Why are the street lamps on Interstate 15 so tall?

Saturday, Aug. 29, 2009 | 2 a.m.

Transportation officials say they use towering, “high-mast” lights because they are more efficient — nine or 10 times more by one measure.

The higher the light, the greater the surface illuminated below. Raising it to 100 feet — 60 to 70 feet higher than the standard streetlight — and placing it in the freeway’s center divider instead of along each shoulder, allow one high-mast light to do the work of nine or 10 shorter light poles.

Officials note that fewer lights translates into lower maintenance costs. And in case you were wondering, the high-mast lights are lowered using a pulley system inside the pole and serviced at ground level.

There’s a “How many Department of Transportation workers does it take to change a light bulb” joke here, but Mr. Sun will restrain himself.

Questions for Mr. Sun can be sent to [email protected].