Do speed cameras make the roads safer ~or~ the city more money?

I really want to hear from law enforcement.

I’m looking into buying a radar detector and need to know what to look for so I don’t throw money away on a useless piece of equipment.
Ken – Thank you for the info. I won’t invest in a piece of equipment that will not prevent me from getting any speeding tickets.

I am looking to buying a radar detector for my boyfriend as a gift, but don’t want to spend very much ( or less). For the small amount I want to spend, which radar detector for my money? Brand and model is helpful!

I need a gps and laser detector. So trying to save money and find one that does both. After tedious searching I see the TomTom 720 gives you the most for your buck. So just cant find any info on if it has the built in laser detector or if i need to buy a separate one.
If it doesn’t have, does anyone know of a gps that does have a built in laser detector?