Driveway on neighbors property

[Chris Hart]

I'm looking to expand my driveway. It currently can fit about 3 cars single file which is a huge pain. I started getting quotes in the late fall with plans to start it in the spring. After doing some research it seems like I would want about 24'. I would be able to widen my driveway to about 20' to keep it completely on my property. The contractor suggested asking the neighbor if I could widen it a couple feet into his property. We would still have about 2-3' of grass between our driveways. I like the idea but I feel like this could lead to problems in the future. Has anyone done this before? What issues could I face doing this? 

Thanks for any info advice