Where is the 40 ft point on the trailer?

Where is the 40 ft point on the trailer? - TruckersReport

 

A semitrailer not more than 53 feet in length shall satisfy this requirement when configured with two or more rear axles, the rearmost of which is located 40 feet or less from the kingpin or when configured with a single axle which is located 38 feet or less from the kingpin...."
Quick Guide: Truck Lengths & Routes | Caltrans

 

If it's a 53 ft trailer with a 3 ft kingpin, 40' is 10' from the very back of the trailer.

 

If you had a $15 Rand McNally Motor Carrier Road Atlas it would have the answer to your question about CA and for every other state. No CDL driver should drive without it. It also lists the restricted routes for trucks in every state and low clearance locations in every state. At the end of the year you buy last year's version for sometimes as low at $10. They are the best purchase you can buy in trucking.

This is what they look like. I would not spend extra for the laminated page version.
https://www.amazon.com/Rand-McNally-Motor-Carriers-Atlas/dp/0528027204

 

40 foot mark is somewhere around the 5th or 6th hole I think. You need to grab a tape measurer to be sure

 

yup, 10', the swing door is 4', so twice as far as that.

 

Where to in Ca, from where?

 

The reason I was asking is, if you're coming in on i10, going to Bakersfield or North, just take AZ95 North at Quartzsite, > Parker, > vidal junction > i40 in needles. You can skip the banning scale. The small one in Mojave is closed after about 6pm at latest. Check truckerpath