According to most recent Department for Transport figures (2018), the UK has an average of five fatalities and 68 serious injuries every day on the roads. These numbers have remained relatively constant since 2011.
In addition to the loss of life, serious injury, and immeasurable distress these casualty statistics also have a direct economic impact on society. The total cost to the British economy is estimated to be in the region of £36 billion a year. This figure includes the knock-on effect of seriously injured road victims losing their ability to function and provide support for their family; ability to contribute to society, or to maintain a role in their professional role similar to that before the collision without care or assistance.
The table shows the average value of prevention by casualty/collision type in British £ (2018 prices).
Average value of prevention of per reported casualty per reported road collision, GB 2018
For every fatality on our roads there are 14 seriously injured casualties.
Although 'officially' speeding or inappropriate speed 'only' contribute to about 30% of all crashes, no one can dispute the fact that it is the impact on the human body from a vehicle driving above a certain speed that causes the death and destruction. 30-35MPH is measured to be the maximum speed where survival rates stay below 50%. Any faster than that and the chances of death grows exponentially.
From a physics point-of-view, the reason people are killed or maimed in collisions with moving vehicles is simple: the transfer of kinetic energy from a moving mass to the human body exceeds the limit for what our biotic structure can tolerate (absorb) before it is ripped apart. The impact causes us to die or sustain life-long injury. Being hit by a vehicle at any speed is enough to render us less able to live a normal life as a consequence. So, even if collisions are reported to be caused by driver error, lack of attention, weather conditions, vehicle failure, or whatever - it is the impact, caused by the vehicle's speed, on the human body that kills and injures.
Even WHO calculations put a human's probability of surviving an unprotected collision with a moving vehicle to 90% at 30mph, reduced to only 10% at 40mph. Yet, the public debate is still confused about what causes road users to die in road traffic collisions. There can be many reasons for drivers not being able to slow their vehicle down sufficiently within the available stopping distance prior to a crash but these reasons are not causing the destruction.
Lowering the average speed must, from the most logical point-of-view, be the best solution to bringing down the number of killed and seriously injured road users. It saves lives; it saves money.