can someone tell where I can find free construction props and signs i found some on this site but the link did not work and some on other sites but rar. form and I could not open the file

Rar files are compression zip files and can be opened with Winrar.  You can download an evaluation from:

http://www.rarlab.com/

What types of things are you looking for? I've posted my framing nailer here a few weeks ago. I have several other objects such as ladders, saw-horses, piles of lumber, hand tools, etc...
I'd be happy to share whatever you need.

one guy posted hundreds of signs in freestuff here (linked to sharecg) but I dunno if they're still there.
they were rar archives.  in OS X, use unarchiver.app.

there are sign textures at www.cgtextures.com
you ned to use a prop square or other prop sign to apply them to .

bobcat loader with poser 7 or www.vanishingpoint.biz

Here are a few of the items I have.  extension ladder, step ladder, nailer, tool belt with pouch, hammer, bucket. Plenty more, if I can locate the discs they're stored on, including skill saw, chop saw, nails, various hand tools, cement mixer, shovels and rakes and implements of destruction (sorry, 'Alice's Restaurant' flashback).

I was looking for things like detour signs the links on this web site does not work