose because it makes nearly everything illegal so its hard to tell). Are speeds reduced after the implementation of 172? I have no idea. I have no access to empirical evidence that illustrates this. Do you? Let's assume that it is reducing speeds. Is that improving safety? You would need to demonstrate that accidents were caused by speeding (they aren't) and that the affect of reducing speeding reduced accidents (it didn't). But go ahead, show some objective analysis.
I could easily spout that the reduction in traffic fatalities and injuries (should there have been any because that hasn't been illustrated by any studies I've seen) is only related to the improvement in airbags, improved structural integrity of vehicles, removal of older vehicles from roadways, improvements in seatbelt technology, improved response capabilities of first responders resulting in mediation of victim injuries, removal of light standards from close vicinity to roadways, improved weather, worsened weather, price of gas, gravitational affect of the moon, etc. All are equally justified claims without establishing a causal relationship.
Police services have excelled at subjective use of statistics to improve support for their initiatives for many years. "Crime rates are going up, we need more money to combat crime." Or, "crime rates are going down, we need more money to support our programs because they work." Ring a bell? Isn't that what you've been doing claiming in one thread that HTA 172 is making the roads safer while claiming in another thread that motorcycle accidents are up?