With municipal budgets now tighter than ever, towns all over the world have started turning off their street lighting at night to save money. Saving money and electricity is fine, but what about when Grandma's pooch needs to go walkies at 2 AM?

A few towns in Germany may have come up with a solution. They have modified their lighting grids using a system called Dial4Light, so that local residents can use their cellphones to selectively turn on the lights street by street. After 15 minutes, a timer plunges the street back into inky darkness. Towns implementing the system, have typically seen a 25 percent savings in their street lighting bills.

Of course, another solution would be to simply use more efficient lighting.

BBC News, via Treehugger.com