Adding new vehicle to fleet

What and where is the rule for WHEN you must UPDATE your DOT with any new vehicles? Is there a number of days that you legally have to update your DOT? or can someone please explain why I can't find a provision for this.

 

The Motor Carrier Safety Planner

Best answer i could find. Unless there is a more specific answer im unaware of. Better question. Its free and fairly easy to update online last i looked. So why wait?

 

Do not want to wait, but the interpretation by others in the organization appear to interpret that the only requirement in DOT is to update biennially; however, is there a provision in writing by DOT that supports this to be within x amount of days as it there should be but I cannot find it.

 

I wouldn't worry about it until your biennial update personally. The FMCSA doesn't enforce much of anything unless it's an easy cash grab IMO.