The speed limit doesn't change - you simply find yourself in a position where you're forced to slow down for them.
Yes it is acceptable to momentarily accelerate over the speed limit tp get around a vehicle moving slower than the posted speed limit but you must return to the speed limit after passing.
In general the answer is, technically, no, you may not. However if you are passing a slower moving vehicle it would be considered 'lawful' to exceed the limit to pass the slower moving vehicle and then immediately return to the posted limit once it was passed.
Do not exceed the speed limit is correct
In practice, It is acceptable to increase the speed of your vehicle over the legal speed limit to pass or overtake another vehicle. Legally, it is not permitted. If the other vehicle is already at the speed limit, you should not be passing it. If it were a police car you were passing, at any speed above the speed limit, they could stop you.
Obviously you can, but if you get pulled over it's no excuse for speeding.ADDED: The speed limit is the speed LIMIT. Although some leeway may be granted to go around a slow moving vehicle, and then resume the lawful speed, it IS possible that you COULD be cited for exceeding the limit.
The speed limit is exactly that - the speed limit. While a reasonable excess of speed might be overlooked when overtaking another vehicle, there is no guarantee. You can be pulled over and cited for speeding, still.
The speed limit is applicable when overtaking another vehicle, just as it is at any other time. A police officer observing you overtaking another vehicle MIGHT decide what you did was within reason, and not bother you, but they have full authority to pull you over for exceeding the speed limit- even when overtaking a slower moving vehicle- should they decide to.
Fasten that safety belt before moving the vehicle; look both ways before pulling out from a stop; obey speed limit signs ... "speed limit" is not the speed you HAVE to go, rather the highest speed allowed for that road in that area.
In practice, It is acceptable to increase the speed of your vehicle over the legal speed limit to pass or overtake another vehicle. Legally, it is not permitted. If the other vehicle is already at the speed limit, you should not be passing it. If it were a police car you were passing, at any speed above the speed limit, they could stop you.
The same as it is for any other vehicle. Montana does not have a separate commercial vehicle speed limit, save for mountainous areas of downgrades where vehicle over 26,000 lbs. GVWR will have a lower speed limit indicated in signage.
The posted speed limit.
You fall when you jump from a moving vehicle because you get the moving vehicle speed and immediately you have your feet on a stable ground and you have either to stop all of sudden or to run at the vehicle speed (that is higher than your capacity) .