As my name signifies I love language. However I have just read this paragraph in tomorrow's Independent newspaper;

"While there was no blueprint for road safety, there were some basic, "low hanging fruit" measures including, tough laws against speeding, enforcement of drink-driving legislation, compulsory use of seatbelts and use of car seats for small children".

So there you have the context, but what the hell are low hanging fruit measures? And what is the root of the phrase?
Can someone please elucidate?