In this context one should ask whether it is correct to strive for equal risk or
for highest benefit-cost returns on safety improvements. Striving for equal
risks on various parts of the road network or equal risks to various groups of
road users sounds politically correct, but is, in all likelihood, impossible to
achieve at reasonable economic costs. Urban roads will have fewer
fatalities per kilometre travelled than rural roads, because of the lower
speeds of travel. Motorways will have fewer fatalities per vehicle kilometre
travelled than other types of rural roads, because of the level of segregation
between different modes of transport (no slow vehicles) and the segregation
of movements (no at-grade intersections). It would be more fruitful to try
and find ways in which each category of road and road user is made safer
by applying cost-effective countermeasures.