Editor's note: Every week a Lake Oswego police officer answers your questions in this space. Please send your questions to reporter Cliff Newell at [email protected] or 503-636-1281, ext. 105.


"Why is the speed limit in a school zone 20 miles per hour and are there any recent changes to the school zones?"


In 1997, the traffic engineers at the National Highway Traffic Safety Administration (NHTSA), released a study that reported on the effects of vehicle speed on pedestrian fatalities and cited several studies that show that the risk of a fatality increases exponentially with the vehicle’s speed. 

The study concluded that at 20 mph a pedestrian has a 95 percent chance of surviving being struck by a car. At 30 mph, an increase of only 10 mph, that chance of survival drops to only 55 percent. At 40 mph your chances of surviving being hit by a car on foot drops to 15 percent. 

In the case of school zones, engineers decided a designated 20 mph school zone would best balance the needs of the motorist against the safety of children on foot and on bicycles. 

Throughout the city, flashing lights have been installed at school zones in high traffic areas to better alert and remind drivers of the school zone ahead and its designated speed. End school zone signs have been installed in most school zones, with the goal being to install signs in all school zones, that way motorists have clear understanding of when the school zone ends. 

If you travel through a school zone without an end school zone sign designator, the school zone ends when you pass the next posted speed zone sign. 

The police department actively and aggressively patrols the school zones throughout the city and receives almost daily complaints about drivers speeding through the school zones. It is critical that we all observe the 20 mph school speed zone when the lights are flashing. 

No driver wants to live with the thought of hitting a child in a school zone due to speeding, so please slow down. 

Lt. Doug Treat, Lake Oswego Police Department

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