The comparison I was making was with a road with the same number of live lanes with and without a hard shoulder. You may regard this as an unfair comparison bec

The comparison I was making was with a road with the same number of live lanes with and without a hard shoulder. You may regard this as an unfair comparison because the cost to fully add a new lane is so much higher. However, I'd postulate that any improvement in safety due to a reduction in congestion is bound to suffer from the Jevons paradox in the fullness of time.