American law follows the basic idea that most people are reasonable and laws exist to control the few who are unreasonable or inconsiderate. The posted speed zones follow the same idea. The methods for establishing speed zones are based upon careful studies that have been performed in Oregon and throughout the United States.
These studies show that traffic moving at a speed that is reasonable for the road and weather conditions results in fewer accidents. Drivers are more patient because a reasonably uniform speed allows progress with less passing, less delay, and fewer rear-end collisions.
Many people believe that lowering posted speeds will mean fewer accidents, but studies do not prove this. Unrealistically low speeds frustrate many drivers, resulting in numerous speeding violations and unsafe driving, actually causing more accidents. Some motorists may try to make up time by taking a shortcut through residential or other areas that are not suited to higher speeds and increased numbers of cars.
State statutes give Oregon motorists the following speed zone standards:
- 15 mph - Alleys, narrow residential roadways
- 20 mph - Business districts, school zones
- 25 mph - Residential districts, public parks, ocean shores
- 55 mph - Open and rural highways (all vehicles); trucks, school buses, worker transport buses on interstate highways
- 65 mph - Autos on interstate highways
Posted speeds override these statutory standards.