I suppose there’s a perfectly good reason for the difference in terminology:
From an operational standpoint, speed humps and bumps have critically different impacts on vehicles. Within typical residential operational speed ranges, vehicles slow to about 20 mph (32 km/h) on streets with properly spaced speed humps. A speed bump, on the other hand, causes significant driver discomfort at typical residential operational speed ranges and generally results in vehicles slowing to 5 mph or less at each bump.
But seriously, does this difference—unknown to the non-traffic-engineering layman—overcome the possibility of roadside carnage when said layman drives off of SW Cabot St. in Beaverton in a paroxysm of juvenile laughter? Or accidents caused when they go unnoticed because the signs have been kifed by guys unintentionally adding a little versimilitude to their bach pads?
Paul Boehlke said about two or three months ago, some of the speed hump signs started disappearing one by one.
And while he doesn’t exactly know what happened to them, he does have a theory.
“Kids, you know i guess if i were a teenager, a speed hump sign might look pretty good in my bedroom, I don’t know.” said Boehlke.
When Barbara and I were in Ireland we saw huge signs for “RAMPS” in places where we didn’t see any potential for boating. I suppose if you called something a “SPEED RAMP” here it would just be a challenge for some Evel Knievel-style daredevil.