Originally Posted by armyturtle
Is it unreasonable to assume I'm safe doing 75mph with my F150 raptor pulling my small 2900lb. jayco?
The state-wide 55MPH limit on interstates for Semis and vehicles pulling trailers is a California oddity, though a handful of other states have lower limits (60-70MPH) for trucks than passenger cars. Is the stated rationale specifically for safety? I assumed it was a hold over from the puritanical 55MPH fuel conservation era combined with California's poor air quality concerns?
Getting back to your question, you really cannot say you are safe in an absolute sense at any speed. It's all about the level of risk you're comfortable assuming for a given level of benefit. The faster you go, the higher the risk. Exceeding the design limit of components (tires, etc.) in your setup increases the risk at a faster rate. Moving faster increases both your frequency and severity of accidents, though moving closer to the average speed of traffic decreases the frequency of accidents somewhat (more benefit the greater the discrepancy).
Generally, a 65MPH limit is considered reasonably safe for Semis and trucks pulling trailers on at least some freeways in nearly the entire country.