All the detail one could ask for. The "M" series documents deal with markings.
http://www.azdot.gov/business/engineering-and-construction/traffic/signing-and-marking-standard-drawings

1. 6"

2. 10' stripe 30' gap

Alan,

without you I would be lost. Thanks a lot!

This site has links to MUTCD Manuals that answer your question:         https://ceprofs.civil.tamu.edu/ghawkins/MUTCD-History.htm           They are general guidelines agreed to (but not always followed) by the Traffic Officials of the various States. There was much less uniformity between the State through the 1950's and even latter than there is today .        The 1948 MUTCD   CENTERLINES - white 4" to 6" wide, 15' line segments 25' gaps   NO PASSING ZONE  -  4" to 6" solid line(s)  yellow recommended, but white allowed   Yellow centerlines and no-passing lines did not become mandatory until 1970's                                                                                                                     

Check if the Department of Transportation for the relevant State(s) has posted their regulations online. Some do some historical data available. The federal guideline are contained in Title 23 Codeof Federal Regulations , but I would not recommend rummaging around in the CFR's unless are familiar with the regs or you enjoy frustration.

You may also find this site useful. I download and scale the signs for use on the layout. 

http://charm.cs.uiuc.edu/users/olawlor/projects/2003/roadsigns/

Michael T.

Michael T.: Thanks a lot, that is very helpful.

Michael

You might want to have a look at this tool  http://www.beugler.com/.  While designed for the automotive industry for pin striping it is used in a number of hobbies and crafts.  I bought one for my wife's craft several years ago but have since found it brilliant for doing road markings. It works great with standard acrylic paints such Delta Ceramcoat.  Easy to use free hand but they also come with a range of guides.

Cheers

Peter

Peter, thanks for the tip but I already have one . That's exactly what I was planning to use.