- Freehand painting - I had an old striper tell me that he could paint straight lines without any guides. He said"Just aim the machine like you would aim a gun" He made a mark at the beginning and end of the line, pointed the striper, and took off. It did save a lot of time for him, but the results were not good enough for me. I could drive by a lot and a quick glance told me that it was one he painted. None of the lines were perfectly straight, and there were always a few "banana lines" where he rolled over a pebble, or just made a mistake in his lineup. Maybe those lines were good enough for him and his customers, but I couldn't sleep if mine looked like that.
- String lines - I know a striper that uses nails or weights to hold a tight string. He works alone, driving concrete nails in asphalt and tying string lines to the nails to make his layout. When he gets through, there is string all over the parking lot. He says it's faster than chalklines, but I tried it on a few jobs, and it's not. Also, since he paints his line next to the string, you can see the mark left by the string in the overspray from his striper.
- String and spray paint - This is how the long line guys do it on highways. Pull a string out tight and spray dots of paint with an upside down spray can. Then paint to the "shadow" left by the string. This is a good way to do it, you get a straight line to follow, but on short lines, it takes a lot more time than a snap. Also the dots of paint left behind are unsightly because they remain on the pavement a long time. You could use spray chalk instead of paint, but the chalk might keep the striping paint from sticking.
- Two helpers and a rope. Not a bad way to do it - make your layout marks at the beginning and end of each stripe and have two helpers pull the string tight over the marks. This can be a good way to do it when you are doing a big parking lot with multiple rows of parking that line up with each other. Pull it tight and paint all the way from one side to the other. But it takes longer than snapping chalklines on single or double rows. Also on windy days the string can move around and make you paint crooked lines.
- Graco AutoLayout - I have an AutoLayout and love it. The instructions show that you can use the machine to make layout marks at the beginning, middle, and end of the painted line, then aim so that you paint a straight line. The AutoLayout lets you do this quickly, and it measures and marks quite accurately, but every now and then a rough spot or loose pebble will cause the machine to get off track and you won't know until it's too late.
So - you really should snap a chalkline for every line you paint. That's a real pain in the butt, isn't it? Well, maybe you are just making it out to be harder than it really is. With a little practice, it gets faster and easier. Look at my other posts about the right way to snap a line on pavement. Or check out this video. You don't snap it like a carpenter, pulling up in the middle and letting go, that only works on flat boards and short distances. Snap it like a striper - hold it tight on one end, and whip the other end with a flick of the wrist. With practice you can snap quickly, straight, and mark over high spots and low spots, not like the carpenter method that only hits the high spots.
And then when you get the lines snapped, step back and look at the layout. This gives you a chance to see if you have made any mistakes in the layout. The chalklines show where the paint is going and lets you see if you made a mark in the wrong place, or got somethng out of square. It's a lot easier to fix if you spot it before you paint.
I have been doing this for 25 years, and I am a lazy guy. I don't like to do more than it takes to get the job done. I'm also a busy guy and like to get done as quickly as possible. I have tried all these methods and more. I have practiced them until I got the hang of it, and then timed the work. I snap all my lines, because that the quickest and easiest way to a good job.
P.S. Snapping lines can be really hard if you don't have the right chalkline (chalk box). You need a giant chalkline, not a carpenters chalkline. The very best chalkline for pavement contractors is the Magnum Chalkline from Parking Lot Planet.