Hi please do feel free to check out this neat little script of mine on my tebex io page below.
https://tonimorton.tebex.io/package/4269823
Speedzones allow you to slow down (or stop) ai traffic in an area. (similar to a feature found in a common LSPDFR plugin as well as FivePD) well today im bringing that almost identical functionality to the masses for a very fair price. best part about it? well its standalone!. absolutely no dependencies!
This is a one time purchase of the script. future updates are 0.99$ (cents) USD per update (depending on demand for feature updates i may adjust pricing)
this script should work with any other scripts you have. it is command based currently however it can be setup to work with your custom UI or to have its own interface.
this script is currently only designed to work on a multiplayer fivem server. i dont have any idea how that translates to fivem singleplayer support
If you have any ideas or requests for future releases do contact me! 
Videos: