SPEED CUSHIONS Note: These can also be used in conjunction with bulges as shown in this schematic.   A speed cushion is a variation on a standard speed hump. However, these devices do not span the entire width of the roadway but taper off at the edges. The width of the raised portion is sufficient to ensure that cars have to pass over some of the hump but may allow buses and emergency vehicles to pass over with less impact. The speed cushion dimensions are about 7' wide, 10' long and 3" tall. Most passenger vehicle axle widths are around 6', so they cannot straddle speed cushions as emergency vehicles do. Speed cushions are designed to slow traffic to 25 mph and lower traffic volume by 5 - 7%.   Temporary Installation Austin, TX Source: http://www.ci.austin.tx.us/roadworks Permanent Installation Note: Buses are impacted less than cars PROS 1. Potential to reduce traffic speed. 2. Reduces traffic volumes. 3. Can be used to reduce cut-through traffic. 4. Self-enforcing. 5. Minimal impact to on-street parking. 6. Minimum maintenance. 7. OK for emergency vehicles. CONS 1. Care needed if placed on transit routes. 2. May transfer problems elsewhere. 3. Not aesthetically pleasing. 4. May cause vehicles to encroach into bicycle lanes. Summary of Effectiveness Volume Reduction Yes (Locally) Speed Reduction Yes Safety Improvement Possible - - Streets to Use On Collector, Local Local Use on Bus Route Yes Use with Curbs and Gutters Yes Spot or Area-wide Use Spot - - Emergency Service Access Issues Minimal Impacts on Arterials Possible Change in % Trucks Unknown Environmental Changes Unknown - - Dependence on Enforcement No Level of Violation N/A - - Aesthetics and Landscaping No

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