How do you kill driveway grass?

If you are talking about the tall yellowish green grass that grows faster than your lawn, this is called Nutsedge. Even though it's identified as a grassy weed - it's actually not a grass or a weed, its a sedge so they had to invent a special herbicide just for that plant and its not cheap. Basagram, Manage, SedgeHammer and Dismiss are the brand name products that have been used through the years although some have been discontinued.

People call it water grass because heavy rains will bring it out. In Asia it appears in rice and peanut fields and the nutlets used to get inside peanut butter years ago hence another of its nicknames, peanut weeds.

Actually whenever the ground is disturbed you might find it. Around a new mailbox post, or a deck or after heavy rains or even an extremely hot summer.

The herbicide should be mixed in water - very little is needed as its highly concentrated. Its a hot product so gingerly spray the sedge sideways to hit the blades and not burn your grass. It shouldn't burn your grass as it is a selective herbicide but it is chemically hot and might burn. It is a summer problem and if you get it, you might have it for a few years.