State laws don't specifically make it illegal to engage in sexual acts while driving. However, doing so could result in a number of different charges.
The charges you might face for having sex while operating a vehicle depend on the circumstances and your state's laws.
To say the least, when a motorist engages in sexual acts while driving, there's a substantial risk he or she will be distracted from operating the vehicle safely. Most states have distracted driving laws that specifically prohibit activities like talking on a cellphone and text messaging while driving. But some states also have more general laws that make it illegal to do anything while operating a vehicle that distracts from driving safely. In states with these more general laws, sex while driving could certainly lead to a distracted driving ticket.
Distracted driving is normally a traffic infraction. Convicted motorists typically face fines and possibly demerit points on their driving record but no jail time.
Each state has its own specific definition of reckless driving. However, reckless driving laws generally make it illegal to operate a vehicle in a matter that shows a willful or reckless disregard for the safety of other people or property. Depending on the circumstances, having sex while driving could certainly qualify as reckless driving. Also, in one state, Washington, "embracing" another person while operating a vehicle is considered prima facie evidence of reckless driving.
Depending on the situation, having sex while driving could also lead to indecent exposure charges.
Indecent exposure is usually a misdemeanor. A conviction might carry fines and up to a year in jail. Some states also require sex offender registration for those convicted of indecent exposure.
If you've been cited for a violation, it might be worth hiring a traffic attorney. In most cases, a traffic attorney can go to court in your place and will know best how to handle your situation.