Speed Bumps & Speed Humps | Traffic Safety Store. With four types of mounting hardware to choose from; 12” galvanized steel spikes, 5” lag bolts and anchors, 3” Large Diameter ‘TapCons’ (LDT), or our exclusive Heavy Duty 18” galvanized steel spikes, free with each order of rubber speed bumps, nobody offers better service on reflective rubber speed bumps than the Traffic Safety Store.