It is not mandatory in every state, I believe. However, even when not required, it is very common to use professional driving instructors with modified cars.
This is very uncommon in the United States. Probably 99% of driver training in the US is driving a family car with mom or dad in the passenger seat. Most people get very little and often no professional instruction.
Certainly, when receiving professional instruction, the modified car with at least an extra brake is typical. It's just that most people never get much of this instruction.
If you are under eighteen, states requiring driver's education from a professional driving school (with behind-the-wheel instruction): CA, DL, HI, ID, IA, KS, LA, MD, MA, MI, MN, MS, MT, NH, NJ, NM (waiver available), NY, NC, OH, PA, SC, TX, UT, VT, WA, WI,
Require the course, but not professional, behind-the-wheel instruction: CT, GA, FL, IL, KY, ME, MO, ND, RI, VA,
Professional instruction not required: AL, AK, AR, CO, IN, NE, NV, OK, OR, SD, TN, WV, WY, DC
So, about half of the country is required to have professional, in-car instruction. Quite common.
Still a huge number of people get no training and even in states that require training, it seems pretty minimal. 6 hours of driving instruction in my current state (WA) doesn't seem like a lot.
