Here's an interesting concept that a colleague alerted me to. It's a speed bump that stays flat if the motorist hits it at speeds of under 30km/hr.
Designers Jae-yun Kim & Jong-Su Lee have designed a speed bump that’s based on retractors that open if the impact with them is small enough. These speed bumps can be configured so that if a car is going below 30km/h, the speed bump flattens; over 30km/h, the force causes the retractor to stay closed, keeping the speed bump active. Great idea I reckon! Why punish people when driving at about 15km/h.